An Organized Space for Programming, Writing, and Soldering

AndersonPhoto1

Photo 1—This is Anderson’s desk when he is not working on any project. “I store all my ‘gear’ in a big plastic bin with several smaller bins inside, which keeps the mess down. I have a few other smaller storage bins as well hidden here and there,” Anderson explained.

AndersonPhoto2

Photo 2—Here is Anderson’s area set up for soldering and running his oscilloscope. “I use a soldering mat to protect my desk surface,” he says. “The biggest issue I have is the power cords from different things getting in my way.”

Al Anderson’s den is the location for a variety of ongoing projects—from programming to writing to soldering. He uses several plastic bins to keep his equipment neatly organized.

Anderson is the IT Director for Salish Kootenai College, a small tribal college based in Pablo, MT. He described some of his workspace features via e-mail:

I work on many different projects. Lately I have been doing more programming. I am getting ready to write a book on the Xojo development system.

Another project I have in the works is using a Raspberry Pi to control my hot tub. The hot tub is about 20 years old, and I want to have better control over what it is doing. Plus I want it to have several features. One feature is a wireless interface that would be accessible from inside the house. The other is a web control of the hot tub so I can turn it on when we are still driving back from skiing to soak my tired old bones.

I am also working on a home yard sprinkler system. I laid some of the pipe last fall and have been working on and off with the controller. This spring I will put in the sprinkler heads and rest of the pipe. I tend to like working with small controllers (e.g., the Raspberry Pi, BeagleBoard’s BeagleBone, and Arduino) and I have a lot of those boards in various states.

Anderson’s article about a Raspberry Pi-based monitoring device will appear in Circuit Cellar’s April issue. You can follow him on Twitter at @skcalanderson.

Arduino-Based DIY Voltage Booster (EE Tip #117)

If your project needs a higher voltage rail than is already available in the circuit, you can use an off-the-shelf step-up device. But when you want a variable output voltage, it’s less easy to find a ready-made IC. However, it’s not complicated to build such a circuit yourself, especially if you have a microcontroller board that’s as easy to program as an Arduino. And this also lets you experiment with the circuit so you can get a better understanding of how it works.

Source: Elektor, April 2010

Source: Elektor, April 2010

No surprises in the circuit—a largely conventional boost converter. The MOSFET is driven by a pulse width modulated (PWM) signal from the microcontroller, and the output voltage is measured by one of the microcontroller’s analog inputs. The driver adjusts the PWM signal according to the difference between the output voltage measured and the voltage wanted.

We don’t have enough space here to go into details about how this circuit works, but it’s worth mentioning a few points of special interest.

The small capacitor across the diode improves the efficiency of the circuit. The load is represented by R3. The components used make it possible to supply over 1 A (current limited by the MSS1260T 683MLB inductor from Coilcraft), but maximum efficiency (89%) is at around 95 mA (at an output voltage of 10 V). To avoid damaging the controller’s analog input (≤5 V), the output voltage may not exceed 24 V. For higher voltages, the values of resistors R1 and R2 would need to be changed.

The MOSFET is driven by the microcontroller, which is nothing but a little Arduino board. The Arduino’s default PWM signal frequency is around 500 Hz—too low for this application, which needs a frequency at least 100 times higher. So we can’t use the PWM functions offered by Arduino. But that’s no problem, as the Arduino can also be programmed in assembler, allowing a maximum frequency of 62.5 kHz (the microcontroller runs at 16 MHz). To sample the output voltage, a frequency of 100 Hz is acceptable, which means we can use Arduino’s standard timers and analog functions. The Arduino serial port is very handy: we can use it for sending the output voltage set point (5–24 V) and for collecting certain information about the operation. Thanks to the Arduino environment, it only took about half an hour to program. Software is available. — Clemens Valens (Elektor, April 2010)

Arduino MOSFET-Based Power Switch

Circuit Cellar columnist Ed Nisley has used Arduino SBCs in many projects over the years. He has found them perfect for one-off designs and prototypes, since the board’s all-in-one layout includes a micrcontroller with USB connectivity, simple connectors, and a power regulator.

But the standard Arduino presents some design limitations.

“The on-board regulator can be either a blessing or a curse, depending on the application. Although the board will run from an unregulated supply and you can power additional circuitry from the regulator, the minute PCB heatsink drastically limits the available current,” Nisley says. “Worse, putting the microcontroller into one of its sleep modes doesn’t shut off the rest of the Arduino PCB or your added circuits, so a standard Arduino board isn’t suitable for battery-powered applications.”

In Circuit Cellar’s January issue, Nisley presents a MOSFET-based power switch that addresses such concerns. He also refers to one of his own projects where it would be helpful.

“The low-resistance Hall effect current sensor that I described in my November 2013 column should be useful in a bright bicycle taillight, but only if there’s a way to turn everything off after the ride without flipping a mechanical switch…,” Nisley says. “Of course, I could build a custom microcontroller circuit, but it’s much easier to drop an Arduino Pro Mini board atop the more interesting analog circuitry.”

Nisley’s January article describes “a simple MOSFET-based power switch that turns on with a push button and turns off under program control: the Arduino can shut itself off and reduce the battery drain to nearly zero.”

Readers should find the article’s information and circuitry design helpful in other applications requiring automatic shutoff, “even if they’re not running from battery power,” Nisley says.

Figure 1: This SPICE simulation models a power p-MOSFET with a logic-level gate controlling the current from the battery to C1 and R2, which simulate a 500-mA load that is far below Q2’s rating. S1, a voltage-controlled switch, mimics an ordinary push button. Q1 isolates the Arduino digital output pin from the raw battery voltage.

Figure 1: This SPICE simulation models a power p-MOSFET with a logic-level gate controlling the current from the battery to C1 and R2, which simulate a 500-mA load that is far below Q2’s rating. S1, a voltage-controlled switch, mimics an ordinary push button. Q1 isolates the Arduino digital output pin from the raw battery voltage.

The article takes readers from SPICE modeling of the circuitry (see Figure 1) through developing a schematic and building a hardware prototype.

“The PCB in Photo 1 combines the p-MOSFET power switch from Figure 2 with a Hall effect current sensor, a pair of PWM-controlled n-MOFSETs, and an Arduino Pro Mini into

The power switch components occupy the upper left corner of the PCB, with the Hall effect current sensor near the middle and the Arduino Pro Mini board to the upper right. The 3-D printed red frame stiffens the circuit board during construction.

