“Oh man, this would make a great picture. I wish there was someone else here to take our picture for us so we didn’t have to take a selfie!”

Has this ever happened to you?

Of course it has. You’re a human being in the 21st century who reads tech blogs.

The Nixie aims to solve that. It’s, as crazy as it feels to type this, a wearable selfie drone. A flying wristband, with a camera built in. When you’re ready for your close-up, it launches off your wrist, reorients to frame you in the shot, and then hovers back over for you to catch it.

The bad news? It’s… still pretty conceptual. It looks like they’ve got a prototype that can launch off your wrist and float away — but it’s still early days. They have a long way to go (this thing looks about as fragile as can be right now) — but even as a concept, it’s damned cool.

The good news? It’s a finalist in Intel’s Make It Wearable competition — meaning they’ve just scored themselves $50,000 and all of the mentorship, design help, and technical support a company like Intel can throw at them in order to make it real.

The project is the brainchild of Christoph Kohstall (a physics researcher at Stanford), and is built in collaboration with team members Jelena Jovanovic and Michael Niedermayr.



I can personally attest to the fact that lack of limbs is no impediment to mobility. In fact, snakes are masters of moving over all kinds of terrain where wheeled or legged robots usually fail. They’re also excellent swimmers, and they can even jump and glide. Part of what makes snakes so adaptable is how they can choose from a variety of gaits depending on what they’re trying to do or where they’re trying to go. Robot snakes can do this too, and in some ways, they can do it even better, because they can execute behaviors that real snakes don’t know how to do, like rolling longitudinally to climb up poles (or legs).

We don’t mean to say that robot snakes would have real snakes trounced. Far from it: we have a lot to learn about how, and why, snakes move the way they do. In the latest issue of Scienceresearchers from Georgia Tech, roboticists from Carnegie Mellon, and herpetologists from Zoo Atlanta describe how sidewinders climb up steep sandy slopes, and show how snake robots can learn from their technique.

http://www.youtube.com/watch?v=iJoxvIFGf4A Continue reading


Image: University of Pennsylvania MODLAB

Now flying robots that are also taking advantage of clever design to find the absolute minimum number of motors required for stable flight. And as you may have guessed from the headline, it’s not very many motors at all.

We’re used to seeing two types of hovering robots. The first type is the more traditional helicopter design, with a single main rotor (or two) and maybe a little tail rotor. The second type is the pervasive quadcopter (or hexacopter or octocopter or whatever). With a helicopter, you have to manage a very complex multiple-actuator likage system for control and stability, and quadcopters have at least as many motors as they do rotors.

The Modular Robotics Laboratory at the University of Pennsylvania has been seeing what it takes to reduce both the complexity and number of actuators of rotorcraft, and they’ve come up with some vey cool solutions. Let’s start with seeing what the minimum number of actuators that you need for controllable flight is:

http://www.youtube.com/watch?v=aEPf0QHVuMM Continue reading


Synthetic gene networks printed on paper and freeze-dried to produce inexpensive, sensitive field diagnostics. Diagonal stripe shows that different assays do not cross-react.

They’re not talking about electronics, though. They’re describing how they developed “paper-based synthetic gene networks” into a practical, and potentially revolutionary, diagnostic tool for detecting a wide range of biomolecular targets such as glucose and viruses.

It took them less than a day to produce a slip of paper that can detect the Ebola virus. Armed only with that slip and smartphone camera, a healthcare worker in the field could know within two hours—and sometimes in as little as 20 minutes—whether a patient is infected or not. And the doctor, nurse, or volunteer could do this without advanced skills, extensive sample preparation, expensive reagents, laboratory instruments, or even refrigeration. Continue reading


If you can print in 2D, can you print in 3D? Well, the technology is already here. You can print out 3-dimensional objects based on a working template, and they aren’t just for show. They actually work! Manufacturers can provide you with a template where you can print a broken part of a machinery, let’s say, a screw, rather than order then wait for a replacement to come in.

Alternatively, you can make a model replica of an expensive car, like a 1960 Aston Martin DB5 in a 1:3 scale then crash and burn it for entertainment, like how the makers of the James Bond flick, Skyfall did.

(Image Source: The Register).

3D printing is made possible by fusing layers upon layers of materials made from durable plastics and metals based on a template, designed with a 3D Computer Aided Design (CAD) software. Each layer is about 0.1 mm thick and consist of liquid, powder and sheet materials.

With this technology, and a 3D printer, you can create designs or print 3D models of just about anything under the sun, provided you have the templates. Just to give you a taste of what 3D printing can do, here are 20 amazing masterpieces made from 3D printing.

1. A Working Gun

In the past, 3D printed firearms easily break after firing a few rounds. However today, non-profit corporation Defense Distributed offers users to download the necessary files to print your own firearms provided you have a 3D printer at home.

Here’s a video of one of their creations firing at semi-auto and full-auto modes.

2. 3D Printed Acoustic Guitar

Scott Summi created the world’s first 3D printed acoustic guitar, which means the rest of us now know it can be done.

With 3D printing, guitars can be made with plastic, complete with the metal soundhole cover and heel joint. Apart from making working musical instruments, avid guitarists can also make a 3D replica of the guitars of their favorite musicians or idols.

3. Hand-Made Camera Lens

A camera lens is complex to create, but with 3D printing you can make your own lens and even stumble upon some creative and unique results.

The creator of this camera lens used acrylic to replace the glass on the lens and other tools and machines to combine the many small parts together. And best of all, the lens works! Check out these few pictures taken with 3D printed lens.

Continue reading



Soldering is one of the most fundamental skills needed to dabble in the world of electronics. The two go together like peas and carrots. And, although it is possible to learn about and build electronics without needing to pick up a soldering iron, you’ll soon discover that a whole new world is opened with this one simple skill. We believe that soldering should be a skill in everyone’s arsenal. In a world of increasing technological surroundings, we believe it is important that people everywhere be able to not only understand the technologies they use everyday but also be able to build, alter, and fix them as well. Soldering is one of many skills that will empower you to do just that.

In this tutorial we will go over the basics of through-hole soldering – also known as plated through-hole soldering (PTH), discuss the tools needed, go over techniques for proper soldering, and show you where you can go from there. We will also discuss rework as it pertains to through-hole soldering and give you some tips and tricks that will make fixing any piece of electronics a breeze. This guide will be for beginners and experts alike. Whether you’ve never touched an iron before or are looking for a little refresher, this tutorial has a little something for everyone.

let’s dive right in!

What is Solder?

Before learning how to solder, it’s always wise to learn a little bit about solder, its history, and the terminology that will be used while discussing it.

Solder, as a word, can be used in two different ways. Solder, the noun, refers to the alloy (a substance composed of two or more metals) that typically comes as a long, thin wire in spools or tubes. Solder, the verb, means to join together two pieces of metal in what is called a solder joint. So, we solder with solder!

Solder wire sold as a spool (left) and in a tube (right). These come in both leaded and lead-free varieties.

Leaded vs. Lead-free Solder – A Brief History

One of the most important things to be aware of when it comes to solder is that, traditionally, solder was composed of mostly lead (Pb), tin (Sn), and a few other trace metals. This solder is known as leaded solder. As it has come to be known, lead is harmful to humans and can lead to lead poisoning when exposed to large amounts. Unfortunately, lead is also a very useful metal, and it was chosen as the go-to metal for soldering because of its low melting point and ability to create great solder joints.

With the adverse effects of leaded soldering known, some key individuals and countries decided it was best to not use leaded solder anymore. In 2006, the European Union adopted the Restriction of Hazardous Substances Directive(RoHS). This directive, stated simply, restricts the use of leaded solder (amongst other materials) in electronics and electrical equipment. With that, the use of lead-free solder became the norm in electronics manufacturing.

Lead-free solder is very similar to its leaded counterpart, except, as the name states, it contains no lead. Instead is is made up of mostly tin and other trace metals, such as silver and copper. This solder is usually marked with the RoHS symbol to let potential buyers know it conforms to the standard.

Choosing the Right Solder for the Job

When it comes to manufacturing electronics, it’s best to use lead-free solder to ensure the safety of your products. However, when it comes to you and your electronics, the choice of solder is yours to make. Many people still prefer the use of leaded solder on account of its superb ability to act as a joining agent. Still, others prefer safety over functionality and opt for the lead-free.

Lead-free solder is not without its downfalls. As mentioned, lead was chosen because it performs the best in a situation such as soldering. When you take away the lead, you also take away some of the properties of solder that make it ideal for what it was intended – joining two pieces of metal. One such property is the melting point. Tin has a higher melting point than lead resulting in more heat needed to achieve flow. And, although tin gets the job done, it sometimes needs a little help. Many lead-free solder variants have what’s called a flux core. For now, just know that flux is a chemical agent that aids in the flowing of lead-free solder. While it is possible to use lead-free solder without flux, it makes it much easier to achieve the same effects as with leaded solder. Also, because of the added cost in making lead-free solder, it can sometimes be more expensive than leaded solder.

