Elektor Publishes the Ultimate Intel Edison Manual

Elektor’s latest publication on the Intel Edison is a must have for all those with an active interest in the Internet of Things. The book, Getting Started with the Intel Edison, focuses its attention on the Edison, a tiny computer, the size of a postage stamp, with a  lot of power and built-in wireless communication capabilities. In 128 pages, renowned author Bert van Dam helps readers get up to speed with the Edison by making it accessible and easy to use.  It is not a projects book, but a toolbox and guide that allows you to explore the wonderful world of the Intel Edison.

Source: Elektor

Source: Elektor

This book shows readers how to install the software on the Edison as well as on a Windows PC. The Edison Arduino breakout board is used because it is easy to work with. Linux, Arduino C++ and Python are also used and plenty of examples given as to how the Edison can interface with other software. Covering Wi-Fi and Bluetooth, the book also shows you a trick to program sketches over Wi-Fi. Once you have completed the book, not only will your Edison be up and running with the latest software version, but you will also have sufficient knowledge of both hardware and software to start making your own applications. You will even be able to program the Intel Edison over USB and wirelessly both in Arduino C++ and Python. This book is educational and interesting, and really helps to build your knowledge of all things Intel Edison.

Getting started with the Intel Edison is currently available for $35.

Source: Elektor

Utilize Simple Radios with Simple Computers

I ordered some little UHF transmitters and receivers from suppliers on AliExpress, the Chinese equivalent of Amazon.com, in order to extend my door chimes into areas of my home where I could not hear them. These ridiculously inexpensive units are currently about $1 per transmitter-receiver pair in quantities of five, including shipping, and are available at 315 and 433.92 MHz. Photo 1 shows a transmitter and receiver pair.  Connections are power and ground and data in or out.

Photo 1: 315 MHz Transmitter-Receiver Pair (Receiver on Left)

Photo 1: The 315-MHz transmitter-receiver pair (receiver on left)

The original attempt at a door chime extender modulated the transmit RF with an audio tone and searched for the presence of that tone at the receiver with a narrow audio filter, envelope detector, and threshold detector. This sort of worked, but I started incorporating the same transmitters into another project that interfered, despite the audio filter.

The other project used Arduino Uno R3 computers and Virtual Wire to convey data reliably between transmitters and receivers. Do not expect a simple connection to a serial port to work well. As the other project evolved, I learned enough about the Atmel ATtiny85 processor, a smaller alternative to the Atmel ATmega328 processor in the Arduino Uno R3, to make new and better and very much simpler circuits. That project evolved to come full circle and now serves as a better doorbell extender. The transmitters self identify, so a second transmit unit now also notifies me when the postman opens the mailbox.

Note the requirement for Virtual Wire.  Do not expect a simple connection to a serial port to work very well.


Figure 1 shows the basic transmitter circuit, and Photo 2 shows the prototype transmitter. There is only the ATtiny85 CPU and a transmitter board. The ATtiny85 only has eight pins with two dedicated to power and one to the Reset input.

Figure 1: Simple Transmitter Schematic

Figure 1: Simple transmitter schematic

One digital output powers the transmitter and a second digital output provides data to the transmitter.  The remaining three pins are available to serve as inputs.  One serves to configure and control the unit as a mailbox alarm, and the other two set the identification message the transmitter sends to enable the receiver to discriminate among a group of such transmitters.

Photo 2: 315 MHz Transmitter and ATtiny85 CPU

Photo 2: The 315-MHz transmitter and ATtiny85 CPU

When input pin 3 is high at power-up, the unit enters mailbox alarm mode. In mailbox alarm mode, the input pins 2 and 7 serve as binary identification bits to define the value of the single numeric character that the transmitter sends, and the input pin 3 serves as the interrupt input. Whenever input pin 3 transitions from high-to-low or low-to-high, the ATtiny85 CPU wakes from SLEEP_MODE_PWR_DOWN, makes a single transmission, and goes back to sleep. The current mailbox sensor is a tilt switch mounted to the door of the mailbox. The next one will likely be a reed relay, so only a magnet will need to move.

When in SLEEP_MODE_PWR_DOWN, the whole circuit draws under 0.5 µA. I expect long life from the three AAA batteries if they can withstand heat, cold, and moisture. I can program the ATtiny to pull the identification inputs high, but each binary identification pin then draws about 100 µA when pulled low. In contrast, the 20- or 22-MΩ pull-up resistors I use as pull-ups each draw only a small fraction of a microampere when pulled low.

When input pin 3 is low at power-up, the unit enters doorbell extender alarm mode. In doorbell extender alarm mode, the input pins 2 and 7 again serve as binary identification bits to define the value of the single numeric character that the transmitter sends; but in doorbell extender mode, the unit repetitively transmits the identification character whenever power from the door chimes remains applied.


Figure 2 shows the basic receiver circuit, and Photo 3 shows the prototype receiver. There is only the ATtiny85 CPU with a 78L05 voltage regulator and a receiver board.

Figure 2: Simple Receiver Schematic

Figure 2: Simple receiver schematic

The receiver output feeds the input at pin 5. The Virtual Wire software decodes and presents the received character. Software in the CPU sends tone pulses to a loudspeaker that convey the value of the identification code received, so I can tell the difference between the door chime and the mailbox signals. Current software changes both the number of beep tones and their audible frequency to indicate the identity of the transmit source.

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Photo 3: The 315-MHz receiver with ATtiny85 CPU and 78L05 voltage regulator

Note that these receivers are annoyingly sensitive to power supply ripple, so receiver power must either come from a filtered and regulated supply or from batteries.

Photo 4 shows the complete receiver with the loudspeaker.

Photo 4: Receiver with antenna connections and loudspeaker

Photo 4: Receiver with antenna connections and a loudspeaker

Link Margin

A few inches of wire for an antenna will reach anywhere in my small basement. To improve transmission distance from the mailbox at the street to the receiver in my basement, I added a simple half-wave dipole antenna to both transmitter and receiver. Construction is with insulated magnet wire so I can twist the balanced transmission line portion as in Photo 5. I bring the transmission line out through an existing hole in my metal mailbox and staple the vertical dipole to the wooden mail post. My next mailbox will not be metal.

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

Photo 5: Simple half-wave dipole for both Tx and Rx increases link distance

I don’t have long term bad weather data to show this will continue to work through heavy ice and snow, but my mailman sees me respond promptly so far.