Photo 1: The power switch components occupy the upper left corner of the PCB, with the Hall effect current sensor near the middle and the Arduino Pro Mini board to the upper right. The 3-D printed red frame stiffens the circuit board during construction.

a brassboard layout,” Nisley says. “It’s one step beyond the breadboard hairball I showed in my article “Low-Loss Hall Effect Current Sensing” (Circuit Cellar 280, 2013), and will help verify that all the components operate properly on a real circuit board with a good layout.”

For much more detail about the verification process, PCB design, Arduino interface, and more, download the January issue.

The actual circuit schematic includes the same parts as the SPICE schematic, plus the assortment of connectors and jumpers required to actually build the PCB shown in Photo 1.

Figure 2: The actual circuit schematic includes the same parts as the SPICE schematic, as well as the assortment of connectors and jumpers required to actually build the PCB shown in Photo 1.

Open-Source Guide for Embedded Systems Developers (EE Tip #114)

What comes to mind when you hear the term “open source”? Hopefully, it means more to you than just a software application running on a PC.

As an embedded systems developer, you should familiarize yourself with the wide range of open-source programs, programming tools, and hardware platforms currently available. In addition to saving yourself the costs of pricey user licenses, you’ll find that open-source community forums helpful, informative, and engaging.

Open-source software offers a number of advantages. The product is independent of a particular manufacturer and there aren’t license costs. Plus, the product is usually high quality because it is often supported by a large active community of users. When a program’s source code is available, you have the chance to fix errors, change its behavior, and even add new features.

The aforementioned advantages should be good enough reasons for any designer of microcontroller applications to work with open-source software. PC tools such as editors, documentation programs, toolchains (for the vast majority of microcontrollers), operating systems, and libraries are widely available with open-source code.

On the hardware side, open-source microcontroller boards are gaining popularity among serious engineers. The circuits, PCBs, and CAD files are available so you can modify them, improve them, and add more features to meet the demands of your applications. It’s an added benefit that open-source hardware is always supported by software code and libraries that enable you to get up and running fairly quickly.

Since we couldn’t include in the space provided all the open-source resources currently available, we simply list several open-source projects that Elektor and Circuit Cellar engineers and editors recommend.

Below we provide the following lists: hardware; libraries and run-time tools; PC tools, and GNU toolchains. By no means are the lists complete. Still, they’re helpful starting points.

Download your Arduino Uno poster

Click image to download a free Arduino Uno poster

Arduino—This popular platform offers a range of simple microcontroller and development boards that you can purchase from several suppliers. The Arduino website has an active forum and the wide range of software examples will ensure that you are up and running in minimum time.

Openmoko—It’s a complete software stack for a smart. The Neo FreeRunner mobile phone is the target hardware platform. Development and debug boards are also available.

GNU Radio & Universal Software Radio Peripheral—The GNU Radio project is a software toolkit to produce a software-defined radio. The open-source hardware for this project is the Universal Software Radio Peripheral (USRPBoard), which is based on an FPGA.

KiCAD—One of the best-known suites of CAD programs for hardware production, KiCAD includes tools for generating circuit diagrams and PCBs. You can view 3-D representations of the finished board.

Fab Lab—This interesting project offers 3-D laser cutters, 3-D printers, and other machines for use by the general public. It’s a handy resource for making robot parts and art objects.

uIP/lwIP—Two outstanding network stacks, the first is for 8-bit microcontrollers. lwIP is a development of the first and more suited to medium sized controllers. The uIP licence is not so strict allowing the stack to be used in commercial products.

LUFA (formally MyUSB)—A large library of applications for interfacing (both Host and Device) USB enabled AVR controllers. The demonstration applications allow an AVR controller for example to emulate a keyboard and many other devices (mass storage device, audio I/O etc.)OpenSource2

Crypto-avr-lib—It’s a library of optimized cryptographic routines for the Atmel ATmega controller. Issued under the GPL Version 3 licence. Contact the author for other types of licence.

FreeRTOS—FreeRTOS is a lightweight Real Time kernel which can run on many controller families. It can be used in commercial applications and allows the use of closed-source software.

U-Boot—Universal bootloader with a large range of routines for memory, UART interface, SD card, network and USB etc. Conceived originally as a bootloader but now through comprehensive hardware support can be used as the basis of a C code module.

Embedded Filesystems Library—A useful (FAT) file format, when you are short of memory. The GPL licence includes a clause allowing static linking to the library without public disclosure of your code.

.NET Micro Framework—Now open source this very compact, trimmed down .NET Framework running on diverse ARM platforms. Programmable using the object orientated C variant C#; lots of resources including support for I2C, Ethernet and many more. Helps reduce development time.

Eclipse—This is a good development environment. It has a modular structure which makes it very easy to configure. There are around 1,000 plug-in modules (both open source and commercial) for a range of program languages and target systems.

Kdevelop—Kdevelop is an integrated development environment which should satisfy most power-user needs. Runs in MS Windows, Mac OsX, Linux, Solaris and FreeBSD. Plug-in expandable.

Programmer’s Notepad—A lightweight but efficient editor for writing source code. Allows fast, simple and comfortable program production. Can be expanded with plug-ins.

Doxygen—An intelligent tool which can automatically generate code documentation (C, C++, Java etc.). The programmer provides tags in the source file; Doxygen generates the comprehensive documentation in PDF or HTML format. It can also extract the code structure from undocumented source files.

WinMerge—A good tool for code comparison and code synchronization. The program can also compare the contents of folders/files and display the results in a visual text format that makes it easy to understand.

Tera Term—A terminal program to access COM ports, supports Telnet communication Protocol. A debugging tool to eavesdrop on serial communications.

Note: Toolchains for GNU projects are available most processor architectures AVR, Coldfire, ARM, MIPS, PowerPC and Intel x86. The GNU-toolchain includes not only compilers for C, C++ and in most cases also Java (GCC = GNU Compiler Collection), but also Linkers, Assemblers and Debuggers together with C libraries (libc = C library). The tools are used from within other-open source projects, like WinAVR, which provides a familiar user interface to speed up program development.

MCU-Based Projects and Practical Tasks

Circuit Cellar’s January issue presents several microprocessor-based projects that provide useful tools and, in some cases, entertainment for their designers.