Aside from choosing leaded or lead-free solder, there are a number of other factors to consider when picking out solder. First, there are tons of other solder compositions out there aside from lead and tin. Check out the Wikipedia solder pagefor an extensive list of the different types. Second, solder comes in a variety of gauges, or widths. When working with small components, it’s often better to use a very thin piece of solder – the larger then number, the smaller the gauge. For large components, thicker wire is recommended. Last, solder comes in other forms besides wire. When getting into surface-mount soldering, you’ll see that solder paste is the form of choice. However, since this is a through-hole soldering tutorial, solder paste will not be discussed in detail.

Now that you know how to choose the best solder for the job, let’s move on to tools and more terminology.

Continue reading


Illustration: Manoharan Lab/Stanford University

What happens when you combine a buckyball with a diamondoid? As it turns out something wonderful for the prospects of molecular electronics. In fact, you get a new kind of material that conducts electricity in just one direction.

This conducting of electricity in one direction is the role of rectifiers, which take the form of diodes in computer chips. By shrinking these diodes down to the size of a nanoparticle it could shrink chip size while making devices faster and more powerful.

In research published in the journal Nature Communications, an international team of scientists Catholic University of Louvain in Belgium, Kiev Polytechnic Institute in Ukraine and Justus-Liebig University in Germany built on research conducted at the Department of Energy’s SLAC National Accelerator Laboratory back in 2007, which demonstrated that a single layer of diamondoids on a metal surface can efficiently emit a beam of electrons. Diamondoids are molecules found in petroleum that have the basic chemical structure of diamonds, but are coated on the outside in hydrogen molecules.

From that seven-year-old experiment, Hari Manoharan of the Stanford Institute for Materials and Energy Sciences (SIMES) at the Department of Energy’s SLAC National Accelerator Laboratory, and his team wondered what would happen if they combined the diamondoid with another particle that could grab the electrons. They knew that buckyballs, which are hollow carbon spheres, had that capability.

“We wanted to see what new, emergent properties might come out when you put these two ingredients together to create a ‘buckydiamondoid,’” said Manoharan in news release. “What we got was a basically a one-way valve for conducting electricity — clearly more than the sum of its parts.”

The researchers discovered that the buckyball and diamonoid hybrid, dubbed a ‘buckydiamonoid’, allowed electrical current to flow through it up to 50 times stronger in one direction, from electron-spitting diamondoid to electron-catching buckyball, than in the opposite direction.

Although this is not the first molecule-size rectifier ever developed, it does mark the first time one has been constructed solely from carbon and hydrogen. The researchers are going to see if they can make the transistors from the same two materials.

“Buckyballs are easy to make — they can be isolated from soot — and the type of diamondoid we used here, which consists of two tiny cages, can be purchased commercially,” said Manoharan. “And now that our colleagues in Germany have figured out how to bind them together, others can follow the recipe. So while our research was aimed at gaining fundamental insights about a novel hybrid molecule, it could lead to advances that help make molecular electronics a reality.”



These are Kilobots. They’re fairly simple little robots about the size of a quarter that can move around on vibrating legs, blink their lights, and communicate with each other. On an individual basis, this isn’t particularly impressive, but Kilobots aren’t designed to be used on an individual basis. Costing a mere $14 each and buildable in about five minutes, you don’t just get yourself one single Kilobot. Or ten. Or a hundred. They’re designed to swarm in the thousands, although the Harvard group that’s working on them is starting out with a modest 25:

We’ve seen lots of examples of swarm robotics, but what we decide to call a “swarm” often isn’t, really. There is (or should be, at any rate) a distinction between a group of robots cooperating on a task and a true swarm of robots, and for the purposes of this article, I’m going to arbitrarily assert that a group of robots turns into a swarm of robots when you can’t easily count how many individual robots there are. So like, swarming MAVs? Not really a swarm. Swarmanoid? Not a swarm yet. Swarm bots are getting closer. What definitely makes the cut are projects like RoboSwarm and FlyFire, which use anywhere from hundreds to thousands of small robots all at once. Continue reading


When Harvard roboticists first introduced their Kilobots in 2011, they’d only made 25 of them. When we next saw the robots in 2013, they’d made 100. Now the researchers have built one thousand of them. That’s a whole kilo of Kilobots, and probably the most robots that have ever been in the same place at the same time, ever

The researchers—Michael Rubenstein, Alejandro Cornejo, and Professor Radhika Nagpal of Harvard’s Self-Organizing Systems Research Group—describe their thousand-robot swarm in a paper published today in Science(they actually built 1024 robots, apparently following the computer science definition of “kilo”).

Despite their menacing name (KILL-O-BOTS!) and the robot swarm nightmares they may induce in some people, these little guys are harmless. Each Kilobot [pictured below] is a small, cheap-ish ($14) device that can move around by vibrating their legs and communicate with other robots with infrared transmitters and receivers.

A Kill-O-Bot

Two things are key to doing useful stuff with a swarm of robots like this. Thing one is having a lot of them, and one thousand most definitely qualifies as A LOT of them. In fact, researchers working on swarm robotics often rely on computer simulations (because digital robots are cheap!). When they built actual robots, their “swarm” consists of five robots or so. Maybe ten. Or a hundred, in rare cases.

But a thousand Kilobots—that’s a swarm. There are so many robots here that the importance of any individual robot is close to zero, which is a big part of the point of a swarm in the first place: robots can screw up, robots can break down, but there are so many of them that it just doesn’t matter, because their collective behavior prevails.

The second thing about swarm robotics is that you need the software and infrastructure to manage and control a huge number of robots. With a thousand robots, tasks that are trivial with a few robots rapidly scale to impossible. Charging is one example. Imagine if you had to manually plug 1000 robots to their chargers. For their Kilobots, the Harvard researchers solve this problem by sandwiching them between two metal sheets and passing a current through them. Similarly, you can rapidly program the robots by beaming infrared signals on them. And because you can do these operations (charging and programming) for all the robots at once, even if you increase the size of the swarm, the time required remains the same.

So once you’ve got your robots, and your charging, and your programming, what can you do? This:

http://www.youtube.com/watch?v=G1t4M2XnIhI Continue reading


A simple non-spammy trick to double the speed you upload to your Arduino board.

“Double your upload speed” sounds like a spammy internet site. There is however a really simple way to double the speed you upload to your Arduino.

Deselect Verify code after upload in the preferences window and click ok. That’s it. Don’t believe me? Open this big sketch that takes up ~30k of flash (nearly all the flash on a standard Uno). With the box checked it will take about 24 seconds to upload the file. With the box unchecked it will take about 13 seconds.

What’s going on here? By default the Arduino IDE verifies that everything was written correctly:

Program Step:

Arduino IDE: Hey
Uno: Oh hi
Arduino IDE: I've got some new code for you
Uno: Great! Send it to me
Arduino IDE: Here it is... [30k of bytes]
Uno: Got it, thanks!

Verify Step:

Arduino IDE: Hey
Uno: Oh hi
Arduino IDE: I'm not sure I trust you got everything correctly. Send your flash to me.
Uno: Ok, here it is... [30k of bytes]
Arduino IDE: [Compares Arduino bytes to original bytes] Hmm, looks ok. Please proceed.

This is how almost all programming routines work: send the code then verify if there were any errors during transmission. By skipping the verification step you reduce the number of bytes that have to be passed back and forth by half. What you may not realize is that there are at least two other error checks: one at the bootloader level (each frame of the STK500 bootloader has a cyclic redundancy check) and even lower at the USB to serial communication level (each USB frame has a CRC). If any communication gets corrupted it is caught and corrected at these levels. It is highly unlikely that your sketch will be recorded incorrectly to the Arduino when you hit  Upload.

Why does this matter?

Many sketches are a few thousand bytes so turning off verification will only save you a few seconds per upload. But how many times do you upload a sketch when you’re working on a project? 10 times? 50? It’s more than you might like to admit. And how many projects might you work on? I’ve probably uploaded tens of thousands of sketches over the past few years. Now multiply by all the Arduino users out there and you end up with a tremendous amount of wasted time.

Nathan: 25 sketch uploads * 100 days a year * 6 years = 15,000 uploads
Time wasted: Avg time savings of 5 seconds per upload * 15,000 uploads = 75,000s = 1250min = 20 hours
Arduino users (wild guess): 3,000,000 * 20 hours = 60,000,000 hrs = 2.5m days = 6,849 years of wasted time

These numbers are obviously unscientific but you get the idea. We’ll all be better off by spending less time watching the TX and RX LEDs blink.