Operating Mode Differences

The mailbox unit must operate at minimum battery drain, and it does this very well. The doorbell extender operates continuously when the AC door chime applies power. In order to complete a full message no matter how short a time someone presses the doorbell push button, I rectify the AC and store charge in a relatively large electrolytic capacitor to enable sufficient transmission time.

Photo 6: New PCBs for receive and transmit

Photo 6: New PCBs for receive and transmit


This unit is fairly simple to fabricate and program your self, but if there is demand, my friend Lee Johnson will make and sell boards with pre-programmed ATtiny85 CPUs. (Lee Johnson, NØVI, will have information on his website if we develop this project into a product: www.citrus-electronics.com.) We will socket the CPU so you can replace it to change the program. The new transmitter and receiver printed circuit boards appear in Photo 6.

Dr. Sam Green (WØPCE) is a retired aerospace engineer living in Saint Louis, MO. He holds degrees in Electronic Engineering from Northwestern University and the University of Illinois at Urbana. Sam specialized in free space and fiber optical data communications and photonics. He became KN9KEQ and K9KEQ in 1957, while a high school freshman in Skokie, IL, where he was a Skokie Six Meter Indian. Sam held a Technician class license for 36 years before finally upgrading to Amateur Extra Class in 1993. He is a member of ARRL, a member of the Boeing Employees Amateur Radio Society (BEARS), a member of the Saint Louis QRP Society (SLQS), and breakfasts with the Saint Louis Area Microwave Society (SLAMS). Sam is a Registered Professional Engineer in Missouri and a life senior member of IEEE. Sam is listed as inventor on 18 patents.

Lighting and Motor Control Shields for Arduino

Arduino enthusiasts will be excited to learn that Infineon Technologies has announced two new shields for RGB lighting and motor control. You can use the shields—which are compatible to Arduino Uno R3—with the XMC1100 Boot Kit, which is equipped with a 32-bit microcontroller of the XMC1000 family (uses the ARM Cortex-M0 processor).


Infineon RGB XMC1202 for Arduino

The RGB LED Lighting Shield for Arduino features an XMC1202 microcontroller with its Brightness Color Control Unit (BCCU) for LED lighting control. The high-current DC Motor Control Shield for Arduino contains the Infineon NovalithIC BTN8982TA integrated half-bridge driver for motor control.

The RGB LED Lighting Shield evaluation board enables you to use different LED light engines for fast prototyping. It has three independent output channels for flicker-free control of multicolor LEDs. The BCCU automated hardware engine provides a cost-effective LED lighting solution dimming and color mixing. You can expand the shield with a DMX interface for lighting and audio nodes or a 24-GHz radar sensor for motion detection.

The DC Motor Control Shield with BTN8982TA simplifies the prototyping of DC motor control designs. It can drive two unidirectional DC motors or one bidirectional DC motor. The shield features two NovalithIC BTN8982TA fully integrated high-current half-bridge drivers optimized for motor drive applications. The BTN8982TA includes three ICs: two power chips (one p-channel high-side MOSFET and one n-channel low-side MOSFET) and an integrated driver IC with one logic circuit to control and monitor the power. Other features include are diagnosis with current sense and slew rate adjustment.

Until end of January 2015, both the RGB Lighting Shield with XMC1202 for Arduino and the DC Motor Control Shield with BTN8982TA for Arduino will be available for purchase from Newark element14. After that, they’ll also be available from Infineon and its distributors.

Source: Infineon

Robotics & Intelligent Gaming

When Alessandro Giacomel discovered Arduino in 2009, he quickly became hooked. Since then, he’s been designing “little robots” around Ardunio and blogging about his work and findings. In this interview, Alessandro tells us about his most interesting projects and shares his thoughts on the future of robotics, 3-D printing, and more.

CIRCUIT CELLAR: How long have you been designing embedded systems and what sparked your interest

ALESSANDRO: I have been designing embedded systems for about five years. My interest arose from the possibility of building robots. When I was a kid, I found robots extremely fascinating. The ability to force matter to do something we decided always seemed to be one of the main goals conceded to man.

CIRCUIT CELLAR: Tell us about your first design.

ALESSANDRO: My first embedded system was an Arduino 2009. The availability of a huge shield, sensors, and actuators has enabled me to design many applications at an acceptable price for an amateur like me.


Alessandro’s first robot

I started like many people, with a robot on wheels moving around avoiding obstacles. It’s a standard robot that almost all beginners build. It’s simple because it is built with only a few components and a standard Arduino 2009. The design included modified servomotors that can rotate 360° moving the robot and connected to the wheels and a servomotor to move a little head where there is an ultrasonic distance sensor. The distance sensor lets you know when the robot is in front of an obstacle and helps you decide the most convenient way for the robot to escape.

In its simplicity, this robot enables one to understand the basics for the development of a microcontroller-based robot: the need to have separate power supplies for the motors’ power circuits and for the microcontroller’s logic, the need to have precise sensor reading timing, and the importance of having efficient algorithms to ensure that the robot moves in the desired mode.

My first robot took me a long time to build. But all the elements of the robot (hardware and software) were developed by me and this was important because it let me begin to face the real problems that arise when you are building a robot. Today there are many resources on the Internet that enable one to build a robot simply replicating a set of steps anyone has described. These guides should be used as a source of inspiration, never followed exactly step-by-step, otherwise—while in the end it is true that you can build a robot—you don’t own the knowledge of what has been done.

My robot evolved with the ability to speak, thanks to a sound module. When I build a robot the goal is always to experiment with a technology and to have fun. My friends have enjoyed seeing the robot turning around, speaking, and telling funny stories.

CIRCUIT CELLAR: Your blog, Robottini (http://robottini.altervista.org), is described as “little robots with Arduino.” What inspired you to begin the blog

ALESSANDRO: I strongly believe in sharing knowledge and open-source hardware and software. I thought it was normal to try to share what I was designing when I started to build robots. When I started, I had the benefit of what others had made and published on the Internet. I thought about writing a blog in my language, Italian, but I thought also it would be a good exercise for me to try to write in English and, most importantly, this enabled me to reach a much wider audience.

The site description includes the philosophy at the basis of the blog: small robots built using Arduino. I build small robots because I’m an amateur and my house isn’t very big, so I only build robots that I can put in an armoire. I use Arduino because it is a microcontroller developed in Italy, it was obvious for me to use it, and it is really a great board for a beginner—inexpensive and robust.