Our contributors’ articles in the Embedded Applications issue cover a hand-held PIC IDE, a real-time trailer-monitoring system, and a prize-winning upgrade to a multi-zone audio setup.

Jaromir Sukuba describes designing and building the PP4, a PIC-to-PIC IDE system for programming and debugging a Microchip Technology PIC18. His solar-powered,

The PP4 hand-held PIC-to-PIC programmer

The PP4 hand-held PIC-to-PIC programmer

portable computing device is built around a Digilent chipKIT Max32 development platform.

“While other popular solutions can overshadow this device with better UI and OS, none of them can work with 40 mW of power input and have fully in-house developed OS. They also lack PP4’s fun factor,” Sukuba says. “A friend of mine calls the device a ‘camel computer,’ meaning you can program your favorite PIC while riding a camel through endless deserts.”

Not interested in traveling (much less programming) atop a camel? Perhaps you prefer to cover long distances towing a comfortable RV? Dean Boman built his real-time trailer monitoring system after he experienced several RV trailer tire blowouts. “In every case, there were very subtle changes in the trailer handling in the minutes prior to the blowouts, but the changes were subtle enough to go unnoticed,” he says.

Boman’s system notices. Using accelerometers, sensors, and a custom-designed PCB with a Microchip Technology PIC18F2620 microcontroller, it continuously monitors each trailer tire’s vibration and axle temperature, displays that information, and sounds an alarm if a tire’s vibration is excessive.  The driver can then pull over before a dangerous or trailer-damaging blowout.

But perhaps you’d rather not travel at all, just stay at home and listen to a little music? This issue includes Part 1 of Dave Erickson’s two-part series about upgrading his multi-zone home audio system with an STMicroelectronics STM32F100 microprocessor, an LCD, and real PC boards. His MCU-controlled, eight-zone analog sound system won second-place in a 2011 STMicroelectronics design contest.

In addition to these special projects, the January issue includes our columnists exploring a variety of  EE topics and technologies.

Jeff Bachiochi considers RC and DC servomotors and outlines a control mechanism for a DC motor that emulates a DC servomotor’s function and strength. George Novacek explores system safety assessment, which offers a standard method to identify and mitigate hazards in a designed product.

Ed Nisley discusses a switch design that gives an Arduino Pro Mini board control over its own power supply. He describes “a simple MOSFET-based power switch that turns on with a push button and turns off under program control: the Arduino can shut itself off and reduce the battery drain to nearly zero.”

“This should be useful in other applications that require automatic shutoff, even if they’re not running from battery power,” Nisley adds.

Ayse K. Coskun discusses how 3-D chip stacking technology can improve energy efficiency. “3-D stacked systems can act as energy-efficiency boosters by putting together multiple chips (e.g., processors, DRAMs, other sensory layers, etc.) into a single chip,” she says. “Furthermore, they provide high-speed, high-bandwidth communication among the different layers.”

“I believe 3-D technology will be especially promising in the mobile domain,” she adds, “where the data access and processing requirements increase continuously, but the power constraints cannot be pushed much because of the physical and cost-related constraints.”

Arduino Uno Blueprint — Free Download

Elektor.Labs recently produced an Arduino Uno blueprint poster for element14. The poster details everything you need to know about the Arduino Uno.

Download it for free here.

Download your Arduino Uno poster

Download your Arduino Uno poster

The poster also includes coding notes that will get you working with your Arduino Uno in no time.

About the Arduino Uno:

  • Core Architecture: AVR
  • Core Sub-Architecture: megaAVR
  • Silicon Core: ATmega328
  • Features: The Arduino Uno is powered via USB or an external supply. It’s programmed with Arduino software.

Recent Arduino-related articles from Circuit Cellar:

 

Client Profile: Digi International, Inc

Contact: Elizabeth Presson
elizabeth.presson@digi.com

Featured Product: The XBee product family (www.digi.com/xbee) is a series of modular products that make adding wireless technology easy and cost-effective. Whether you need a ZigBee module or a fast multipoint solution, 2.4 GHz or long-range 900 MHz—there’s an XBee to meet your specific requirements.

XBee Cloud Kit

Digi International XBee Cloud Kit

Product information: Digi now offers the XBee Wi-Fi Cloud Kit (www.digi.com/xbeewificloudkit) for those who want to try the XBee Wi-Fi (XB2B-WFUT-001) with seamless cloud connectivity. The Cloud Kit brings the Internet of Things (IoT) to the popular XBee platform. Built around Digi’s new XBee Wi-Fi
module, which fully integrates into the Device Cloud by Etherios, the kit is a simple way for anyone with an interest in M2M and the IoT to build a hardware prototype and integrate it into an Internet-based application. This kit is suitable for electronics engineers, software designers, educators, and innovators.

Exclusive Offer: The XBee Wi-Fi Cloud Kit includes an XBee Wi-Fi module; a development board with a variety of sensors and actuators; loose electronic prototyping parts to make circuits of your own; a free subscription to Device Cloud; fully customizable widgets to monitor and control connected devices; an open-source application that enables two-way communication and control with the development board over the Internet; and cables, accessories, and everything needed to connect to the web. The Cloud Kit costs $149.

Low-Cost SBCs Could Revolutionize Robotics Education

For my entire life, my mother has been a technology trainer for various educational institutions, so it’s probably no surprise that I ended up as an engineer with a passion for STEM education. When I heard about the Raspberry Pi, a diminutive $25 computer, my thoughts immediately turned to creating low-cost mobile computing labs. These labs could be easily and quickly loaded with a variety of programming environments, walking students through a step-by-step curriculum to teach them about computer hardware and software.

However, my time in the robotics field has made me realize that this endeavor could be so much more than a traditional computer lab. By adding actuators and sensors, these low-cost SBCs could become fully fledged robotic platforms. Leveraging the common I2C protocol, adding chains of these sensors would be incredibly easy. The SBCs could even be paired with microcontrollers to add more functionality and introduce students to embedded design.

rover_webThere are many ways to introduce students to programming robot-computers, but I believe that a web-based interface is ideal. By setting up each computer as a web server, students can easily access the interface for their robot directly though the computer itself, or remotely from any web-enabled device (e.g., a smartphone or tablet). Through a web browser, these devices provide a uniform interface for remote control and even programming robotic platforms.