Times when you might want verification

What a failed verification looks like in Arduino IDE

There are times when you may want to verify your code. If you’re going to deploy your Arduino into a satellite or into a final project you may sleep better knowing the code is correct. If you’ve got an extraordinary connection to an Arduino like a 50ft USB cable or a 2km connection over RS485 you may want to verify after upload. It’s still unlikely an error will slip through the CRCs so use your own judgement.

What boards does this trick work on?

This works with any Arduino that uses a serial to USB IC (Uno, Pro Mini, LilyPad Simple, Fio, etc). These boards all use the same avrdude bootloader that use the verification flag by default.

Any board using the Catarina booloader (Leonardo, Micro, etc) or the Halfkay bootloader  have much faster bootloaders that don’t see much, if any speed advantage.

 It’s perhaps better than 1 in a million but I’m not sure how to calculate the odds so please let me know if it has been. In 11 years of hammering on microcontrollers with serial bootloaders I’ve never seen an incorrect record to flash. Any firmware errors were always because of my own fault or faulty bootloader design.

Save time, trust your toolchain, and uncheck the box!

Source: Sparkfun



Internal diagram of the Darlington transistor array

These are great for doing a little heavy lifting with a microcontroller. Most micros can only source or sink about 20mA of current with each pin. If you’re trying to do something like drive a high-power multi-segment LED display, the current from a microcontroller pin just won’t cut it. You could run the micro outputs in parallel for more current, but then you lose pins for other purposes. Using an external array for the switching lets each pin drive a unique load at higher current, with the added benefit of offloading some of the heat from the microcontroller.

The ULN2003/4 and ULN2803/4 are 7- and 8-element Darlington arrays which can switch up to 500mA (MAX!) per channel at up to 50 volts. Channels can be combined to switch higher current loads (still 50V though). Take note of that “500mA MAX”: while the 2×03′scan switch that much current, they can’t do it forever, because they can’t dissipate the heat. The total amount of switchable current will depend on the number of channels you’re driving at the same time, and the duty cycle of the input signal. See the datasheet(PDF) for more information.

The 2xx3 chips have 2.7k input resistors, so they can be driven from a 5V TTL/CMOS line –if you’re using an Arduino, you should get the ULN2003/2803. The 2xx4 chips have 10.5k resistors for inputs of 6-15 volts.

These are great for driving multiple RGB lines with lots of LEDs, or a bank of relays or motors (they have clamp diodes built in!). The following illustrates how to properly connect the ULN for driving an inductive load like a DC motor.

Circuit shown to connect any load to the ULN2003 darlington array.



A 3D model of a shift register circuit with Arduino

Today I’ll attempt to teach you a little bit about Shift Registers. These are a fairly important part of Arduino programming, basically because they expand the number of outputs you can use, in exchange for only 3 control pins. You can also daisy-chain shift registers together in order to get even more outputs.

What Is A Shift Register?

An output shift register, technically speaking, receives data in serial and outputs it in parallel. In practical terms, this means we can quickly send a bunch of output commands to the chip, tell it to activate, and the outputs will be sent to the relevant pins. Instead of iterating through each pin, we simply send the output required to all the pins at once, as a single byte or more of information.

If it helps you to understand, you can think of a shift register as an ‘array’ of digital outputs, but we can skip the usual digitalWrite commands and simply send a series of bits to turn them on or off.

How Does It Work?

The shift register we will be using – the 74HC595N – needs only 3 control pins. The first is a clock – you needn’t worry too much about this as the Arduino serial libraries control it – but a clock is basically just an on/off electrical pulse that sets the pace for the data signal.

The latch pin is used to tell the shift register when it should turn its outputs on and off according to the bits we just sent it – i.e., latching them into place.

Finally, the data pin is where we sent the actual serial data with the bits to determine the on/off state of the shift register’s outputs.

The whole process can described in 4 steps:

  1. Set the data pin to high or low for the first output pin on the shift register.
  2. Pulse the clock to ‘shift’ the data into the register.
  3. Continue setting the data and pulsing the clock until you have set the required state for all output pins.
  4. Pulse the latch pin to activate the output sequence.


You need the following components for this project:

  • 7HC595N shift register chip
  • 8 LEDS and appropriate resistors, or whatever you want to output to
  • The usual breadboard, connectors, and a basic Arduino




The board layout:

shift register circuit from oomlout   Arduino Programming   Playing With Shift Registers (a.k.a Even More LEDs)

And my assembled version:

assembled shift register tutorial   Arduino Programming   Playing With Shift Registers (a.k.a Even More LEDs)


I’ve modified the original code provided by Ooolmout, but if you’d like to try that instead, it can be downloaded in full here. Explanation of the code is included, so copy and paste the whole thing from below to read an explanation of the code.

/*     ---------------------------------------------------------
 *     |  Shift Register Tutorial, based on                    | 
 *     |  Arduino Experimentation Kit CIRC-05                  |
 *     |          .: 8 More LEDs :. (74HC595 Shift Register)   |
 *     ---------------------------------------------------------
 *     |  Modified by James @ MakeUseOf.com                    |
 *     ---------------------------------------------------------

//Pin Definitions
// 7HC595N has three pins
int data = 2; // where we send the bits to control outputs 
int clock = 3; // keeps the data in sync
int latch = 4; // tells the shift register when to activate the output sequence

void setup()
   // set the three control pins to output
  pinMode(data, OUTPUT);
  pinMode(clock, OUTPUT);  
  pinMode(latch, OUTPUT);  
  Serial.begin(9600); // so we can send debug messages to serial monitor

void loop(){
    outputBytes(); // our basic output which writes 8-bits to show how a shift register works. 
    //outputIntegers(); // sends an integer value as data instead of bytes, effectively counting in binary. 
void outputIntegers(){
     for (int i=0;i<256;i++){
        digitalWrite(latch, LOW);     
        Serial.println(i);  // Debug, sending output to the serial monitor
        shiftOut(data, clock, MSBFIRST, i); 
        digitalWrite(latch, HIGH);   

void outputBytes(){
    /* Bytes, or 8-bits, are represented by a B followed by 8 0 or 1s. 
        In this instance, consider this to be like an array that we'll use to control
        the 8 LEDs. Here I've started the byte value as 00000001
    byte dataValues = B00000001; // change this to adjust the starting pattern
    /* In the for loop, we begin by pulling the latch low, 
        using the shiftOut Arduino function to talk to the shift register, 
        sending it our byte of dataValues representing the state of the LEDs
        then pull the latch high to lock those into place.
        Finally, we shift the bits one place to the left, meaning the next iteration
        will turn on the next LED in the series.
        To see the exact binary value being sent, check the serial monitor.
    for (int i=0;i<8;i++){
      digitalWrite(latch, LOW);     
      Serial.println(dataValues, BIN);  // Debug, sending output to the serial monitor
      shiftOut(data, clock, MSBFIRST, dataValues); 
      digitalWrite(latch, HIGH);   
      dataValues = dataValues << 1; // Shift the bits one place to the left -  change to >> to adjust direction

Bit-Shifting (OutputBytes Function)

In the first loop example – outputBytes() – the code utilises a 8-bit sequence (a byte) which it then shifts left each iteration of the for loop. It’s important to note that if you shift further than is possible, the bit is simply lost.

Bit-shifting is done using << or >> followed by the number of bits you want to shift by.

Check out the following example and make sure you understand what’s happening:

byte val = B00011010
val = val << 3 // B11010000
val = val << 2 // B01000000, we lost those other bits! 
val = val >> 5 // B00000010

Sending Integers Instead (OutputIntegers Function)

If you send a whole number to the shift register instead of a byte, it will simply convert the number into a binary byte sequence. In this function (uncomment in the loop and upload to see the effect), we have a for loop that counts from 0-255 (the highest integer we can represent with one byte), and sends that instead. It basically counts in binary, so the sequence may seem a little random unless your LEDs are laid out in a long line.

For example, if you read the binary explained article, you’ll know that the number 44 will be represented as 00101100, so LEDs 3,5,6 are going to light up at that point in the sequence.

binary 44   Arduino Programming   Playing With Shift Registers (a.k.a Even More LEDs)

Daisy Chaining More Than One Shift Register

The remarkable thing about Shift Registers is that if they are given more than 8-bits of information (or however large their registry is), they will shift the other additional bits out again. This means you can connect up a series of them together, push in one long chain of bits, and have it distributed to each register separately, all with no additional coding on your part.

Although we won’t be detailing the process or schematics here, if you have more than one shift register you can try the project from the official Arduino site here.