Alessandro’s first robot at the Arduino Day 2011 event

The community has developed thousands of applications that can be reused. When I started the blog in 2011, I was building small robots for a few years. In the beginning, finding information was much more complicated and there were few shields that were not cheap. So, I always tried to use “poor” materials (e.g., recovered or recycled). Decreasing the cost of implementation and reusing and imagining new purposes for the things already available in a normal house seemed like a good way to work.

My achievements documented in the blog are never step-by-step guides to build the robot. I include a list of components to buy, the source code, and sometimes the wiring diagram. But I never provide a complete guide, since I think everyone should try to build their own robot because, once built, the satisfaction is enormous.

Through my blog I am available to help with problems people encounter when they are building robots, but I think it is important to give people the tools to build, rather than providing detailed explanations. Everyone can learn only by fighting the difficulties, without having someone preparing everything perfectly.

CIRCUIT CELLAR: Robottini obviously includes quite a few robotics projects. Why did you build them? Do you have a favorite?

ALESSANDRO: Many times people ask me what is the meaning of the robots I build. The answer that I give them leaves people puzzled. The answer is this: My robots are useless. They are useful only as fun—as a passion. I’m happy when I see my little son, Stefano, who is three years old, watching and laughing at a robot turning around in our house. But this does not mean I don’t follow a branch of research when I build robots.

Initially, I built robots to understand how the driver for the motors works, the sensors, and the problems related to the logic of the robot. Afterward, the first branch of research was the issue of control, how to set the proportional, integral, derivative (PID) control to follow a line or make a robot that is in balance. This has enabled me to address the management of complex sensors, such as the inertial measurement unit (IMU).

To have a robot balance on two wheels it is important to measure how much the robot is tilting from the vertical. To do this, typically a cluster of sensors is used, called IMU, which are based on multi-axes combinations of precision gyroscopes, accelerometers, magnetometers, and pressure sensors. In a more simple version, the IMU uses an accelerometer and a gyroscope, and it is mandatory to use both signals to obtain a correct value of the tilt angle from the vertical (it is called fusion of signals).

The most common method used is based on the Kalman filter, which is a mathematical tool that enables you to combine two or more signals to obtain the value of the angle. But it is a highly sophisticated and difficult for an amateur to understand, and it requires fairly advanced knowledge of mathematics. A new method that is rather simple has been proposed in the last years. It is called the “complementary filter.“

One of the studies I performed and posted on my blog compares in practice the signals of the two filters to verify if the complementary filter is able to approximate the Kalman filter in typical situations coming up in robotics. This post has had a great following, and I’ve been surprised to see that several university-level scientific publications have linked to it. I only wrote the post because I was curious to see a simple and almost trivial method that has become helpful to researchers and hobbyists. It has been a pleasure for me.

In the last year, I have followed the trend of art and interaction (i.e., the possibility of building something that can somehow marry art with technology). It was the theme of the stall I had at Maker Faire Europe in Rome, Italy, in October 2013. Arduino is an electronic circuit without a heart and without a soul. Can an Arduino be an artist? I’m trying to do something with Arduino that could be “art.” The arts include painting, poetry, music, sculpture, and so on. I’m trying to do something in different fields of art.

My first experiment is the Dadaist Poetry Box, which is a box capable of composing and printing Dadaist poems. It’s made with an Arduino and uses a printer for receipts to write poems. The box uses an algorithm to compose the poems in autonomy. You push the button and here is your Dadaist poem.


Dadaist poetry box design

Normally, the poem is a valuable asset, the result of an intimate moment when the poet transposes on paper the emotions of his soul. It is an inspired act, an act of concentration and transport. It’s not immediate. The poem box instead is trivial, it seems almost “anti-poem.” But it’s not; it’s a Dadaist poem. A user can push the button and have an original poem. I like the machine because it gives everyone something material to take home. In this way, the experience of interaction with the machine goes beyond the moment.

Another of my favorite robots is one that is capable of drawing portraits. I’ve never been good at drawing, and I’ve always been envious of those who can easily use a pencil to make a portrait. So I tried using my technical skills to fill this gap.


Portrait-drawing robot

The search of the algorithm that—starting from a picture—is able to detect the most important lines of the face has been particularly long and difficult. I used the OpenCV open-source libraries for computer vision and image processing, which are very powerful, but hard to handle. Installing the libraries is not a simple undertaking and using them is even more complicated. I used the OpenCV for Processing. Processing is an open-source programming language and integrated development environment (IDE) built for the electronic arts, new media art, and visual design communities with the purpose of teaching the fundamentals of computer programming in a visual context.

The algorithm initially found facial lines using the algorithms for calculation of edges of a picture. So I used the Canny edge detector, the Sobel edge detector, and all the other main edge detection algorithms, but none of these proved to be adequate to draw a face. Then I changed the course and used the Laplacian filter with threshold. I think I reached a good result because it takes less than 10 minutes to draw a portrait, which enables me to take pictures of people and make their portrait before they lose their patience.

CIRCUIT CELLAR: What new technologies excite you and why?

ALESSANDRO: I work almost strictly with Arduino microcontrollers. I was excited with the arrival of Linux-embedded mini-PCs (e.g., the Raspberry PI, the pcDuino, and BeagleBoard.org’s BeagleBone Black). Forcibly, I’m very intrigued by the new Arduino Tre, which is a mini-PC with Linux joined with an Arduino Leonardo. Combining a PC’s processing power of with Linux with the real-time management of the sensors and actuators made by an Arduino is an interesting road. It offers the possibility to manage the real-time processing of video streams through, for example, the OpenCV libraries, with the option of acquiring signals from analog sensors and the possibility of drive motors. For example, this enables one to have a completely autonomous 3-D printer and to perform the slicing and management of the 3-D printer. It also opens up new perspectives in the robotics and computer vision. The main limitation, which is now present in embedded systems, is the limited processing capacity. The ability to have in the same card a Linux system—with the world of applications and drivers already available—linked to the ability to manage physical devices brings a revolution. And I’m already excited to see the next results.

Read the complete interview in Circuit Cellar 292 November 2014.

Single-Board, Arduino Uno Shield-Compatible Dev Kit

Nordic Semiconductor’s new Arduino Uno shield-compatible nRF51 DK development kit supports Bluetooth Smart, ANT, and 2.4-GHz designs. Nordic also announced the availability of its nRF51 Dongle, which is a 16 mm × 28 mm USB dongle for the testing, analysis, and development of Bluetooth Smart, ANT, and 2.4-GHz applications.Nordic-nRF51 DK_1

The nRF51 DK is based on Nordic’s nRF51 Series SoC, which combines a 2.4-GHz multiprotocol radio, 32-bit ARM Corte M0 processor, flash memory, and 16- or 32-KB RAM. The SoCs can support a wide range of peripherals and are available in quad flat no-lead (QFN) and wafer level chip scale package (WLCSP) options.