A server-side language (e.g., Python or PHP) can handle direct serial/I2C communications with actuators and sensors. It can also wrap more complicated robotic concepts into easily accessible functions. For example, the server-side language could handle PID and odometry control for a small rover, then provide the user functions such as “right, “left,“ and “forward“ to move the robot. These functions could be accessed through an AJAX interface directly controlled through a web browser, enabling the robot to perform simple tasks.

This web-based approach is great for an educational environment, as students can systematically pull back programming layers to learn more. Beginning students would be able to string preprogrammed movements together to make the robot perform simple tasks. Each movement could then be dissected into more basic commands, teaching students how to make their own movements by combining, rearranging, and altering these commands.

By adding more complex commands, students can even introduce autonomous behaviors into their robotic platforms. Eventually, students can be given access to the HTML user interfaces and begin to alter and customize the user interface. This small superficial step can give students insight into what they can do, spurring them ahead into the next phase.
Students can start as end users of this robotic framework, but can eventually graduate to become its developers. By mapping different commands to different functions in the server side code, students can begin to understand the links between the web interface and the code that runs it.

Kyle Granat

Kyle Granat, who wrote this essay for Circuit Cellar,  is a hardware engineer at Trossen Robotics, headquarted in Downers Grove, IL. Kyle graduated from Purdue University with a degree in Computer Engineering. Kyle, who lives in Valparaiso, IN, specializes in embedded system design and is dedicated to STEM education.

Students will delve deeper into the server-side code, eventually directly controlling actuators and sensors. Once students begin to understand the electronics at a much more basic level, they will be able to improve this robotic infrastructure by adding more features and languages. While the Raspberry Pi is one of today’s more popular SBCs, a variety of SBCs (e.g., the BeagleBone and the pcDuino) lend themselves nicely to building educational robotic platforms. As the cost of these platforms decreases, it becomes even more feasible for advanced students to recreate the experience on many platforms.

We’re already seeing web-based interfaces (e.g., ArduinoPi and WebIOPi) lay down the beginnings of a web-based framework to interact with hardware on SBCs. As these frameworks evolve, and as the costs of hardware drops even further, I’m confident we’ll see educational robotic platforms built by the open-source community.

I/O Raspberry Pi Expansion Card

The RIO is an I/O expansion card intended for use with the Raspberry Pi SBC. The card stacks on top of a Raspberry Pi to create a powerful embedded control and navigation computer in a small 20-mm × 65-mm × 85-mm footprint. The RIO is well suited for applications requiring real-world interfacing, such as robotics, industrial and home automation, and data acquisition and control.

RoboteqThe RIO adds 13 inputs that can be configured as digital inputs, 0-to-5-V analog inputs with 12-bit resolution, or pulse inputs capable of pulse width, duty cycle, or frequency capture. Eight digital outputs are provided to drive loads up to 1 A each at up to 24 V.
The RIO includes a 32-bit ARM Cortex M4 microcontroller that processes and buffers the I/O and creates a seamless communication with the Raspberry Pi. The RIO processor can be user-programmed with a simple BASIC-like programming language, enabling it to perform logic, conditioning, and other I/O processing in real time. On the Linux side, RIO comes with drivers and a function library to quickly configure and access the I/O and to exchange data with the Raspberry Pi.

The RIO features several communication interfaces, including an RS-232 serial port to connect to standard serial devices, a TTL serial port to connect to Arduino and other microcontrollers that aren’t equipped with a RS-232 transceiver, and a CAN bus interface.
The RIO is available in two versions. The RIO-BASIC costs $85 and the RIO-AHRS costs $175.

Roboteq, Inc.
www.roboteq.com

Arduino-Based Hand-Held Gaming System

gameduino2-WEBJames Bowman, creator of the Gameduino game adapter for microcontrollers, recently made an upgrade to the system adding a Future Technology Devices International (FTDI) FT800 chip to drive the graphics. Associate Editor Nan Price interviewed James about the system and its capabilities.

NAN: Give us some background. Where do you live? Where did you go to school? What did you study?

Bowman-WEB

James Bowman

 JAMES: I live on the California coast in a small farming village between Santa Cruz and San Francisco. I moved here from London 17 years ago. I studied computing at Imperial College London.

NAN: What types of projects did you work on when you were employed by Silicon Graphics, 3dfx Interactive, and NVIDIA?

JAMES: Always software and hardware for GPUs. I began in software, which led me to microcode, which led to hardware. Before you know it you’ve learned Verilog. I was usually working near the boundary of software and hardware, optimizing something for cost, speed, or both.

NAN: How did you come up with the idea for the Gameduino game console?

JAMES: I paid for my college tuition by working as a games programmer for Nintendo and Sega consoles, so I was quite familiar with that world. It seemed a natural fit to try to give the Arduino some eye-catching color graphics. Some quick experiments with a breadboard and an FPGA confirmed that the idea was feasible.

NAN: The Gameduino 2 turns your Arduino into a hand-held modern gaming system. Explain the difference from the first version of Gameduino—what upgrades/additions have been made?

Gameduinofinal-WEB

The Gameduino2 uses a Future Technology Devices International chip to drive its graphics

JAMES: The original Gameduino had to use an FPGA to generate graphics, because in 2011 there was no such thing as an embedded GPU. It needs an external monitor and you had to supply your own inputs (e.g., buttons, joysticks, etc.). The Gameduino 2 uses the new Future Technology Devices International (FTDI) FT800 chip, which drives all the graphics. It has a built-in color resistive touchscreen and a three-axis accelerometer. So it is a complete game system—you just add the CPU.

NAN: How does the Arduino factor into the design?

GameduinoPCB-WEB

An Arduino, Ethernet adapter, and a Gameduino

 JAMES: Arduino is an interesting platform. It is 5 V, believe it or not, so the design needs a level shifter. Also, the Arduino is based on an 8-bit microcontroller, so the software stack needs to be carefully built to provide acceptable performance. The huge advantage of the Arduino is that the programming environment—the IDE, compiler, and downloader—is used and understood by hundreds of thousands of people.

 NAN: Is it easy or possible to customize the Gameduino 2?

 JAMES: I would have to say no. The PCB itself is entirely surface mount technology (SMT) and all the ICs are QFNs—they have no accessible pins! This is a long way from the DIP packages of yesterday, where you could change the circuit by cutting tracks and soldering onto the pins.