Amazing 3 dimensional LED display.

64 LEDs makes up this 4 by 4 by 4 cube, controlled by an Atmel Atmega328 microcontroller [I’m using an Arduino UNO]
Each LED can be addressed individually in software, enabling it to display amazing 3d animations!

Step 1:  You Will Need



First of all, you need quite a bit of time to solder together 64 leds ;)

Knowledge list:

    • Basic electronics and soldering skills
    • Know how to use an Arduino, programming an Arduino.

Component list:

  • An Arduino. The code supplied assumes an Arduino Uno, but could be adjusted to a larger model too.
  • 64 LEDs – the exact choice is up to you, but I used these superbright 3mm Blue LEDs
  • 16 Resistors of the appropriate value for your LEDs. Use ledcalc.com – enter 5v for the supply voltage, the voltage of the LEDs (in my case 3.2) and the current in milliamps (3.2). Your desired resistor will be shown in the box labelled “Nearest higher rated resistor”,
  • Some craft wire to strengthen basic structure and for decoration – I used 0.8mmthickness.
  • A prototyping board of some type that you can solder all your bits to. I used one which didn’t have full tracks along it as I don’t have a track cutter, but use whatever suits you. An Arduino prototyping shield is a little too small though, unless you really squeeze your LEDs together.
  • Random component wire – some network cable strands and some of the prototyping wires from a kit will work fine.
  • Crocodile clips or “helping hands” are useful for holding bits in place.
  • Soldering iron, and solder.
  • Some scrap wood.
  • A drill, with the same size bit as your LEDs.

Step 2 : The Principle Of This Design

Before you begin construction, it’s important to have an complete overview of how this thing is going to work so you can improvise and identify errors as you go along. Some LED cubes use a single output pin for every single LED – however in a 4x4x4 cube, that would need 64 pins – which we certainly don’t have on an Arduino Uno. One solution would be to use shift registers, but this is unnecessarily complicated.

In order to control all those LEDs in just 20 pins, we’ll be using a technique called multiplexing. By breaking the cube down into 4 separate layers, we only need control pins for 16 LEDs – so to light a specific LED, we must activate both the layer, and the control pin, giving us a total requirement of 16+4 pins. Each layer has a common cathode – the negative part of the circuit – so all the negative legs are joined together, and connected to a single pin for that layer.

On the anode (positive) side, each LED will be connected to the corresponding LED in the layer above and below it. Essentially, we have 16 columns of the positive legs, and 4 layers of the negative. Here’s some 3D views of the connections to help you understand:

Step 3 : Construction





Soldering grids of 4×4 LEDs freehand would look terrible!
To get 4 perfect 4×4 grids of LEDs, we use a template to hold the them in place.

Since we won’t be using a full metal structure to solder to, we want all the legs of the LEDs to overlap by about a quarter and give rigidity to the structure. Fold the cathode of your LEDs – the side with the flat notch in the head and the shorter leg – over as shown in the diagram. (It doesn’t really matter if you bend it left or right, so long as you’re consistent and it never touches the anode)

I wanted to make the cube as easy as possible to make, so I chose to use the LEDs own legs as much as possible. The distance between the lines in the grid was decided by the length of the LED legs. I found that 25mm (about an inch) was the optimal distance between each led (between the center of each led that is!) to enable soldering without adding or cutting wire.

Find a piece of wood large enough to make a 4×4 grid of 2,5cm on.

  • Draw up a 4×4 grid of lines.
  • Make dents in all the intersects with a center punch.
  • Find a drill bit that makes holes small enough so that the led will stay firmly in place, and big enough so that the led can easily be pulled out (without bending the wires..).
  • Drill the 16 holes.
  • Your ledcube template is done.

Step 4: Making the cube, solder the layers

Picture of Making the cube, solder the layers







We make the cube in 4 layers of 4×4 leds, then solder them together.

Create a layer:

  • Put in the LEDs along the back and along one side, and solder them together
  • Insert another row of LEDs and solder them together. Do one row at a time to leave place for the soldering iron!
  • Repeat the above step 2 more times.
  • add cross bracing in the front where the led rows are not connected.
  • Repeat 4 times.

Step 5: Making the cube, connecting the layers

Picture of Making the cube, connecting the layers



Now that we have those 4 layers, all we have to do is to solder them together.

Put one layer back in the template. This will be the top layer, so choose the prettiest one :)

Put another layer on top, and align one of the corners exactly 25mm (or whatever distance you used in your grid) above the first layer. This is the distance between the cathode wires.
Hold the corner in place with a helping hand and solder the corner anode of the first layer to the corner anode of the second layer. Do this for all the corners.

Check if the layers are perfectly aligned in all dimensions. If not bend a little to adjust. Or re-solder of it’s the height distance that’s off. When they are perfectly aligned, solder the remaining 12 anodes together.

Repeat 3 times.

Here is the circuit

For the four negative layers, I dropped a single wire down from each layer, then just pulled them off to the side

Step 6 : Programming Your Cube

Download the demo patterns and code from instructable user forte1994. He’s also provided a helpful online tool for designing the byte patterns to customize your own sequence.





Have you ever wondered what the black blob on the calculator or Remote or any other electronics PCB does, or at least is it any part or is it a misfired glue blob from the hot glue gun turned black!!!

This is a picture of a 16X2 LCD module with Chip On Board [COB]

Its actually called Chip On Board or [COB], and the black blob is the protective covering given to the bare bone chip which is the brain of any device that is in.

COB Manufacturing

Shown above is a tray of controller silicon dies that serve as the brain of the multimeter

The first step is to glue the silicon die to the PCB. I’m not entirely sure if the adhesive is conductive or not, but, judging by the exposed pad, it probably is.

With a pair of tweezers the dies are placed by hand(!). The adhesive sets within 5 minutes. This was another moment that caught me off guard: I assumed COB required a clean room with precision tools and ultra-accurate placement. It turns out, just like SMD soldering in a hot plate; you can have a lot of variance and still have a fully functional board.

The PCB is then inserted into an amazing automated wire bonding machine that bonds a very thin wire from the IC to the PCB. You can see the operator has to tell the visual recognition system a few alignment spots once in awhile, but in general, the machine quickly solders all the connections.

In this picture you can clearly see the Silicon chip connected to the pad by a mesh of wires.

Forty one connections later, and the die is all connected up. As you can see, the small theta rotation of the IC doesn’t make much of a difference.

A assembler squirting a small dab of potting compound over the entire structure.

The next step is to squirt a small dab of potting compound over the entire structure. This material electrically and physically protects the die and wire bonds from damage.

The viscosity of the compound must be tightly controlled to prevent the hairs from bending over and connecting with neighboring wires.

The liquid compound is then cured in an oven for four hours. Once complete the boards are tested and continue down the process of becoming a multimeter.



To connect a 12V relay to the Arduino you need the following things:

- 1 Arduino

- 1 diode for example 1N4007

- 1 NPN transistor for example 2N2222 (in the US) or BC548 (in Europe)

- 1 relay for example one with coil voltage 12V and switching voltage 125VAC/10 A

- 1 multimeter

Step 1: Measure the coil resistance

The Relay contacts

We are going to measure the coil resistance to calculate the current.

First we must find the coil:
On some relays the pins are labeled so you can just measure at pin 2 & 5.

Otherwise you have to measure at every pin:

Between two pins you should have between 100 and 10 000 Ohm. Remember that value. That are the two terminals of the coil. The coil is not polarized so its not important which one goes to V+ or GND.

If you have found those there are only three left. Between two should be a connection (if you measure a few Ohm its okay but everything above 50Ohm is too much). One of them is NC and one is COM. To find out which is which let one probe connected and connect the other to the pin that’s left over. If you connect the coil to 12V DC it should make a clicking noise. If your multimeter now shows a low resistance you have found COM and NO. The one probe you didn’t move is COM the other is NO

Step 2: Calculate how much current will flow

The formula you need is a simple one:

V = R * I

OK, but we want the current “I” right ? So just divide through the Resistance “R”.

V = R * I / :R

I = V/R

For my relay that would be:

I = 12V / 400Ohm
I = 0.03 A => 30 mA (That is Ic)

The Arduino can handle up to 20mA but its better to use a transistor even if your current is only 20mA. So for 30mA you definitely need one.

Step 3: Choose your transistor

First find the Datasheet of your transistor. For example search for “2N2222 datasheet”.

Your transistor should comply to  the following things:

- It has to be NPN not PNP !!