Key points about the nRF51 DK and nRF51 Dongle

  • You can use the nRF51 DK with a variety of third-party Arduino shield expansion boards. It also supports ARM mbed for rapid prototyping projects.
  • The nRF51 DK allows access to all device peripherals, interfaces, and I/Os.
  • The nRF51 DK includes four user-programmable buttons and LEDS plus voltage and current pins to measure device power consumption.
  • nRF51 DK and nRF51 Dongle are supported by standard tool-chain options including Keil, IAR, and Gnu Compiler Collection (GCC).
  • The 63 mm × 101 mm nRF51 DK includes a coin-cell battery holder for field testing
  • You can use nRF51 DKhe DK as a programmer for other target boards that use the nRF51 Series SoC.

The nRF51 DK costs $69. The nRF51 Dongle is $49.

Source: Nordic Semiconductor

Arduino-Based Tube Stereo Preamp Project

If you happen to be electrical engineer as well as an audiophile, you’re in luck. With an Arduino, some typical components, and a little knowhow, you can build DIY tube stereo preamplifier design.

Shannon Parks—owner of Mahomet, IL-based Parks Audio—designed his “Budgie” preamp after reading an article about Arduino while he was thinking about refurbishing a classic Dynaco PAS-3.

Budgie preamp (Source: S. Parks)

Budgie preamp (Source: S. Parks)

In a recent audioXpress article about the project, Parks noted:

Over the last 10 years, I have built many tube power amplifiers but I had never built a tube preamplifier. The source switching seemed particularly daunting. A friend recommended that I refurbish a classic Dynaco PAS-3 which has been a popular choice with many upgrade kit suppliers. Unfortunately, the main part of these older designs is a clumsy rotary selector switch, not to mention the noisy potentiometers and slide switches. In the 1980s, commercial stereo preamplifiers started using IC microcontrollers that permitted cleaner designs with push-button control, relays for signal switching, and a wireless remote. While reading an article about the Arduino last year, I realized these modern features could easily be incorporated into a DIY preamplifier design.

All the circuits are on one custom PCB along with the power supply and microcontroller (Source: S. Parks)

All the circuits are on one custom PCB along with the power supply and microcontroller (Source: S. Parks)

Parks said the Arduino made sense for a few key reasons:

I found these features were incredibly useful:

  • A bank of relays could switch between the four stereo inputs as well as control mute, standby, gain, and bass boost settings.
  • A red power LED could use PWM to indicate if the preamplifier is muted or in standby.
  • An IR receiver with a remote could control a motor-driven volume potentiometer, change the source input selection, and turn the unit on/off. Any IR remote could be used with a code learning mode.
  • A backlit display could easily show all the settings at a glance.
  • Momentary push buttons could select the input device, bass boost, gain, and mute settings.
  • Instead of using several Arduino shields wired to an Arduino board, all the circuits could fit on one custom PCB along with the power supply and the microcontroller.

Parks used an Arduino Nano, which 0.73” × 1.70”. “The tiny Nano can be embedded using a 32-pin dual in-line package (DIP) socket, which cleans up the design. It can be programmed in-circuit and be removed and easily replaced,” he noted.

Parks used an Arduino Nano for the preamp project (Source: S. Parks)

Parks used an Arduino Nano for the preamp project (Source: S. Parks)

Parks described the shift register circuit:

The Budgie preamplifier uses a serial-in, parallel-out (SIPO) shift register to drive a bank of relays ….

A SIPO shift register is used to drive a bank of relays (Source: S. Parks)

A SIPO shift register is used to drive a bank of relays (Source: S. Parks)

Only four Arduino digital outputs—enable, clock, latch, and data—are needed to control eight DPDT relays. These correspond to the four outputs labeled D3, D4, D5, and D7 s …. The Texas Instruments TPIC6C595 shift register used in this project has heavy-duty field-effect transistor (FET) outputs that can handle voltages higher than logic levels. This is necessary for operating the 24-V relays. It also acts as a protective buffer between the Arduino and the relays.

Here you see the how to set up the Arduino Nano, LCD, power supply, push button , IR and motor control circuits (Source: S. Parks)

Here you see the how to set up the Arduino Nano, LCD, power supply, push button , IR and motor control circuits (Source: S. Parks)

As for the audio circuit, Parks explained:

The 12B4 triode was originally designed to be used in televisions as a vertical deflection amplifier. New-old-stock (NOS) 12B4s still exist. They can be purchased from most US tube resellers. However, a European equivalent doesn’t exist. The 12B4 works well in preamplifiers as a one-tube solution, having both high input impedance and low output impedance, without need for an output transformer. An audio circuit can then be distilled down to a simple circuit with few parts consisting of a volume potentiometer and a grounded cathode gain stage.
The 12B4 has about 23-dB gain, which is more than is needed. This extra gain is used as feedback to the grid, in what is often referred to as an anode follower circuit. The noise, distortion, and output impedance are reduced (see Figure 3). Using relays controlled by the Arduino enables switching between two feedback amounts for adjustable gain. For this preamplifier, I chose 0- and 6-dB overall gain. A second relay enables a bass boost with a series capacitor.
You only need a lightweight 15-to-20-V plate voltage to operate the 12B4s at 5 mA. Linearity is very good due to the small signal levels involved, as rarely will the output be greater than 2 VPP. A constant current source (CCS) active load is used with the 12B4s instead of a traditional plate resistor. This maximizes the possible output voltage swing before clipping. For example, a 12B4 biased at 5-mA plate current with a 20-kΩ plate resistor would drop 100 V and would then require a 120-V supply voltage or higher. Conversely, the CCS will only drop about 2 V. Its naturally high impedance also improves the tube’s gain and linearity while providing high levels of power supply noise rejection.

This article first appeared in Circuit Cellar’s sister publication, audioXpress (July 2014).



DIY Arduino-Based ECG System

Cornell University students Sean Hubber and Crystal Lu built an Arduino-based electrocardiography (ECG) system that enables them to view a heart’s waveform on a mini TV. The basic idea is straightforward: an Arduino Due converts a heartbeat waveform to an NTSC signal.