I needed a microscope and a hot air station to make the Gameduino2 prototype. That is a long way from the “kitchen table” tradition of the Arduino. Fortunately the Arduino’s physical design is very customization-friendly. Other devices can be stacked up, adding networking, hi-fi sound, or other sensor inputs.

 NAN: The Gameduino 2 project is on Kickstarter through November 7, 2013. Why did you decide to use Kickstarter crowdfunding for this project?

 JAMES: Kickstarter is great for small-scale inventors. The audience it reaches also tends to be interested in novel, clever things. So it’s a wonderful way to launch a small new product.

NAN: What’s next for Gameduino 2? Will the future see a Gameduino 3?

 JAMES: Product cycles in the Arduino ecosystem are quite long, fortunately, so a Gameduino 3 is distant. For the Gameduino 2, I’m writing a book, shipping the product, and supporting the developer community, which will hopefully make use of it.

 

Designing Wireless Data Gloves

Kevin Marinelli, IT manager for the Mathematics Department at the University of Connecticut, recently answered CC.Post’s newsletter invitation to readers to tell us about their wearable electronics projects. Kevin exhibited his project,  “Wireless Data Gloves,” at the World Maker Faire New York in September. He spoke with Circuit Cellar Managing Editor Mary Wilson about the gloves, which are based on an Adafruit ATmega32U4 breakout board, use XBee modules for wireless communication, and enable wearers to visually manipulate data and 3-D graphics.

MARY: Tell us a little bit about yourself and your educational and professional background.

KEVIN: I am originally from Sydney, Nova Scotia, in Canada. From an early age I have

Kevin Marinelli

Kevin Marinelli

always been interested in taking things apart and creating new things. My degrees are a Bachelor’s in Computer Science from Dalhousie University in Halifax, Nova Scotia, and a Master’s in Computer Science from the University of New Brunswick in Fredericton, New Brunswick. I am currently working on my PhD in Computer Science at the University of Connecticut (UConn).

My first full-time employment was with ITS (the computer center) at Dalhousie University. After eight years, I moved on to an IT management position the Ocean Mapping Group at the University of New Brunswick. I am currently the IT manager for the Mathematics Department at  UConn.

I am also an active member of MakeHartford, which is a local group of makers in Hartford, Connecticut.

MARY: Describe the wireless data gloves you recently exhibited at the World Maker Faire in New York. What inspired the idea?

KEVIN: The idea was initially inspired 20 years ago when using a Polhemus 6 Degree-of-Freedom sensor for manipulating computer graphics when I was at the University of New Brunswick. The device used magnetic fields to locate a sensor in three-dimensional space and detect its orientation. The combined location and orientation data provides data with six degrees of freedom. I have been interested in creating six degrees of freedom input devices ever since. With the Arduino and current sensor technologies, that is now possible.

Wireless data gloves on display at World Maker Faire New York. (Photo: Rohit Mehta)

Wireless data gloves on display at World Maker Faire New York. (Photo: Rohit Mehta)

MARY: What do the gloves do? What applications are there? Can you provide an example of who might use them and for what purpose?

KEVIN: The data gloves allow me to use my hands to wirelessly transmit telemetry data to a base station computer, which collects the data and provides it to any application programs that need it.

There are a number of potential applications, such as manipulating 3-D computer graphics, measurement of data for medical applications, remote control of vehicles, remote control of animatronics and puppetry.

MARY: Can you tell me about the data gloves’s design and the components used?

KEVIN: The basic design guidelines were to make the gloves self-contained, lightweight, easy to program, wireless, and rechargeable. The main electronic components are an Adafruit ATmega32U4 breakout board  (Arduino Leonardo software compatible), a SparkFun 9d0f sensor board, an XBee Pro packet radio, a LiPo battery charger circuit, and a LiPo battery. These are all open hardware projects or, in the case of the battery, are ordinary consumer products.

The choice of the ATMega32U4 for the processor was made to provide a USB port without any external components such as an FTDI chip to convert between serial and USB communications. This frees up the serial port on the processor for communicating with the XBee radio.

For the sensors, the SparkFun 9dof board was perfect because of its miniscule size and

Top of glove

Top of glove

because it only requires four connections: two connections for power and two connections for I2C. The board has components with readily available data sheets, and there is access to working example code for the sensor board. This reduced the design work greatly by using an off-the-shelf product instead of designing one myself.

The choice of an 800-mAh LiPo battery provides an excellent lightweight rechargeable power supply in a small form factor. The relatively small battery powers the project for more than 24 h of continuous use.

Palm of glove

Palm of glove

A simple white cotton glove acts as the structure to mount the electronics. For user-controlled input, the glove has conductive fabric fingertips and palm. Touching a finger to the thumb, or the pad on the palm, closes an electrical pathway, which allows the microcontroller to detect the input.

For user-selectable input, each fingertip and the palm of the hand has a conductive fabric pad connected to the Adafruit microcontroller. The thumb and palm act as a voltage source, while the fingertips act as inputs to the microcontroller. This way, the microcontroller can detect which fingers are touching the thumb and the palm pads. Insulated wires of 30 gauge phosphor bronze are sewn into the glove to connect the pads to the microcontroller.

MARY: Are the gloves finished? What were some of the design challenges? Do you plan any changes to the design?

KEVIN: The initial glove design and second version of the prototype have been completed. The major design challenges were finding a microcontroller board with sufficient capabilities to fit on the back of a hand, and configuring the XBee radios. The data glove design will continue to evolve over the next year as newer and more compact components become available.

Initially I was designing and building my own microcontroller circuit based on the ATmega32U4, but Adafruit came out with a nice, usable, designed board for my needs. So I changed the design to use their board.

SparkFun has a well-designed micro USB-based LiPo battery charger circuit. This would have been ideal for my project except that it does not have an On/Off switch and only has some through-hole solder points for powering an external project. I used their CadSoft EAGLE files to redesign the circuit to make it slightly more compact, added in a power switch and a JST connector for the power output for projects.

The XBee radios were an interesting challenge on their own. My initial design used the standard XBee, but that caused communication complications when using multiple data gloves simultaneously. In reading Robert Faludi’s book Building Wireless Sensor Networks: With ZigBee, XBee, Arduino, and Processing, I learned that the XBee Pro was more suited to my needs because it could be configured on a private area network (PAN) with end-nodes for the data gloves and a coordinator for the base station.

