Academic Zigduino projects

A couple of interesting Zigduino projects in academic settings have recently been published. The first is from Frank Zhao, the author of the ZigduinoRadio package. He and his seminar group at the University of Waterloo created ARUCI: Augmented Reality Universal Controller and Identifier.

The second is a paper presented at IMECS 2013 about using Zigduinos andContiki to build loosely coupled wireless sensor networks. They are working with a middleware layer for building sensor networks called LooCI and evaluating how the Zigduino behaves with it.

New Zigduino r2 documentation and availability

First, the entire first spin of the Zigduino r2 sold out in two weeks. Since it's Chinese New Year, and our bare PCBs are made in China, it will be several weeks before we have more in stock. However, for those of you who do have them, we've got some amazing new documentation to show you. 

Arduino forum user pighixx has created gorgeous and detailed pinout diagrams for every official Arduino variant and a number of unofficial ones, including the Zigduino.

As you can see, it covers every pin and every function. I love these diagrams, and I am very glad pighixx was willing to create them for us! You can also download a PDF version.

Introducing the Zigduino r2

Along with the New Year comes a new version of the Zigduino! It's based on a number of comments and feature requests we've gotten from users. We've made the Zigduino significantly more useful for many of the applications they're talking to us about. We endeavoured to retain full backward compatibility for most applications. Here's the most significant changes:


  • FTDI FT231X USB to serial interface
  • D0/D1 connected to UART1; UART0 remains connected to the USB interface
  • All extra I/O brought out to a 2mm pitch auxiliary header
  • Arduino Uno R3 header pattern


  • Added LiPo battery connector
  • Added LiPo battery charging circuit
  • Added battery monitoring circuit
  • The USB interface powered by USB bus; unpowered when USB is not connected


  • Arduino Uno R3 board layout
  • Reset switch relocated to the side of the board, between the power jack and the power header


  • The external antenna replaced with an on-board antenna
  • Added a footprint for an MMCX connector, allowing installation of an external antenna for greater range.


  • Added footprint for clock crystal & loading capacitors

Taken together, these changes make the Zigduino a more capable platform for remote sensor nodes, remote controls, and similar applications. We look forward to seeing a host of new Zigduino applications that use these new features to their fullest.

All of the boards and connectors are now in hand -- right now, we're working on getting them all packed and programmed so we can offer them for sale by the end of January. In the meantime, we are now out of the r1 version and we do not anticipate making any more. There are still a few with our distributors, including SeeedStudio and Snootlabs.

New Products!

We have two exciting new products we'd like to tell you about. We introduced both of these for World MakerFaire New York

Current/Voltage Monitor

We've created a tiny current and voltage monitor for monitoring power flow. Despite its small size, it can measure currents up to 30A, both unipolar and bipolar. The broad traces, Hall effect current sensing element, and the ability to connect ring terminals as large as #10 minimizes the insertion loss from adding this monitor to your circuit. It's thin enough to fit inside a piece of 1/2 conduit, and still has two more mechanical tricks as well. The main contacts are 1-1/8" apart, which allows you (with standoffs) to bolt the monitor across the contacts of a standard 3/8 barrier terminal strip. There is also a cut line of holes on each side, allowing the board to be trimmed for easy installation into a standard breadboard.

Electrically, the board outputs two analog voltages. The first first, labeled Isense, is proportional to the current flowing across the board. The Vsense voltage is the voltage between the main conductor and the provided signal ground. The Vsense output is diode clamped to a value between signal ground and the 5V power rail for the current sensor.

We're currently stocking four different current ranges and two voltage ranges, all for $15/ea. If none of these meet your requirements, send us an email at and we'll be happy to assist you.

RGB LED Matrix Backpack

We're particularly proud of the second product we've just introduced, the RGB LED Matrix Backpack. It abstracts the multiplexing and driving operations required to drive one of our 60 mm 8x8 RGB LED Matrix displays and gives the user a simple-to-use I2C interface. An HT1632C does the heavy lifting of driving the matrix while an ATtiny2313 provides the I2C interface. Just transmit the desired pattern as a 24 byte string and the backpack displays it on the included LED matrix until you remove power or send a different pattern. 

We decided to duplicate our earlier blinkenlights demo (Part 1, Part 2) with the new backpack. We edge-taped four of them into an array, hooked up an Arduino, and displayed the same three games of life we did before. You can compare the size and complexity of the code for the original demo with that for the new demo we were showing of at World MakerFaire. We'll get a blog post up analyzing this demo in the next week or so.

The kit comes with everything in the picture above for $30.

What is ground?

The best electrical engineering advice I've ever gotten came in two parts one. First, when your circuit is behaving strangely, check the grounds. Second, only one point in your circuit is truly ground -- everything else is just close.

I just discovered, via Dangerous Prototypes, a great Maxim app note on the subject. For safety reasons, we generally want ground to be pretty close to our surroundings. But we still get to choose what it is and what its value is. Typically, the negative terminal of your power supply or battery is a good, safe place. But it's not the only choice, and freeing your mind acn lead you in some interesting directions.

Tutorial 4292: Where is Ground?

Revised Bridge Amplifier Released

After a short but frustrating delay, we're proud to announce the release of the second edition of our bridge amplifier board. It has a few changes we think will be interesting to our users. 

  • Upgraded excitation drive current to 40 mA
  • Changed output voltage to ±5V nominal
  • Solder pads for 0.138" pitch screw clamp connectors
  • Solder pads for bridge completion resistors
  • Added cut lines for trimming board to fit inside a Bulgin Ethernet Cable Joiner, for IP68 environmental and impact protection.



We're sponsoring the Open 7400 Logic contest again!

Dangerous Prototypes is running their Open 7400 Logic Competition for a second year. The goal of the contest is to make the coolest thing you can think of with standard 7400 series discrete logic chips. Last year's winners included a capacitance meter and a video card. I'm looking forward to what sort of awesome things this year's customers will build.

Once again, we are offering a pair of Zigduinos and a pair of 4x4 Driver shields as prizes for the competition

Der Blinken Lights (Part II -- Framebuffer)

Looking at the hardware from part I of this series, you may have realized that the addressing scheme of the individual pixels is likely to be a bit hinky, which is true. It's also necessary to rapidly scan through the columns in order to produce the illusion of a continuous image. The canonical way to do this is to store the image data in a frame buffer structured in such a way as to streamline writing the data out. Interface routines abstract the wiring and addressing shenanigans.