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s time base. (Source: Hubber & Lu)

Here you can see the system in action. The top line (green) has a 1-s time base. The bottom line (yellow) has a 5-s
time base. (Source: Hubber & Lu)

In their article, “Hands-On Electrocardiography,” Hubber and Lu write:

We used the Arduino Due to convert the heartbeat waveform to an NTSC signal that could be used by a mini-TV. The Arduino Due continuously sampled the input provided by the voltage limiter at 240 sps. Similar to MATLAB, the vectorized signal was shifted left to make room at the end for the most recent sample. This provided a continuous real-time display of the incoming signal. Each frame outputted to the mini-TV contains two waveforms. One has a 1-s screen width and the other has a 5-s screen width. This enables the user to see a standard version (5 s) and a more zoomed in version (1 s). Each frame also contains an integer representing the program’s elapsed time. This code was produced by Cornell University professor Bruce Land.

As you can see in the nearby block diagram, Hubber and Lu’s ECG system comprises a circuit, an Arduino board, a TV display, MATLAB programming language, and a voltage limiter.

The system's block diagram (Circuit Cellar 289, 2014)

The system’s block diagram (Circuit Cellar 289, 2014)

The system’s main circuit is “separated into several stages to ensure that retrieving the signal would be user-safe and that sufficient amplification could be made to produce a readable ECG signal,” Hubber and Lu noted.

The first stage is the conditioning stage, which ensures user safety through DC isolation by initially connecting the dry electrode signals directly to capacitors and resistors. The capacitors help with DC isolation and provide a DC offset correction while the resistors limit the current passing through. This input-conditioning stage is followed by amplification and filtering that yields an output with a high signal-to-noise ratio (SNR). After the circuit block, the signal is used by MATLAB and voltage limiter blocks. Directly after DC isolation, the signal is sent into a Texas Instruments INA116 differential amplifier and, with a 1-kΩ RG value, an initial gain of 51 is obtained. The INA116 has a low bias current, which permits the high-impedance signal source. The differential amplifier also utilizes a feedback loop, which prevents it from saturating.

Following the differentiation stage, the signal is passed through multiple filters and receives additional amplification. The first is a low-pass filter with an approximately 16-Hz cutoff frequency. This filter is primarily used to eliminate 60-Hz noise. The second filter is a high-pass filter with an approximately 0.5-Hz cutoff frequency. This filter is mostly used to eliminate DC offset. The total amplification at this stage is 10. Since the noise was significantly reduced and the SNR was large, this amplification produced a very strong and clear signal. With these stages done, the signal was then strong enough to be digitally analyzed. The signal could then travel to both the MATLAB and voltage limiter blocks.

Hubber and Lu’s article was published in Circuit Cellar 289, 2014. Get it now!

24-Channel Digital I/O Interface for Arduino & Compatibles

SCIDYNE Corp. recently expanded its product line by developing a digital I/O interface for Arduino hardware. The DIO24-ARD makes it easy to connect to solid-state I/O racks, switches, relays, LEDs, and many other commonly used peripheral devices. Target applications include industrial control systems, robotics, IoT, security, and education.Scidyne

The board provides 24 nonisolated I/O channels across three 8-bit ports. Each channel’s direction can be individually configured as either an Input or Output using standard SPI library functions. Outputs are capable of sinking 85 mA at 5 V. External devices attach by means of a 50 position ribbon-cable style header.

The DIO24-ARD features stack-through connectors with long-leads allowing systems to be built around multiple Arduino shields. It costs $38.

[Source: SCIDYNE Corp.]

Q&A with Arduino-Based Skube Codesigner

The Arduino-based Skube

The Arduino-based Skube

Andrew Spitz is a Copenhagen, Denmark-based sound designer, interaction designer, and programmer. Among his various innovative projects is the Arduino-based Skube music player, which is an innovative design that enables users to find and share music.

Spitz worked on the design with Andrew Nip, Ruben van der Vleuten, and Malthe Borch. Check out the video to see the Skube in action. On his blog SoundPlusDesign.com, Spitz writes: “It is a fully working prototype through the combination of using ArduinoMax/MSP and an XBee wireless network. We access the Last.fm API to populate the Skube with tracks and scrobble, and using their algorithms to find similar music when in Discover mode.”

Skube – A Last.fm & Spotify Radio from Andrew Nip on Vimeo.

The following is an abridged  version of an interview that appears in the December 2012 issue of audioXpress magazine, a sister publication of Circuit Cellar magazine..

SHANNON BECKER: Tell us a little about your background and where you live.

Andrew Spitz: I’m half French, half South African. I grew up in France, but my parents are South African so when I was 17, I moved to South Africa. Last year, I decided to go back to school, and I’m now based in Copenhagen, Denmark where I’m earning a master’s degree at the Copenhagen Institute of Interaction Design (CID).

SHANNON: How did you become interested in sound design? Tell us about some of your initial projects.

Andrew: From the age of 16, I was a skydiving cameraman and I was obsessed with filming. So when it was time to do my undergraduate work, I decided to study film. I went to film school thinking that I would be doing cinematography, but I’m color blind and it turned out to be a bigger problem than I had hoped. At the same time, we had a lecturer in sound design named Jahn Beukes who was incredibly inspiring, and I discovered a passion for sound that has stayed with me.

Shannon: What do your interaction design studies at CIID entail? What do you plan to do with the additional education?

Andrew: CIID is focused on a user-centered approach to design, which involves finding intuitive solutions for products, software, and services using mostly technology as our medium. What this means in reality is that we spend a lot of time playing, hacking, prototyping, and basically building interactive things and experiences of some sort.

I’ve really committed to the shift from sound design to interaction design and it’s now my main focus. That said, I feel like I look at design from the lens of a sound designer as this is my background and what has formed me. Many designers around me are very visual, and I feel like my background gives me not only a different approach to the work but also enables me to see opportunities using sound as the catalyst for interactive experiences. Lots of my recent projects have been set in the intersection among technology, sound, and people.

SHANNON: You have worked as a sound effects recordist and editor, location recordist and sound designer for commercials, feature films, and documentaries. Tell us about some of these experiences?