One planned future change is to switch to the surface-mount version of the XBee Pro. This will reduce both the size and weight of the electronics for the project.

The current significant design challenge I am working on is how to prevent metal fatigue in the phosphor bronze wires as they bend when the hand and fingers flex. The fatigue problem occurs because I use a small diamond file to remove the Kapton insulation on the wires. This process introduces small nicks or makes the wires too thin, which then promotes the metal fatigue.

A third version is in the design stage. The new design will replace the SparkFun 9dof board with a smaller single-chip sensor, which I hope can be mounted directly on the Adafruit ATmega32U4 board.

MARY: What new skills or technologies did you learn from the project, if any?

KEVIN: Along the way to creating the gloves, I learned a great deal about modern electronics. My previous skills in electronics were learned in the ’70s with single-sided circuits with through-hole components and pre-made circuit boards. I can now design and create double-sided circuit boards with primarily surface-mounted components. For initial prototype designs, I use double-sided photosensitized circuit boards and etch them at home.

Learning to program Arduino boards and Arduino clones has been incredible. The fact that the boards can be programmed using C in a nice IDE with lots of support libraries for common programming tasks makes the platform an incredibly efficient tool. Having an enormous following makes it very easy to find technical support for solving problems with Arduino products and making Arduino clones.

Wireless networking is a key component for the success of the project. I was lucky to have a course in wireless sensor network design at UConn, which taught me how to leverage wireless technology and avoid many of the pitfalls. That, combined with some excellent reference books I found, insured that the networking is stable. The network design provides for more network bandwidth than a single pair of data gloves require, so it is feasible to have multiple people collaborating manipulating the same on the same project.

Designing microcontroller circuits using EAGLE has been an interesting experience. While most of the new components I use regularly in designs are available in libraries from Adafruit and SparkFun, I occasionally have to design my own parts in EAGLE. Using EAGLE to its fullest potential will still take some time, but I have become reasonably proficient with it.

For soldering, I mostly still use a standard temperature controlled soldering iron with a standard tip. Amazingly, this allows me to solder 0402 resistors and capacitors and up to 100 pitch chips. When I have components that need to be soldered under the surface, I use solder paste and a modified electric skillet. This allows me to directly control the temperature of the soldering and gives me direct access to monitoring the process.

The battery charger circuit on my data glove is hand soldered and has a number of 0402-sized components, as  well as a micro USB connector, which also is a challenge to hand solder properly.

MARY: Are there similar “data gloves” out there? How are yours different?

There are a number of data glove projects, which can be found on the Internet. Some are commercial products, while others are academic projects.

My gloves are unique in that they are lightweight and self-contained on the cotton glove. All other projects that you can find on the Internet are either hard-wired to a computer or have components such as the microcontroller, batteries, or radio strapped to the arm or body.

Also, because the main structure is a self-contained cotton glove; the gloves do not interfere with other activities such as typing on a keyboard, using a mouse, writing with a pen, or even drinking from a glass. This was quite handy when developing the software for the glove because I could test the software and make programming corrections without having the inconvenience of putting the gloves on and taking them off repeatedly.

MARY: Are you working on any other projects you’d like to briefly tell us about?

KEVIN: At UConn, we are lucky to have one of the few academic programs in puppetry in the US. In the spring, I plan on taking a fine arts course at UConn in designing and making marionette puppets. This will allow me to expand the use of my data gloves into controlling and manipulating puppets for performance art.

I am collaborating on designing circuit boards with a number of people in Hartford. The more interesting collaborations are with artists, where they think differently about technology than I do. Balam Soto of Open Wire Labs is a new media artist and one of the creative artists I collaborate with regularly. He is also a member of MakeHartford and presents at Maker Faires.

MARY: What was the response to the wireless data gloves at World Maker Faire New York?

KEVIN: The response to the data gloves was overwhelmingly positive. People were making comparisons to the Nintendo Power Glove and to the movie “Minority Report.” Several musicians commented that the gloves should be excellent for performing and recording virtual musical instruments such as a guitar, trumpet and drums.

For the demonstration, I showed a custom application; which allowed both hands (or two people) to interactively manipulate points and lines on a drawing. Many people were encouraged to use the gloves for themselves, which enhanced the quality of the feedback I received.

The gloves are large-sized to fit my hands, which was quite a challenge for younger children to use because their hands were “lost” in the gloves. Even with the size challenge, it was fun watching younger children manipulating the objects on the computer screen.

I look forward to the Maker Faire next year, when I will have implemented the newer design for the data gloves and will have additional software to demonstrate. I plan on trying to put together a presentation on some form of performance art using the data gloves.

Client Profile: Pololu Robotics

Pololu Robotics
www.pololu.com
920 Pilot Road
Las Vegas, NV 89119

Contact: inbox@pololu.com

Pololu Robotics Zumo

Pololu Robotics Zumo

Embedded Products/Services: Pololu designs, manufactures, and distributes a variety of robotic and electronic parts. Get the building blocks for your next project at Pololu, where you can find wheels, motors, motion controllers, basic prototyping supplies, sensors, complete robot kits, and more. Pololu also offers a custom laser cutting service starting at $25.

Product information: The Pololu Zumo robot is an Arduino-controllable tracked robot platform that measures less than 10 cm × 10 cm, which is small enough to qualify for Mini Sumo. The Zumo includes two micro-metal gearmotors coupled to a pair of silicone tracks, a stainless steel bulldozer-style blade, six infrared reflectance sensors for line following or edge detection, a three-axis accelerometer and magnetometer, and a buzzer for simple sounds and music. A kit version is also available.

Exclusive offer: Use coupon code ZUMOCC20 for 20% off any one item in Pololu’s Zumo category (www.pololu.com/zumo).

Small Plug-In Embedded Cellular Modem

Skywire plug-in modem

Skywire plug-in modem

The Skywire is a small plug-in embedded cellular modem. It uses a standard XBee form factor and 1xRTT CDMA operating mode to help developers minimize hardware and network costs. Its U.FL port ensures antenna flexibility.

The Skywire modem features a Telit CE910-DUAL wireless module and is available with bundled CDMA 1xRTT data plans from leading carriers, enabling developers to add fully compliant cellular connectivity without applying for certification. Future versions of the Skywire will support GSM and LTE. Skywire is smaller than many other embedded solutions and simple to deploy due to its bundled carrier service plans.