- Ic should be bigger than the value you calculated in step 2

- Vceo should be bigger than the supply voltage

Step 4: Calculating R1

You can find the value of hfe in your datasheet:
Mine says for BC548 its 75 at 10mA at 10V. Its not very precise cause its very difficult to build transistor with a accurate hfe.

hfe = Ic / Ib

We know hfe and Ic so lets calculate Ib:

Ib = Ic / hfe

For BC548:

Ib = 0.03 A / 75
Ib = 0.0004 A => 0.4 mA

Due to Ohms Law:

R1 = U / Ib
R1 = 5V / 0.0004 A
R1 = 12500 Ohm
This is not very accurate to so we use 10kOhm.

Step 5: Choosing your diode
The diode is needed cause the voltage will rise high if you suddenly change the voltage at the inductor. The formula for the voltage is:

V_L = – L * delta i/delta t

So theoretically if delta t equals zero U will be infinite.

But due to the minus in front you can add a diode in the “false direction” parallel to the relay. So the current can flow till its zero so the voltage is also zero.

Step 6: The schematic

Your datasheet says which pins are E, B and C.
Before you connect your Arduino connect a 4.5V Batteries negative terminal to GND and its positive terminal to R1. The relay should make a clicking noise if not, check your circuit.

Step 8: The Program


  • relaytest |
  • Author: Shriram |
  • Date: 12 May 2014 |
  • Function: Toggles Pin 13 every 10 Seconds |


int outPin = 13;

void setup()
pinMode(outPin, OUTPUT);

void loop()
digitalWrite(outPin, HIGH);
digitalWrite(outPin, LOW);

I know the program can be vastly edited and used, but all i needed was a program to check my relay, so this one did the job.
Until Next time
Source : Instructables


Source : IEEE

On 1 June 2009, Air France Flight 447, an Airbus A330-200, crashed into the Atlantic Ocean, killing all 216 passengers and 12 crew members. No one knows why the plane fell out of the sky, because no one has ever found its black box.

The plane plunged so deep that the black box’s sonar beacon could not be heard, and by the time the French navy had dispatched a submarine to the area, the beacon’s battery had evidently died. Crash analysts were thus reduced to poring over information the airliner had transmitted before going silent, information too sparse to determine what had happened, let alone how to prevent it from happening on some other airliner.

For half a century, every commercial airplane in the world has been equipped with one of these rugged, reinforced, waterproof boxes, which each house a flight data recorder and a cockpit voice recorder. For hundreds of crashes, they have given investigators the often heartbreaking details of the plane’s demise: the pilot’s frantic last words, his second-by-second struggles to keep the plane airborne, and the readings of the gauges and sensors that reveal such key parameters as the airspeed, altitude, and the state of the plane’s engines and flight-control surfaces. Such information has enabled analysts to infer the causes of most crashes and, often, to come up with preventive measures that have saved thousands of lives.

Every now and then, though, a black box is destroyed, lost beyond all chance of recovery or, as in the case of Air France 447, beyond all chance of detection. Lacking the black box and its precious data, we have no way to tell whether the last problem reported was the cause of the crash, the result of a deeper problem, or just an artifact of the sensor system on board. And because we can’t pinpoint the cause of the crash, we can take no steps to prevent similar failures in the future. Continue reading



 A real-time flight-data recording method could have given investigators a far better idea of what has happened to Malaysian Airlines Flight 370, says Krishna Kavi, a professor of computer science and engineering at the University of North Texas, in Denton.

Kavi, calling it the glass box, in contrast to the black box, which records flight data and voice data. The black box can be replayed only after the fact, and then only if it can be salvaged from an airliner’s wreckage; the proposed glass box would immediately transmit the data to the cloud—the network of servers that increasingly blankets the earth.

“I strongly believe that our version of the black box (glass box) would have provided information indicating that all components of the plane were operating” in the wayward MH 370,  he said in an email yesterday. “It would have provided data on speed, altitude, direction of the flight… in real time.”

In his article for Spectrum, Kavi wrote that “the airplane would transmit directly to the ground where possible, but when flying high or over water, it would have to resort to transmission via networks of satellites, some high up in geosynchronous orbit, others much lower down.” Satellite relays would be relatively slow, but still they could include all relevant flight data, at least in compressed form. Continue reading


Image: Boeing Artist’s concept of the Boeing Phantom Swift.

DARPA announced the four companies that’ll be competing to develop a new experimental aircraft that combines the efficiency of an airplane with the versatility of a helicopter. It’ll be something like a V-22 Osprey, except that DARPA is hoping for “radical improvements in vertical and cruise flight capabilities.” Three of the companies provided concept art to DARPA; Boeing’s Phantom Swift is pictured above. And the thing that every proposal has in common? They’re all robots. Continue reading


Tucked In: Protean’s in-wheel electric motors would be more powerful than others and save space under the hood.

An innovative in-wheel motor for electric vehicles may get its first tryout in the smoggy, traffic-choked streets of Beijing—and could lead to a wave of powerful and radically redesigned electric cars. Protean Electric, an automotive start-up headquartered in Auburn Hills, Mich., is currently scouting sites for a manufacturing center in China and says the assembly line will be operational before the end of the year. The company expects its first customers to be Chinese automakers, who will use the motor in their plug-in hybrids or pure electric cars.

Andrew Whitehead, Protean’s director of strategic alliances, says China is becoming a test bed for electric vehicle technology, thanks to strong government support. “The way we see it, the key driver for electric and hybrid technology at the moment are government standards on emissions,” says Whitehead. “The regulations in China are certainly as strict as in Europe and North America, but there appears to be more political will to assist the industry in reaching those standards in China than in the rest of the world.” Air pollution in China’s capital city has reached a crisis point, and both manufacturers and car buyers in China can now benefit from government incentives designed to replace polluting cars with cleaner electric vehicles.

While a typical EV has a central motor under the hood that sends power down the driveshaft to the axles, the Protean system generates power directly in small motors tucked inside the wheels. With no energy lost in transmission, Protean says its motors can provide significant efficiency gains. In addition, these gearless, direct-drive motors can each generate an impressive 1000 newton meters (738 foot-pounds) of torque each. By comparison, the all-electric Chevy Volt’s motor generates about 370 Nm (273 foot-pounds). Protean says that providing that much torque to individual wheels gives vehicles superior handling and performance. The power and control electronics, including the inverters that change DC battery power to AC power that drives the motor, are all tucked into the wheel space.


Continue reading


Flexible Electronics using Carbon Nano Tubes [CNT’s]

 There was a time, not so long ago, when carbon nanotubes (CNTs) were the “wonder material” that everyone was talking about—of course, that was before graphene hit the scene.

But even before graphene, researchers had begun to doubt whether CNTs were actually well suited for electronics applications. There are two stubborn obstacles that stand in the way of applying carbon nanotubes to electronics: it’s tricky to get them to go where you want them and it’s difficult to create CNTs that are homogeneous enough to ensure stable electrical responses. Continue reading



In this tutorial, you will learn all about the I2C communication protocol, why you would want to use it, and how it’s implemented.

The Inter-integrated Circuit (I2C) Protocol is a protocol intended to allow multiple “slave” digital integrated circuits (“chips”) to communicate with one or more “master” chips. Like the Serial Peripheral Interface (SPI), it is only intended for short distance communications within a single device. Like Asynchronous Serial Interfaces (such as RS-232 or UARTs), it only requires two signal wires to exchange information.

Why Use I2C?

To figure out why one might want to communicate over I2C, you must first compare it to the other available options to see how it differs.

What’s Wrong with Serial Ports?

Because serial ports are asynchronous (no clock data is transmitted), devices using them must agree ahead of time on a data rate. The two devices must also have clocks that are close to the same rate, and will remain so–excessive differences between clock rates on either end will cause garbled data. Continue reading


A battery awaits installation in a Telsa Motor Inc. Model S sedan at the company’s assembly plant in Fremont, California, U.S., on Wednesday, July 10, 2013.

Tesla Motors plans to build a huge U.S. battery factory capable of supplying 500 000 electric cars annually by 2020. The $5-billion “Gigafactory” is expected to produce more lithium ion batteries in 2020 than all the lithium-ion batteries produced worldwide in 2013—a huge step on the road to driving down the cost of battery packs and mass-market electric cars.

A completed Gigafactory running at full production capacity in 2020 would allow Tesla, founded by Silicon Valley entrepreneur Elon Musk, to have an annual battery cell output of 35 gigawatt-hours. The Gigafactory’s initial launch in 2017 would coincide with Tesla’s plans to introduce a lower-cost, mass-market electric car in the same year, according to The Wall Street Journal. But lower lithium-ion battery costs could also open the door for new power storage opportunities beyond electric cars. Continue reading


It’s Saturday afternoon and you have to drive your daughter to soccer practice and pick up her friend on the way. You also want to listen to a particular radio program and make some important phone calls. To make your driving experience easier, Mitsubishi Electric is developing predictive technology that will suggest a route based on your previous driving history, come up with an alternative route if you hit a traffic jam, and make it simple as pushing a button to find that radio program, make those phone calls, and even adjust the air conditioning to boot.