ANDREW: I love all aspects of sound for different reasons. Because I do a lot of things and don’t focus on one, I end up having more of a general set of skills than going deep with one—this fits my personality very well. By doing different jobs within sound, I was able to have lots of different experiences, which I loved! nLocation recording enabled me to see really interesting things—from blowing up armored vehicles with rocket-propelled grenades (RPGs) to interviewing famous artists and presidents. And, documentaries enabled me to travel to amazing places such as Rwanda, Liberia, Mexico, and Nigeria. As a sound effects recordist on Jock of the Bushvelt, a 3-D animation, I recorded animals such as lions, baboons, and leopards in the South African bush. With Bakgat 2, I spent my time recording and editing rugby sounds to create a sound effects library. This time in my life has been a huge highlight, but I couldn’t see myself doing this forever. I love technology and design, which is why I made the move...

SHANNON: Where did the idea for Skube originate?

Andrew: Skube came out of the Tangible User Interface (TUI) class at CIID where we were tasked to rethink audio in the home context. So understanding how and where people share music was the jumping-off point for creating Skube.

We realized that as we move more toward a digital and online music listening experience, current portable music players are not adapted for this environment. Sharing mSkube Videousic in communal spaces is neither convenient nor easy, especially when we all have such different taste in music.

The result of our exploration was Skube. It is a music player that enables you to discover and share music and facilitates the decision process of picking tracks when in a communal setting.

audioXpress is an Elektor International Media publication.

Arduino USB Host Shield

The Arduino USB Host Shield allows you to connect a USB device to your Arduino board. The Arduino USB Host Shield is based on the MAX3421E, which is a USB peripheral/host controller containing the digital logic and analog circuitry necessary to implement a full-speed USB peripheral or a full-/low-speed host compliant to USB specification rev 2.0.ArduinoHostshield

The shield is TinkerKit compatible, which means you can quickly create projects by plugging TinkerKit modules onto the board. The following device classes are supported by the shield:

  • HID devices: keyboards, mice, joysticks, etc.
  • Game controllers: Sony PS3, Nintendo Wii, Xbox360
  • USB to serial converters: FTDI, PL-2303, ACM, as well as certain cell phones and GPS receivers
  • ADK-capable Android phones and tables
  • Digital cameras: Canon EOS, Powershot, Nikon DSLRs and P&S, as well as generic PTP
  • Mass storage devices: USB sticks, memory card readers, external hard drives, etc.
  • Bluetooth dongles

For information on using the shield with the Android OS, refer to Google’s ADK documentation. Arduino communicates with the MAX3421E using the SPI bus (through the ICSP header). This is on digital pins 10, 11, 12, and 13 on the Uno and pins 10, 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the MAX3421E.

[Source: Arduino website via Elektor]

Nesit (Meriden, CT, USA)

NESIT wants to create, educate, and foster learning in the fields of various technological and other disciplines. They reap the benefits of productivity through volunteer collaboration.

Location 290 Pratt St., Meriden CT 06450
Members 30
Website nesit.org

Read about what Vice President Will Genovese has to say about NESIT.
Tell us about your meeting space!

NESIT meets in a 4000 square feet office that takes place in The Meriden Enterprise Center. A large office and manufacturing building that is home to over 60 businesses.

What tools do you have in your space? 

Soldering stations, oscilloscope, 3-D printer, woodshop, cnc, and a data center.

Are there any tools your group really wants or needs?

A lasercutter would be a nice addition to our arsenal.

What sort of embedded tech does your Hackerspace work with?

We work with PIC, Arduino, and Raspberry Pi, and many more.
In fact one of our recent projects was a DIY PIC Programmer.

Can you tell us about some of your group’s recent tech projects?


One of the group’s first tech projects was the “MAME,” a full-size gaming arcade. The project was going well until there was a break in at the location and they lost some equipment; the MAME was put on the backburner.  After they moved to their new location and gained a new member, an art teacher named John, the project garnered interest again. He came up with the design for it. Afterwords it was painted, they got a coin mechanism, speakers were hooked up, and the software was installed and configured. IT was finally finished.

Click here if you want to check it out.

What’s the craziest project you’ve completed?

At the moment we have not yet completed projects I would categorize as “crazy.”

Read more about NESIT on their website. 

Show us your hackerspace! Tell us about your group! Where does your group design, hack, create, program, debug, and innovate? Do you work in a 20′ × 20′ space in an old warehouse? Do you share a small space in a university lab? Do you meet at a local coffee shop or bar? What sort of electronics projects do you work on? Submit your hackerspace and we might feature you on our website!

Engineering Consultant and Roboticist

Eric Forkosh starting building his first robot when he was a teenager and has been designing ever since. This NYC-based electrical engineer’s projects include everything from dancing robots to remote monitoring devices to cellular module boards to analog signals—Nan Price, Associate Editor

NAN: Tell us about your start-up company, Narobo.


Eric Forkosh

ERIC: Narobo is essentially the company through which I do all my consulting work. I’ve built everything from dancing robots to cellular field equipment. Most recently I’ve been working with some farmers in the Midwest on remote monitoring. We monitor a lot of different things remotely, and I’ve helped develop an online portal and an app. The most interesting feature of our system is that we have a custom tablet rig that can interface directly to the electronics over just the USB connection. We use Google’s Android software development kit to pull that off.

ERIC: The DroneCell was my second official product released, the first being the Roboduino. The Roboduino was relatively simple; it was just a modified Arduino that made building robots easy. We used to sell it online at CuriousInventor.com for a little while, and there was always a trickle of sales, but it was never a huge success. I still get a kick out of seeing Roboduino in projects online, it’s always nice to see people appreciating my work.


The DroneCell is a cellular module board that communicates with devices with TTL UARTs.

The DroneCell is the other product of mine, and my personal favorite. It’s a cellular module board geared toward the hobbyist. A few years ago, if you wanted to add cellular functionality to your system you had to do a custom PCB for it. You had to deal with really low voltage levels, very high peak power draws, and hard-to-read pins. DroneCell solved the problem and made it very easy to interface to hobbyist systems such as the Arduino. Putting on proper power regulation was easy, but my biggest design challenge was how to handle the very low voltage levels. In the end, I put together a very clever voltage shifter that worked with 3V3 and 5 V, with some calculated diodes and resistors.

NAN: Tell us about your first project. Where were you at the time and what did you learn from the experience?


Eric’s Butler robot was his first electronics project. He started building it when he was still in high school.

ERIC: The Butler robot was my first real electronics project. I started building it in ninth grade, and for a really stupid reason. I just wanted to build a personal robot, like on TV. My first version of the Butler robot was cobbled together using an old laptop, a USB-to-I/O converter called Phidgets, and old wheelchair motors I bought on eBay.