Skywire is available with a complete development kit that includes the cellular modem, a baseboard, an antenna, a power supply, debug cables, and a cellular service plan. The Skywire baseboard is an Arduino shield, which enables direct connection to an Arduino microcontroller.

Skywire modems cost $129 individually and $99 for 1,000-unit quantities. A complete development kit including the modem costs $262.

NimbeLink, LLC
www.nimbelink.com

Q&A: Jeremy Blum, Electrical Engineer, Entrepreneur, Author

Jeremy Blum

Jeremy Blum

Jeremy Blum, 23, has always been a self-proclaimed tinkerer. From Legos to 3-D printers, he has enjoyed learning about engineering both in and out of the classroom. A recent Cornell University College of Engineering graduate, Jeremy has written a book, started his own company, and traveled far to teach children about engineering and sustainable design. Jeremy, who lives in San Francisco, CA, is now working on Google’s Project Glass.—Nan Price, Associate Editor

NAN: When did you start working with electronics?

JEREMY: I’ve been tinkering, in some form or another, ever since I figured out how to use my opposable thumbs. Admittedly, it wasn’t electronics from the offset. As with most engineers, I started with Legos. I quickly progressed to woodworking and I constructed several pieces of furniture over the course of a few years. It was only around the start of my high school career that I realized the extent to which I could express my creativity with electronics and software. I thrust myself into the (expensive) hobby of computer building and even built an online community around it. I financed my hobby through my two companies, which offered computer repair services and video production services. After working exclusively with computer hardware for a few years, I began to dive deeper into analog circuits, robotics, microcontrollers, and more.

NAN: Tell us about some of your early, pre-college projects.

JEREMY: My most complex early project was the novel prosthetic hand I developed in high school. The project was a finalist in the prestigious Intel Science Talent Search. I also did a variety of robotics and custom-computer builds. The summer before starting college, my friends and I built a robot capable of playing “Guitar Hero” with nearly 100% accuracy. That was my first foray into circuit board design and parallel programming. My most ridiculous computer project was a mineral oil-cooled computer. We submerged an entire computer in a fish tank filled with mineral oil (it was actually a lot of baby oil, but they are basically the same thing).

DeepNote Guitar Hero Robot

DeepNote Guitar Hero Robot

Mineral Oil-Cooled Computer

Mineral Oil-Cooled Computer

NAN: You’re a recent Cornell University College of Engineering graduate. While you were there, you co-founded Cornell’s PopShop. Tell us about the workspace. Can you describe some PopShop projects?

Cornell University's PopShop

Cornell University’s PopShop

JEREMY: I recently received my Master’s degree in Electrical and Computer Engineering from Cornell University, where I previously received my BS in the same field. During my time at Cornell, my peers and I took it upon ourselves to completely retool the entrepreneurial climate at Cornell. The PopShop, a co-working space that we formed a few steps off Cornell’s main campus, was our primary means of doing this. We wanted to create a collaborative space where students could come to explore their own ideas, learn what other entrepreneurial students were working on, and get involved themselves.

The PopShop is open to all Cornell students. I frequently hosted events there designed to get more students inspired about pursuing their own ideas. Common occurrences included peer office hours, hack-a-thons, speed networking sessions, 3-D printing workshops, and guest talks from seasoned venture capitalists.

Student startups that work (or have worked) out of the PopShop co-working space include clothing companies, financing companies, hardware startups, and more. Some specific companies include Rosie, SPLAT, LibeTech (mine), SUNN (also mine), Bora Wear, Yorango, Party Headphones, and CoVenture.

NAN: Give us a little background information about Cornell University Sustainable Design (CUSD). Why did you start the group? What types of CUSD projects were you involved with?

CUSD11JEREMY: When I first arrived at Cornell my freshman year, I knew right away that I wanted to join a research lab, and that I wanted to join a project team (knowing that I learn best in hands-on environments instead of in the classroom). I joined the Cornell Solar Decathlon Team, a very large group of mostly engineers and architects who were building a solar-powered home to enter in the biannual solar decathlon competition orchestrated by the Department of Energy.

By the end of my freshman year, I was the youngest team leader in the organization.  After competing in the 2009 decathlon, I took over as chief director of the team and worked with my peers to re-form the organization into Cornell University Sustainable Design (CUSD), with the goal of building a more interdisciplinary team, with far-reaching impacts.

CUSD3

Under my leadership, CUSD built a passive schoolhouse in South Africa (which has received numerous international awards), constructed a sustainable community in Nicaragua, has been the only student group tasked with consulting on sustainable design constraints for Cornell’s new Tech Campus in New York City, partnered with nonprofits to build affordable homes in upstate New York, has taught workshops in museums and school, contributed to the design of new sustainable buildings on Cornell’s Ithaca campus, and led a cross-country bus tour to teach engineering and sustainability concepts at K–12 schools across America. The group is now comprised of students from more than 25 different majors with dozens of advisors and several simultaneous projects. The new team leaders are making it better every day. My current startup, SUNN, spun out of an EPA grant that CUSD won.

CUSD7NAN: You spent two years working at MakerBot Industries, where you designed electronics for a 3-D printer and a 3-D scanner. Any highlights from working on those projects?

JEREMY: I had a tremendous opportunity to learn and grow while at MakerBot. When I joined, I was one of about two dozen total employees. Though I switched back and forth between consulting and full-time/part-time roles while class was in session, by the time I stopped working with MakerBot (in January 2013), the company had grown to more than 200 people. It was very exciting to be a part of that.

I designed all of the electronics for the original MakerBot Replicator. This constituted a complete redesign from the previous electronics that had been used on the second generation MakerBot 3-D printer. The knowledge I gained from doing this (e.g., PCB design, part sourcing, DFM, etc.) drastically outweighed much of what I had learned in school up to that point. I can’t say much about the 3-D scanner (the MakerBot Digitizer), as it has been announced, but not released (yet).

The last project I worked on before leaving MakerBot was designing the first working prototype of the Digitizer electronics and firmware. These components comprised the demo that was unveiled at SXSW this past April. This was a great opportunity to apply lessons learned from working on the Replicator electronics and find ways in which my personal design process and testing techniques could be improved. I frequently use my MakerBot printers to produce custom mechanical enclosures that complement the open-source electronics projects I’ve released.

NAN: Tell us about your company, Blum Idea Labs. What types of projects are you working on?