Mitsubishi expects to ship its Ultra-simple HMI (human-machine interface) technology for in-car operations to auto manufacturers from spring 2018. It demonstrated a prototype system in a recent Open House event at its headquarters in Tokyo.

In a mock-up driver’s seat, the driver was able to easily operate four main functions: navigation, phone, air conditioner, and audio-visual system. This was done in one or two steps using a set of three buttons on the steering wheel while viewing three predicted operations on a 44-cm heads-up display (HUD) on the windshield Continue reading


Touch ID is a fingerprint recognition feature, designed and released by Apple Inc., and currently only available on the seventh generation of iPhone, the iPhone 5S. Apple says Touch ID is heavily integrated into iOS 7 on supported devices, allowing users to unlock their phone, as well as make purchases in the various Apple digital media stores, all by quickly using one of up to five fingerprints the user can store on their device. Apple hopes for this to, at least partially, replace the user entering their passcode or password, although these are available as a backup method, and must also be used instead of Touch ID every once in a while. On announcing the feature, Apple made it clear that the fingerprint information is stored locally in a secure location on the Apple A7 chip on the device, rather than being cloud-based, making it very difficult for external access.

The Touch ID Sensor on iPhone 5s

Continue reading


To test the accuracy of a new fingerprint scanner, researchers typically run millions of known fingerprint images through the system’s matching software. But this testing procedure can’t quite mimic real operating conditions, as a 2-D image fed into a program is fundamentally different than a 3-D finger pressed to a sensor. Continue reading




In 2012, Clearpath Robotics decided to give away a customized Husky UGV to a worthy cause, and what could be more worthy than keeping us humans from getting blown up. The University of Coimbra in Portugal has taken its free Husky and turned it into an clever little autonomous mobile mine detector.

Huskies don’t come stock with the ability to detect mines. Or rather, they may be able to detect one single mine once. By accident. Catastrophically. To get the robot all set to not blow itself (or anyone else) into tiny little chunks, the team at Coimbra added sensors for navigation and localization (GPS, stereo vision, and a laser), as well as (more importantly) a customized two-degrees-of-freedom arm equipped with both a metal detector and a ground penetrating radar system. Continue reading



Injectable medical sensors and embedded implants are becoming less of a sci-fi trope as they manifest into reality. While most devices are either designed to be charged wirelessly or simply react with bodily fluids, cyborgs of the future may power such implants by sewing energy harvesters directly onto their internal organs.

A team of researchers from several U.S. academic institutions and one from China created a small, piezoelectric device that, when attached to a constantly moving organ — such as the heart, lung or diaphragm — can harness enough electricity to power a pacemaker or other medical implant.

The device incorporates lead zirconate titanate nanoribbons that are housed in a flexible, biocompatible plastic. Also included is an integrated rectifier that converts the electric signals, plus a miniature rechargeable battery. Constant motion of the organ causes the nanoribbons to bend, thus creating small amounts of electricity. Continue reading



Integrated circuits (ICs) are a keystone of modern electronics. They are the heart and brains of most circuits. They are the ubiquitous little black “chips” you find on just about every circuit board. Unless you’re some kind of crazy, analog electronics wizard, you’re likely to have at least one IC in every electronics project you build, so it’s important to understand them, inside and out.



Integrated circuits are the little black “chips”, found all over embedded electronics.

An IC is a collection of electronic components – resistors, transistors, capacitors, etc. – all stuffed into a tiny chip, and connected together to achieve a common goal. They come in all sorts of flavors: single-circuit logic gates, op amps, 555 timers, voltage regulators, motor controllers, microcontrollers, microprocessors, FPGAs…the list just goes on-and-on.

Covered in this Tutorial

  • The make-up of an IC
  • Common IC packages
  • Identifying ICs
  • Commonly used ICs

Inside the IC

When we think integrated circuits, little black chips are what come to mind. But what’s inside that black box?

51c0d009ce395feb33000000 Continue reading



Arduino is an open-source platform used for building electronics projects. Arduino consists of both a physical programmable circuit board (often referred to as a microcontroller) and a piece of software, or IDE (Integrated Development Environment) that runs on your computer, used to write and upload computer code to the physical board.

The Arduino platform has become quite popular with people just starting out with electronics, and for good reason. Unlike most previous programmable circuit boards, the Arduino does not need a separate piece of hardware (called a programmer) in order to load new code onto the board–you can simply use a USB cable. Additionally, the Arduino IDE uses a simplified version of C++, making it easier to learn to program. Finally, Arduino provides a standard form factor that breaks out the functions of the micro-controller into a more accessible package. For more info about the Arduino, check here and here.


This is an Arduino Uno

The Uno is one of the more popular boards in the Arduino family and a great choice for beginners. We’ll talk about what’s on it and what it can do later in the tutorial.

This is a screenshot of the Arduino IDE:


Believe it or not, those 10 lines of code are all you need to blink the on-board LED on your Arduino. The code might not make perfect sense right now, but our tutorials on getting started with Arduino will get you up to speed in no time!

In this tutorial, we’ll go over some of the things you can do with an Arduino, what’s on the typical Arduino board, and some of the different kinds of Arduino boards.

We will learn:

  • What you might use an Arduino for
  • What is on the typical Arduino board and why
  • The different varieties of Arduino boards
  • Some useful widgets to use with your Arduino

What does it do?

The Arduino hardware and software was designed for artists, designers, hobbyists, hackers, newbies, and anyone interested in creating interactive objects or environments. Arduino can interact with buttons, LEDs, motors, speakers, GPS units, cameras, the internet, and even your smart-phone or your TV! This flexibility combined with the fact that the Arduino software is free, the hardware boards are pretty cheap, and both the software and hardware are easy to learn has led to a large community of users who have contributed code and released instructions for a huge variety of Arduino-based projects.

The Arduino can be used as the brains behind almost any electronics project.

And that’s really just the tip of the iceberg – if you’re curious about where to find more examples of Arduino projects in action, here are some good resources for Arduino-based projects to get your creative juices flowing:

What’s on the board? Continue reading


Battery Options



There are a multitude of different battery technologies available. There are some really great resources available for the nitty gritty details behind battery chemistries. Wikipedia is especially good and all encompassing. This tutorial focuses on the most often used batteries for embedded systems and DIY electronics.


Here are some terms often used when talking about batteries.

Capacity – Batteries have different ratings for the amount of power a given battery can store. When a battery is fully charged, the capacity is the amount of power it contains. Batteries of the same type will often be rated by the amount of current they can output over time. For example, there are 1000mAh(milli-Amp Hour) and 2000mAh batteries.

Nominal Cell Voltage – The average voltage a cell outputs when charged. The nominal voltage of a battery depends on the chemical reaction behind it. A lead-acid car battery will output 12V. A lithium coin cell battery will output 3V.

The key word here is “nominal”, the actual measured voltage on a battery will decrease as it discharges. A fully charged LiPo battery will produce about 4.23V, while when discharged its voltage may be closer to 2.7V.

Shape – Batteries come in many sizes and shapes. The term ‘AA’ references a specific shape and style of a cell. There are a large variety.

Primary vs. Secondary – Primary batteries are synonymous with disposable. Once fully-drained, primary cells can’t be recharged (reliably/safely). Secondary batteries are better known asrechargeable. These require another power source to fully charge back up, but they can fully charge/discharge many times over their life. In general primary batteries have a lower discharge rate, so they’ll last longer, but they can be less economical than rechargeable batteries.

Common batteries, their chemistry, and their nominal voltage
Battery Shape Chemistry Nominal Voltage Rechargable?
AA, AAA, C, and D Alkaline or Zinc-carbon 1.5V No
9V Alkaline or Zinc-carbon 9V No
Coin cell Lithium 3V No
Silver Flat Pack Lithium Polymer (LiPo) 3.7V Yes
AA, AAA, C, D (Rechargeable) NiMH or NiCd 1.2V Yes
Car battery Six-cell lead-acid 12.6V Yes

Continue reading




Pull-up resistors are very common when using microcontrollers (MCUs) or any digital logic device. This tutorial will explain when and where to use pull-up resistors, then we will do a simple calculation to show why pull-ups are important.

What is a Pull-up Resistor

Let’s say you have an MCU with one pin configured as an input. If there is nothing connected to the pin and your program reads the state of the pin, will it be high (pulled to VCC) or low (pulled to ground)? It is difficult to tell. This phenomena is referred to as floating. To prevent this unknown state, a pull-up or pull-down resistor will insure that the pin is in either a high or low state, while also using a low amount of current.