I didn’t use anything fancy for this robot, all the software was written in Visual Basic and ran on Windows XP. For motor controllers, I used some old DPDT automotive relays I had lying around. They did the job but obviously I wasn’t able to PWM them for speed control.

My second version came about two years later, and was built with the intention of winning the Instructables Robot contest. I didn’t win first place, but my tutorial “How to Build a Butler Robot” placed in the top 10 and was mentioned in The Instructables Book in print. This version was a cleaner version of everything I had done before. I built a sleek black robot body (at least it was sleek back then!) and fabricated an upside-down bowl-shaped head that housed the webcam. The electronics were basically the same. The main new features were a basic robot arm that poured you a drink (two servos and a large DC motor) and a built-in mini fridge. I also got voice command to work really well by hooking up my Visual Basic software with Dragon’s speech-to-text converter.

The Butler robot was a great project and I learned a lot about electronics and software from doing it. If I were to build a Butler robot right now, I’d do it completely differently. But I think it was an important to my engineering career and it taught me that anything is possible with some hacking and hard work.

At the same time as I was doing my Butler robot (probably around 2008), I lucked out and was hired by an entertainer in Hong Kong. He saw my Butler robot online and hired me to build him a dancing robot that was synced to music. We solved the issue of syncing to music by putting dual-tone multi-frequency (DTMF) tones on the left channel audio and music on the right channel. The right channel went to speakers and the left channel went to a decoder that translated DTMF tone sequences to robot movement. This was good because all the data and dance moves were part of the same audio file. All we had to do was prepare special audio files and the robot would work with any music player (e.g., iPod, laptop, CD, etc.). The robot is used in shows to this day, and my performer client even hired a professional cartoon voice actor to give the robot a personality.

NAN: You were an adjunct professor at the Cooper Union for the Advancement of Science and Art in New York City. What types of courses did you teach and what did you enjoy most about teaching?

ERIC: I will be entering my senior year at Cooper Union in the Fall 2014. Two years ago, I took a year off from school to pursue my work. This past year I completed my junior year. I taught a semester of “Microcontroller Projects” at Cooper Union during my year off from being a student. We built a lot of really great projects using Arduino. One final project that really impressed me was a small robot car that parallel parked itself. Another project was a family of spider robots that were remotely controlled and could shrink up into a ball.

Cooper Union is filled with really bright students and teaching exposed me to the different thought processes people have when trying to build a solution. I think teaching helped me grow as a person and helped me understand that in engineering—and possibly in life—there is no one right answer. There are different paths to the same destination. I really enjoyed teaching because it made me evaluate my understanding about electronics, software, and robotics. It forced me to make sure I really understood what was going on in intricate detail.

NAN: You have competed in robotics competitions including RoboCup in Austria. Tell us about these experiences—what types of robots did you build for the competitions?


Eric worked with his high school’s robotics team to design this robot for a RoboCup competition.

ERIC: In high school I was the robotics team captain and we built a line-following robot and a soccer robot to compete in RoboCup Junior in the US. We won first place in the RoboCup Junior Northeast Regional and were invited to compete in Austria for the International RoboCup Junior games. So we traveled as a team to Austria to compete and we got to see a lot of interesting projects and many other soccer teams compete. I remember the Iranian RoboCup Junior team had a crazy robot that competed against us; it was built out of steel and looked like a miniature tank.

My best memory from Austria was when our robot broke and I had to fix it. Our robot was omnidirectional with four omni wheels in each corner that let it drive at any angle or orientation it wanted. It could zigzag across the field without a problem. At our first match, I put the robot down on the little soccer field to compete… and it wouldn’t move. During transportation, one of the motors broke. Disappointed, we had to forfeit that match. But I didn’t give up. I removed one of the wheels and rewrote the code to operate with only three motors functional. Again we tried to compete, and again another motor appeared to be broken. I removed yet another wheel and stuck a bottle cap as a caster wheel on the back. I rewrote the code, which was running on a little Microchip Technology PIC microcontroller, and programmed the robot to operate with only two wheels working. The crippled robot put up a good fight, but unfortunately it wasn’t enough. I think we scored one goal total, and that was when the robot had just two wheels working.

After the competition, during an interview with the judges, we had a laugh comparing our disabled robot to the videos we took back home with the robot scoring goal after goal. I learned from that incident to always be prepared for the worst, do your best, and sometimes stuff just happens. I’m happy I tried and did my best to fix it, I have no regrets. I have a some of the gears from that robot at home on display as a reminder to always prepare for emergencies and to always try my best.

NAN: What was the last electronics-design related product you purchased and what type of project did you use it with?

ERIC: The last product would be an op-amp I bought, probably the 411 chip. For a current project, I had to generate a –5-to-5-V analog signal from a microcontroller. My temporary solution was to RC filter the PWM output from the op-amp and then use an amplifier with a
gain of 2 and a 2.5-V “virtual ground.” The result is that 2.5 V is the new “zero” voltage. You can achieve –5 V by giving the op-amp 0 V, a –2.5-V difference that is amplified by 2 to yield 5 V. Similarly, 5 V is a 2.5-V difference from the virtual ground, amplified by 2 it provides a 5-V output.

NAN: What do you consider to be the “next big thing” in the industry?

ERIC: I think the next big thing will be personalized health care via smartphones. There are already some insulin pumps and heart monitors that communicate with special smartphone apps via Bluetooth. I think that’s excellent. We have all this computing power in our pockets, we should put it to good use. It would be nice to see these apps educating smartphone users—the patients themselves— about their current health condition. It might inspire patients/users to live healthier lifestyles and take care of themselves. I don’t think the FDA is completely there yet, but I’m excited to see what the future will bring. Remember, the future is what you build it to be.

HackRVA (Richmond, VA, USA)

HackRVA Sign4HackRVA is a Richmond-based makerspace. They like to take things apart, put them back together, figure out how they work, and create new things. Their mission? To learn and make stuff sharing tools and knowledge in technology; including Arduino, Makerbot, Linux, and the Open Source movement.

Aaron Nipper will tell us a little more.

Location 1600 Roseneath Road, Suite E, Richmond, VA 23230
Members 65
Website www.hackrva.org

What’s your meeting space like? 

Our space is about 2,000 square feet. We have an AV and general meeting area, a tech lab, and a fab lab.

What’s in your “toolbox”?

  • Two 3D printers
  • Laser cutter
  • Lots of soldering stations
  • O-scopes
  • Hand and power tools
  • A computer lab

Are there any tools your group really wants or needs?