JEREMY: Blum Idea Labs is the entity I use to brand all my content and consulting services. I primarily use it as an outlet to facilitate working with educational organizations. For example, the St. Louis Hacker Scouts, the African TAHMO Sensor Workshop, and several other international organizations use a “Blum Idea Labs Arduino curriculum.” Most of my open-source projects, including my tutorials, are licensed via Blum Idea Labs. You can find all of them on my blog (www.jeremyblum.com/blog). I occasionally offer private design consulting through Blum Idea Labs, though I obviously can’t discuss work I do for clients.

NAN: Tell us about the blog you write for element14.

JEREMY: I generally use my personal blog to write about projects that I’ve personally been working on.  However, when I want to talk about more general engineering topics (e.g., sustainability, engineering education, etc.), I post them on my element14 blog. I have a great working relationship with element14. It has sponsored the production of all my Arduino Tutorials and also provided complete parts kits for my book. We cross-promote each-other’s content in a mutually beneficial fashion that also ensures that the community gets better access to useful engineering content.

NAN: You recently wrote Exploring Arduino: Tools and Techniques for Engineering Wizardry. Do you consider this book introductory or is it written for the more experienced engineer?

JEREMY: As with all the video and written content that I produce on my website and on YouTube, I tried really hard to make this book useful and accessible to both engineering veterans and newbies. The book builds on itself and provides tons of optional excerpts that dive into greater technical detail for those who truly want to grasp the physics and programming concepts behind what I teach in the book. I’ve already had readers ranging from teenagers to senior citizens comment on the applicability of the book to their varying degrees of expertise. The Amazon reviews tell a similar story. I supplemented the book with a lot of free digital content including videos, part descriptions, and open-source code on the book website.

NAN: What can readers expect to learn from the book?

JEREMY: I wrote the book to serve as an engineering introduction and as an idea toolbox for those wanting to dive into concepts in electrical engineering, computer science, and human-computer interaction design. Though Exploring Arduino uses the Arduino as a platform to experiment with these concepts, readers can expect to come away from the book with new skills that can be applied to a variety of platforms, projects, and ideas. This is not a recipe book. The projects readers will undertake throughout the book are designed to teach important concepts in addition to traditional programming syntax and engineering theories.

NAN: I see you’ve spent some time introducing engineering concepts to children and teaching them about sustainable engineering and renewable energy. Tell us about those experiences. Any highlights?

JEREMY: The way I see it, there are two ways in which engineers can make the world a better place: they can design new products and technologies that solve global problems or they can teach others the skills they need to assist in the development of solutions to global problems. I try hard to do both, though the latter enables me to have a greater impact, because I am able to multiply my impact by the number of students I teach. I’ve taught workshops, written curriculums, produced videos, written books, and corresponded directly with thousands of students all around the world with the goal of transferring sufficient knowledge for these students to go out and make a difference.

Here are some highlights from my teaching work:

bluestamp

I taught BlueStamp Engineering, a summer program for high school students in NYC in the summer of 2012. I also guest-lectured at the program in 2011 and 2013.

I co-organized a cross-country bus tour where we taught sustainability concepts to school children across the country.

indiaI was invited to speak at Techkriti 2013 in Kanpur, India. I had the opportunity to meet many students from IIT Kanpur who already followed my videos and used my tutorials to build their own projects.

Blum Idea Labs partnered with the St. Louis Hacker Scouts to construct a curriculum for teaching electronics to the students. Though I wasn’t there in person, I did welcome them all to the program with a personalized video.

brooklyn_childrens_zoneThrough CUSD, I organized multiple visits to the Brooklyn Children’s Zone, where my team and I taught students about sustainable architecture and engineering.

Again with CUSD, we visited the Intrepid museum to teach sustainable energy concepts using potato batteries.

intrepid

NAN: Speaking of promoting engineering to children, what types of technologies do you think will be important in the near future?

JEREMY: I think technologies that make invention more widely accessible are going to be extremely important in the coming years. Cheaper tools, prototyping platforms such as the Arduino and the Raspberry Pi, 3-D printers, laser cutters, and open developer platforms (e.g., Android) are making it easier than ever for any person to become an inventor or an engineer.  Every year, I see younger and younger students learning to use these technologies, which makes me very optimistic about the things we’ll be able to do as a society.

Maker Faire in Rome Highlights Big News For Arduino Fans

If you like working on Arduino projects, you probably welcome some big news on two Linux-capable boards that came out of the recent Maker Faire in Rome.

Arduino founder Massimo Banzi announced a new collaboration with Intel called the Intel Galileo, an Arduino-compatible microcontroller board that uses Intel’s 32-bit Pentium-class

Arduino

Arduino

processors.

With the Galileo’s small, 32-bit Quark processor, the collaboration gives Intel a toehold in the low-power device market, while providing Arduino-compatible boards that have more processing power. (Arduino devices currently use Atmel’s 8-bit microcontrollers.)

An October 3 Arduino blog post by Zoe Romano says the Galileo is “a great tool for quickly prototyping simple interactive designs like LED light displays that respond to social media, or for tackling more complex projects from automating home appliances to building life-size robots that you control from your smartphone.”

Also at the Maker Faire, Banzi and Texas Instruments spokesmen discussed their collaboration on Arduino TRE, a next-generation Arduino SBC based on TI’s Sitara AM335x ARM Cortex-A8 processor.

Arduino TRE is the “most powerful Arduino to date” and will be able to run full Linux, according to another Arduino blog post by Romano.

“Arduino developers will get up to 100 times more performance with the Sitara-processor-based TRE than they do on the Arduino Leonardo or Uno,”  Romano says. For example, the Linux Arduino will be able to run high-speed communications and high-performance desktop applications.

Intel may be closely  following  news about the Arduino TRE, Stephen Shankland suggests in his October 5 article on the c/net website.

“The Arduino Tre speed boost comes from its Texas Instruments Sitara AM335x processor, which is based on the Cortex-A8 design from ARM Holdings,” Shankland’s article says. “Because ARM chips are nearly universal in the smartphone market that Intel has been struggling to penetrate, they’re a top competitive concern for Intel, and TI’s move means it might not be Intel’s Pentium-derived Quark chips that hobbyists end up with when looking for their next widget.”

However the competition plays out, it all seems nothing but good news for electronics tinkerers, hardware hackers, hobbyists, and designers who want more choices and more processing power for their Arduino-based projects.