For simplicity, we will focus on pull-ups since they are more common than pull-downs. They operate using the same concepts, except the pull-up resistor is connected to the high voltage (this is usually 3.3V or 5V and is often refereed to as VCC) and the pull-down resistor is connected to ground.

Pull-ups are often used with buttons and switches.

511568b6ce395f1b40000000 Continue reading



Have you ever needed a 12 volt power supply that can supply maximum 1 amp? But trying to buy one from the store is a little too expensive?

Well, you can make a 12 volt power supply very cheaply and easily!

Step 1: Things that you will need…


Things that you will need to make this power supply is…

  • Piece of protoboard
  • Four 1N4001 diodes
  • LM7812 regulator
  • Transformer that has an output of 14v – 35v AC with an output current between 100mA to 1A, depending how much power you will need.
  • 1000uF – 4700uF capacitor
  • 1uF capacitor
  • Two 100nF capacitors
  • Jumper wires (I used some plain wire as jumper wires)
  • Heatsink (optional)

Step 2: And the tools…

Also you will need the tools to make this power supply…

    • Soldering iron
    • Wire cutters
    • Wire strippers
    • A thing you can cut protoboard tracks.
    • Hot glue (To hold components down and make the power supply physically strong and sturdy.)
    • And some other tools that you might find helpful.

Okay, I think that is about it, lets get to work!

Step 3: Schematic and others…


Picture of Schematic and others...
If you want a 5 volt power supply, just simply replace the LM7812 to a LM7805 regulator.
Datasheet for LM78XX

If you are going to pull out about 1 amp from this power supply, you will need a heatsink for the regulator, otherwise it will generate very high temperatures and possibly burn out…
However, if you are just going to pull out a few hundred milliamps (lower than 500mA) from it, you won’t need a heatsink for the regulator, but it may get a little bit warm.

Also, here’s the schematic…
I also add in an LED to make sure the power supply is working. You can add in an LED if you want.

Step 4: Make it!


Make sure you get good solder joints and no solder bridges, otherwise your power supply won’t work!

Step 5: Test it!


After you had built your power supply, test it with your multimeter to make sure they are no solder bridges.

After you tested it, put it in a plastic box or something to protect you from shocks.
But do not operate the power supply like I did, it is very dangerous because of the mains voltage on the transformer, you or somebody will get badly shocked!

My power supply has 11.73v output, not too bad, I don’t need it to be exactly 12v…

Step 6: Done…



Source : Instructables



A loudspeaker playing a clip of President Barack Obama talking about 3-D printing in his State of the Union speech might not seem so remarkable—except that the loudspeaker represents one of the first 3-D printed consumer electronic devices in the world.

The 3-D printed loudspeaker is more expensive, took longer to make, and is of a lower quality than a typical mass-produced speaker, said Hod Lipson, an associate professor of mechanical and aerospace engineering at Cornell University. But he described his lab’s demonstration to IEEE Spectrum as providing a “glimpse of the future” by showing that 3-D printing technology can eventually create all the necessary components of electronic devices:

“The real challenge is one of material science: Can we make a series of inks that can serve as conductors, semiconductors, sensors, actuators, and power. These inks have to have good performance and be mutually compatible. We’re not there yet, but I think its well within reach—we’ll see a variety of platforms well within the next 5 years.”

Most 3-D printers usually build objects layer-by-layer from a single “passive” material such as plastic. But researchers have been testing how to use 3-D printing to squirt out conductive inks that can form the building blocks of integrated systems such as electronic devices.

The Cornell project—headed by mechanical engineering graduate students Apoorva Kiran and Robert MacCurdy—used two of the lab’s homegrown Fab@Home printers to create the 3-D printed loudspeaker parts. One printer made the plastic cone and base of the loudspeaker. The second printer laid down the wires on the cone and created a magnet inside the plastic base. (The team swapped out the second printer’s ink cartridge from conductor to magnet ink between printing runs.)

Silver ink provided the conductive material for the wire. For the magnet, Kiran enlisted the help of Samanvaya Srivastava, a graduate student in chemical and biomolecular engineering, to develop a strontium ferrite blend. Two Cornell undergraduates, Jeremy Blum and Elise Yang, also worked on the project.

The 3-D printed loudspeaker didn’t come out all in one piece—researchers manually moved the parts between the two printers and then snapped the cone and base together to complete the device. But Lipson says the complete loudspeaker could be printed on a single 3-D printer if the printer had multiple deposition tools capable of squirting out the different materials needed for the plastic, wires and magnet. Such printers could already be developed within labs in a month or so from a technical standpoint, but thebusiness demand is not there yet with 3-D printed electronics still in their infancy.

Lipson previously worked with former Cornell graduate students, Evan Malone and Matthew Alonso, to create a 3-D printed version of a working telegraph modeled on the Vail Register—the famous machine that Samuel Morse and Alfred Vail used to send the first Morse code telegraph in 1844. By comparison, the 3-D printed loudspeaker represents a relatively modern example of a commercial electronic device.

Once 3-D printing gets the hang of making electromagnetic systems, the technology could open the door for new customizable shapes and optimized performance for specific electronic devices—features that mass manufacturing can’t offer. Lipson described the idea of creating 3-D printed headsets, microphones, and other devices custom-made.

Eventually, 3-D printing could also revolutionize the manufacturing of robots. Lipson’s lab envisions using 3-D printers to build robots with “embedded wires and batteries shaped like limbs,” as well as all the other necessary components of robotic technology.

“We hope to be able to develop working electromagnetic motors in the future which would be the cornerstone upon which printed robots could be built,” said Robert MacCurdy, one of the Cornell graduate students heading the 3-D printed speaker project.


One day in 1994, seven world-leading technology companies sat down and created a new standard for connecting computer peripherals. By “one day,” of course I mean, “over the span of several months.” But all technicalities aside, the standard that they laid down became the Universal Serial Bus, or USB for short.

Today, USB is truly a ‘Universal’ standard and you’d be hard-pressed to find an electronic device that doesn’t have a USB port of one kind or another. But how do you know which USB cable will fit your device? Hopefully this buying guide will help you find the cable that you need for your next project.

What Does USB Do?

USB cables replace the huge variety of connectors that used to be standard for computer peripherals: Parallel ports, DB9 Serial, keyboard and mouse ports, joystick and midi ports… Really, it was getting out of hand. USB simplifies the process of installing and replacing hardware by making all communications adhere to a serial standard which takes place on a twisted pair data cable and identifies the device that’s connected. When you add the power and ground connections, you’re left with a simple 4-conductor cable that’s inexpensive to make and easy to stow.

500px-USB_half Continue reading


We had earlier in 2 different posts discussed about a variable power supply using LM 317. But in this post we discuss clearly about the working and designing of the LM 317 power supply in detailed.

Block Diagram

This circuit, like all voltage regulators  must  follow the same general block diagram


Here, we have got an input high voltage AC going into a transformer which usually steps down the high voltage AC from mains to low voltage AC required for our application. The following bridge rectifier and a smoothing capacitor to convert AC voltage into unregulated DC voltage. But this voltage will change according to varying load and input stability. This unregulated DC voltage is fed into a voltage regulator which will keep a constant output voltage and suppresses unregulated voltage ripples. Now this voltage can be fed into our load.

Firstly let us discuss about the need for the smoothing capacitance.As you know  the out put of the bridge rectifier will be as follows


As you can see, although the waveform can be considered to be a DC voltage since the output polarity does not invert itself, the large ripples Continue reading



In a masterful publicity stunt, Amazon CEO Jeff Bezos announced on 60 Minutes — on the night before Cyber Monday — that his company has been working on a drone service that will deliver items under 5 pounds, and within ten miles of an Amazon fulfillment center, in under 30 minutes..

This is definitely exciting, but exactly how much does Amazon have to accomplish between now and Jeff’s launch goal of 2015? Getting the FAA onboard will be hard enough, but what about actually getting shipments out safely, when that time finally comes? Is this even possible, or simply a publicity stunt by the e-commerce giant? They’re definitely not the first to think about doing this. Matternet has been working on bringing drone-supported shipping to areas of the world where roads aren’t common, or structurally sound enough, to handle everyday deliveries. CEO Andreas Raptopoulos talked about his vision at May’s Hardware Innovation Workshop.

If Amazon is really going for it, here are the main challenges and some of my thoughts on how Amazon will handle them:


Probably the easiest to deal with. Amazon says they’re shooting for 30 minute deliveries, which I’m assuming means 30 minutes from take-off to landing, not order to landing. Jeff says they will deliver to within 10 miles of an Amazon Fulfillment Center, which is doable if the octocopter can go at least 20mph. The challenge here is giving them enough battery power to survive the trip to the customer and back home. Carrying that much weight at that speed for up to an hour is going to require some heavy batteries. Continue reading


Build a motion-sensing alarm with a PIR sensor and an Arduino microcontroller.