A CNC Router — like a shopbot. Can’t wait to build that first wiki-house!

Arduino, Raspberry Pi, embedded security… which embedded technologies does your group work with most frequently? 

We use all that stuff. Arduino, R-Pi, whatever we can get our hands on! We’ve designed, from scratch, PCB Badges for RichSec security conference the last three years. Click here to learn more about the PCB Badges project.

What have you been working on lately?

For the past three years, we’ve designed those PCB badges for the RichSec security conference. Here’s another recent build where a member took a Power Wheels and made it Xbox controller driven. Check out the video below or click here to read more about that project.

Do you have any events or initiatives you’d like to tell us about? Where can we learn more about them?

You can learn more about us at hackrva.org. We host the Richmond Maker Guild, have regular Saturday Hackathons, as well as a Noise Night. Members are always coming up with creative events!

Any words of advice for fellow hackers?

My personal motto is fail often, teach others, and post to the web. All those things help me learn and think about projects better.

Want to know more about what HackRVA does? Check out their Facebook page and website.

Show us your hackerspace! Tell us about your group! Where does your group design, hack, create, program, debug, and innovate? Do you work in a 20′ × 20′ space in an old warehouse? Do you share a small space in a university lab? Do you meet a local coffee shop or bar? What sort of electronics projects do you work on? Submit your hackerspace and we might feature you on our website!

Q&A: Raspberry Pi Innovation

Orlando, FL-based web app developer and blogger Shea Silverman recently received Kickstarter funding for the latest version of PiPlay, his Raspberry Pi-based OS. Shea and I discussed his ongoing projects, his Raspberry Pi book, and what’s next for PiPlay.—Nan Price, Associate Editor



Shea Silverman

NAN: What is your current occupation?

SHEA: Web applications developer with the Center for Distributed Learning at the University of Central Florida (UCF).

NAN: Why and when did you decide to start your blog?

SHEA: I’ve been blogging on and off for years, but I could never keep to a schedule or really commit myself to writing. After I started working on side projects, I realized I needed a place to store tips and tricks I had figured out. I installed WordPress, posted some PhoneGap tips, and within a day got a comment from someone who had the same issue, and my tips helped them out. I have been blogging ever since. I make sure to post every Friday night.

NAN: Tell us about PiPlay, the Raspberry Pi OS. Why did you start the OS? What new developments, if any, are you working on?


Shea’s PiPlay Raspberry Pi OS recently reached 400% funding on Kickstarter.

SHEA: PiPlay is a gaming and emulation distribution for the Raspberry Pi single-board computer. It is built on top of the Raspbian OS, and tries to make it as easy as possible to play games on your Raspberry Pi. My blog got really popular after I started posting binaries and tutorials on how to compile different emulators to the Raspberry Pi, but I kept getting asked the same questions and saw users struggling with the same consistent issues.

I decided I would release a disk image with everything preconfigured and ready to be loaded onto an SD card. I’ve been adding new emulators, games, and tools to it ever since.

I just recently completed a Kickstarter that is funding the next release, which includes a much nicer front end, a web GUI, and a better controller configuration system.

NAN: You wrote Instant Raspberry Pi Gaming. Do you consider this book introductory or is it written for the more experienced engineer?

SHEA: Instant Raspberry Pi Gaming is written like a cookbook with recipes for doing various tasks. Some of them are very simple, and they build up to some more advanced recipes. One of the easier tasks is creating your user account on the Pi Store, while the more advanced recipes have you working with Python and using an API to interact with Minecraft.

Readers will learn how to setup a Raspberry Pi, install and use various emulators and games, a bit about the Minecraft API, and common troubleshooting tips.


The Pitroller is a joystick and buttons hooked up to the GPIO pins of a Raspberry Pi, which can act as a controller or keyboard for various emulators.

NAN: You are a member of FamiLAB, an Orlando, FL-based community lab/hackerspace. What types of projects have you worked on at the lab?


Disney director Rich Moore poses with Shea’s miniature arcade machine. The machine was based on Fix It Felix Jr. from Disney’s Wreck It Ralph.

SHEA: I spend a lot of time at the lab using the laser cutter. Creating a 2-D vector in Inkscape, and then watching it be cut out on a piece of wood or acrylic is really inspiring. My favorite project was making a little arcade machine featuring Fix It Felix Jr. from Wreck It Ralph. A marketing person from Disney was able to get it into the hands of the director Rich Moore. He sent me a bunch of pictures of himself holding my little arcade machine next to the full size version.

NAN: Give us a little background information. How did you become interested in technology?

SHEA: My mom always likes to remind me that I’ve been using computers since I was 2. My parents were very interested in technology and encouraged my curiosity when it came to computers. I always liked to take something apart and see how it worked, and then try to put it back together. As the years went on, I’ve devoted more and more time to making technology a major part of my life.

NAN: Tell us about the first embedded system you designed.

SHEA: I have a lot of designs, but I don’t think I’ve ever finished one. I’ll be halfway into a project, learn about something new, then cannibalize what I was working on and repurpose it for my new idea. One of the first embedded projects I worked on was a paintball board made out of a PICAXE microcontroller. I never got it small enough to fit inside the paintball marker, but it was really cool to see everything in action. The best part was when I finally had that “ah-ha!” moment, and everything I was learning finally clicked.

NAN: What was the last electronics-design related product you purchased and what type of project did you use it with?

SHEA: At UCF, one of our teams utilizes a ticket system for dealing with requests. Our department does a hack day each semester, so my coworker and I decided to rig up a system that changes the color of the lights in the office depending on the urgency of requests in the box. We coded up an API and had a Raspberry Pi ping the API every few minutes for updates. We then hooked up two Arduinos to the Raspberry Pi and color-changing LED strips to the Arduinos. We set it up and it’s been working for the past year and a half, alerting the team with different colors when there is work to do.

NAN: Are you currently working on or planning any projects?

SHEA: My Kickstarter for PiPlay just finished at 400% funding. So right now I’m busy working on fulfilling the rewards, and writing the latest version of PiPlay.

NAN: What do you consider to be the “next big thing” in the industry?

SHEA: Wearable computing. Google Glass, the Pebble smart watch, Galaxy Gear—I think these are all great indicators of where our technology is heading. We currently have very powerful computers in our pockets with all kinds of sensors and gadgets built in, but very limited ways to physically interact with them (via the screen, or a keypad). If we can make the input devices modular, be it your watch, a heads-up display, or something else, I think that is going to spark a new revolution in user experiences.