In this simple project, we’ll build a motion-sensing alarm using a PIR (passive infrared) sensor and an Arduino microcontroller. This is a great way to learn the basics of using digital input (from the sensor) and output (in this case, to a noisy buzzer) on your Arduino.

This alarm is handy for booby traps and practical jokes, and it’s just what you’ll need to detect a zombie invasion! Plus, it’s all built on a breadboard, so no soldering required!

Step #1: Gather your parts.



  • This project requires just a few parts, and because you’re using a solderless breadboard and pre-cut jumper wires, you won’t need any tools at all — except your computer and USB cable to connect the Arduino.

Step #2: Wire the Arduino to the breadboard.

JHRErPeVwx4oQRk6 Continue reading



I bet some of you had the same problem. I was working on this circuit on breadboard and I found out I do not have means to power that circuit. Batteries are too expensive for testing one circuit. In the end I was able to build small power supply that solved my problems.

Many times we can build PSU with small amount of elements. That is the story in this case. I upgraded PSU that already have 12 V output to 9 V with help of linear voltage regulator.

Be careful and cautious while proceeding with any project.

Step 1: Parts and materials.



– low voltage connector
– 2 pins connector
– cooling element with nut and bolt and with isolating foil (foil is optional)
– piece of black and red wire and two pins
– 7809 voltage regulator
– 470 uF capacitor and 100 nF capacitor
– PSU with output between 12 and 16 V Continue reading


Whether it’s an electronic novice or an expert professional, a power supply unit is required by everybody in the field. It is the basic source of power that may be required for various electronic procedures, right from powering intricate electronic circuits to the robust electromechanical devices like motors, relays etc.
A power supply unit is a must for every electrical and electronic work bench and it’s available in a variety of shapes and sizes in the market and also in the form of schematics to us.
These may be built using discrete components like transistors, resistors etc. or incorporating a single chip for the active functions. No matter what the type may be, a power supply unit should incorporate the following features to become a universal and reliable with its nature:
  • It should be fully and continuously variable with its voltage and current outputs.
  • Variable current feature can be taken as an optional feature because it’s not an absolute requirement with a power supply, unless the usage is in the range of critical evaluations.
  • The voltage produced should be perfectly regulated.

IC 317 Power Supply, Simplest Continue reading



Every project needs a power supply. As 3.3volt logic replaces 5volt systems, we’re reaching for the LM317 adjustable voltage regulator , rather than the classic 7805 . We’ve found four different hobbyist-friendly packages for different situations.

A simple voltage divider  (R1,R2) sets the LM317 output between 1.25volts and 37volts; use this handy LM317 calculator  to find resistor values. The regulator does its best to maintain 1.25volts on the adjust pin (ADJ), and converts any excess voltage to heat. Not all packages are the same. Choose a part that can supply enough current for your project, but make sure the package has sufficient heat dissipation properties  to burn off the difference between the input and output voltages.

Voltage regulator

Schematic of LM317 in a typical voltage regulator configuration, including decoupling capacitors to address input noise and output transients.

The LM317 has three pins: Input, output, and adjustment. The device is conceptually an op amp (with a relatively high output current capacity). The inverting input of the amp is the adjustment pin, while the non-inverting input is set by an internal bandgap voltage referencewhich produces a stable reference voltage of 1.25V. Continue reading



think that it is safe to say that most of the people who make (big or small) electronics-projects have a pc or laptop in theire hobbycorner and a lot of projects need 5V for IC’s or microcontrollers. So using power from a USB cable isn’t that farfetched and lets face it: a lot of devices around us use a USB-connection to get their power or to charge their batteries.

 About USB-connectors and power

3 Continue reading


A well designed and variable power supply for electronics hobbyists and DIY’ers is a must, you don’t want to spend a huge amount of money in batteries [On the long run]. A variable power supply can come in handy for testing and powering  any project you are building. The mentioned power supply ranges from 1.25V – 37V @ 1.5A using the famous LM317 voltage regulator. LM317T is a very famous IC and easily available in the market comes with 3 pins, supporting input voltage is from 3 volt to 40 volt DC and delivers a stable output between 1.25 volt to 37 volt DC.


Whether you are watching it on television or searching for it on Pinterest, chances are you have admired a few Do It Yourself (DIY) projects recently. Have you taken it a step further and actually completed a DIY project? There are three key reasons why the trend of DIY projects is so popular.


The first reason that people want to try a DIY project is usually because it sounds like fun. You learn a new skill and the end result will be just what you are looking for. Since Halloween is just around the corner you may be thinking: “Should I go searching for the perfect costume or should I try to design and sew it myself?” Not everyone would have an interest and natural ability in making their own costume so learning to sew would seem like fun. Chances are you are artistic and enjoy ways to tangibly express that creativity. Now imagine taking it one step further and Continue reading



Touch screens are so ubiquitous that physical keyboards are becoming a thing of the past, at least for mobile devices. Now imagine if the capability of touch spread from the display to the entire device, allowing control by gently pressing on any part of the phone, or even making any household item into a touch-sensitive interface with your computer.

Anything solid vibrates a specific way when it’s hit physically with another object or with sound waves. The characteristic is called resonance. For example, when you tap on a crystal glass, it vibrates at a certain frequency, producing a ring. If you hit it with sound waves — for example, the ambient background noise in a room — it vibrates at a different frequency. Grip the glass while it rings, and the sound stops. Continue reading


As your embedded project grows in scope and complexity, power consumption becomes an ever more apparent issue. As power consumption increases, components like linear voltage regulators can heat up during normal operation. Some heat is okay, however when things get too hot, the performance of the linear regulator suffers.

How much is too much?

A good rule of thumb for voltage regulators is if the outer case becomes uncomfortable to the touch, then the part needs to have an efficient way to transfer the heat to another medium. A good way to do this is to add a heat sink as shown below.

breadboard Continue reading



This is a quick how-to explaining everything you need to get started using your Flexiforce Pressure Sensor.  This example uses the 25lb version, but the concepts learned apply to all the Flex sensors.



Necessary hardware to follow this guide:

  • Arduino UNO or other Arduino compatible board
  • Flexiforce Pressure Sensor
  • Breadboard
  • M/M Jumper Wires
  • 1 MegaOhm Resistor  Continue reading


Capacitors Galore

Capacitors are one of the most common elements found in electronics, and they come in a variety of shapes, sizes, and values. There are also many different methods to manufacture a capacitor. As a result, capacitors have a wide array of properties that make some capacitor types better for specific situations. I would like to take three of the most common capacitors – ceramic, electrolytic, and tantalum – and examine their abilities to handle reverse and over-voltage situations. Note: several capacitors were harmed in the making of this post.


Ceramic Capacitors

The most common capacitor is the multi-layer ceramic capacitor (MLCC). These are found on almost every piece of electronics, often in small, surface-mount variants. Ceramic capacitors are produced from alternating laye Continue reading


Power factor is a measure of how effectively you are using electricity. Various types of power are at work to provide us with electrical energy. Here is what each one is doing.

Working Power – the “true” or “real” power used in all electrical appliances to perform the work of heating, lighting, motion, etc. We express this as kW or kilowatts. Common types of resistive loads are electric heating and lighting.

An inductive load, like a motor, compressor or ballast, also requires Reactive Power to generate and sustain a magnetic field in order to operate. We call this non-working power kVAR’s, or kilovolt-amperes-reactive.

Every home and business has both resistive and inductive loads. The ratio between these two types of loads becomes important as you add more inductive equipment. Working power and reactive power make up Apparent Power, which is called kVA, kilovolt-amperes. We determine apparent power using the formula, kVA2 = kV*A.

Going one step further, Power Factor (PF) is the ratio of working power to apparent power, or the formula PF = kW / kVA. A high PF benefits both the customer and utility, while a low PF indicates poor utilization of electrical power.  Continue reading


Radio-Frequency Identification (RFID) is technology that allows machines to identify an object without touching it, even without a clear line of sight. Furthermore, this technology can be used to identify several objects simultaneously. RFID can be found everywhere these days – anything from your cat to your car contains RFID technology. This post will cover how RFID works, some practical uses, and maybe even some example code for reading RFID data.



What is RFID?

RFID is a sort of umbrella term used to describe technology that uses radio waves to communicate. Generally, the data stored is in the form of a serial number. Many RFID tags, contain a 32-bit hexadecimal number. At its heart, the RFID card contains an antenna attached to a microchip. When the chip is properly powered, it transmits the serial number through the antenna, which is then read and decoded. Continue reading