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Archive: Electronics

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January 4, 2009

BaR2D2 - mobile droid bartender

After a long day on Tatooine fighting off Sandpeople and haggling over the price of power converters, Obi-Wan and Luke Skywalker walk into a droid...

BaR2D2 is a radio-controlled, mobile bar that features a motorized beer elevator, motorized ice/mixer drawer, six-bottle shot dispenser, and sound activated neon lighting. The robot is driveable so you can take the party on the road! It was created in my garage using standard hand/power tools and readily available parts and materials.

BaR2D2's creator, Jamie Price, sent us a link that includes all the construction details, as well as a few photos of the droid with C3PO, R2, Vader, and some Stormtroopers at the Dragon*con convention.

Build A Mobile Bar - BaR2D2

January 1, 2009

Minty soldering jig

Bob Hickman, Minty Amp maker, sent us a howto on making a jig for small form factor soldering projects.

I often have to solder up a bunch of PCBs that are the same size, but have a bunch of fiddly components on them.

To save time and frustration, I decided to re-purpose a used chewing gum tin to make a jig so I could solder multiple boards at once and keep my components from moving about.

His hack allows you to place all of the components and then solder them all at once, which is pretty handy even if you're not soldering a bunch of boards at the same time. The trick is to cram a bunch of flame retardant foam inside and close the top cover, sandwiching the components onto the PCB. You can then move things around as you please and your hands are free to work the solder and iron.

Simple Soldering Jig

December 28, 2008

Controlling Sony camcorders with the Arduino

The Local Application Control Bus System (LANC) is the protocol used by Sony camcorders (and some other brands as well) that allows external accessories to control the camera remotely. On most cameras, you'll find a LANC port next to your camera's other IO jacks—it's usually a 2.5mm headphone-style jack, or a 5 pin mini-DIN.

If you're an Arduino fan, you can easily create your own custom devices that can interact with your camcorder using the LANC protocol, allowing you to control zoom and record functions from your own programs. Goose wrote about his own project and example Arduino source:

I found source code to do LANC control with the Arduino board. It was written quite well - it worked the first time out. I made a few changes though, specifically changing it from being controlled by a serial port to being controlled by a potentiometer. I plan to build my own zoom controller with it, using an Arduino Mini.

The original code comes from Brady Marks. Make sure to check out the README and other documentation inside the source zip file. Along with the Arduino source, there's a bunch of LANC protocol documentation as well as some collected emails and mailing list discussion on the topic.

Zoomduino - Arduino Zoom Controller
SONY LANC Protocol Details
Brady Marks' Arduino LANC Source

December 26, 2008

Das DereLicht - ham radio transmitter from a CFL bulb

They usually work so well, it's easy to forget about all the electronics crammed inside a compact fluorescent light bulb. MAKE reader Ollie AJ1O sent us a link to ham Michael J. Rainey's (AA1TJ) "Das DereLicht" radio, a transmitter made almost completely from the parts of a defective CFL bulb.

This electronic puzzle was a result of my changing a defective compact fluorescent lamp (CFL) in my kitchen. For some reason, I began to wonder if it would be possible to build a QRP CW transmitter using the electronic components salvaged from this derelict lamp.

Indeed, I'm pleased to report that a perfectly serviceable transmitter may be constructed! The only additional components required were the quartz crystal, and four of the five components needed for the output lowpass filter. The resulting transmitter produces up to 1.5 watts on 80m.

For all the hams out there: what's the coolest radio hack you've created or heard of? Send us a shout in the comments.

Das DereLicht - Ham Radio From A CFL Bulb

December 23, 2008

Gravitron - ping pong ball LED toy

Marcus wrote in to tell us about his latest ping pong ball electronics project, the Gravitron. In half of a ping pong ball, he's crammed 12 LEDs, an accelerometer, and an ATmega168 for a brain. If you pick it up and tilt it, it will light the highest LED. It's sort of poetic.

If you're as impressed as I am with his efficiency of space, check out Marcus' other ping pong ball experiments on his blog.

Gravitron - Playing around with gravity

December 13, 2008

FPGA hacks - Cornell ECE5760 final projects

We've previously covered the student projects that come out of Cornell's microcontroller design courses, and I'm always excited to see what's released each semester. Bruce Land wrote in today with an update on the Fall 2008 FPGA projects:

During the last 5 weeks of the fall semester in ECE576, Advanced Microcontroller Design, students at Cornell University are given the responsibility of using an Altera/Terasic DE2 FPGA development board to build an interesting system-on-chip project. This year's projects include an graphical L-system generator, a brute-force DES keyspace searcher, a polygon render pipeline, and speech recognition engine. The projects are typically combinations of hardware specified in Verilog and C software running on an embedded controller, although some are pure Verilog generated hardware. The projects range from tools to games. The parallel nature of the FPGA encourages graphics and audio applications, but infrastructure applications such as hardware UDP are encouraged.

Show above is a two player FPGA version of Tetris. If you've been interested in developing software for FPGA devices, the Altera development boards will set you back about $600, but the projects from this course all all open source and a great place to look for inspiration.

ECE 5760 - Advanced Microcontroller Design and system-on-chip
Advanced Microcontrollers Final Projects

Previously:
Cornell University's student microcontroller projects - Spring08
Microcontroller design final projects from Cornell University
ECE576 Final projects

December 3, 2008

Hacker Gift Guide: Gift ideas for your favorite geeks

When I look for gifts for a lot of my friends, the most important thing on my mind is finding things that are hackable. Is the gift modifiable, open source, and fuel for future projects? Does it teach you something? These are essential qualities in a hacker gift.

In this guide, you'll find a collection of gadgets, books, and gear that have carefully been selected for their fundamental hackability and technical awesomeness.

The list starts off with an obvious gift candidate, the open source/open hardware Arduino.

The Arduino has quickly become the platform of choice for hardware hacks and physical computing projects requiring a microprocessor. The devices are cheap, fun to program, and there's a healthy community of Arduino hackers publishing both software libraries and hardware add-ons. For many applications, you'll want to check out the Arduino Duemilanove, which is compatible with snap on "shield" daughterboards like the robot friendly MotorShield or the XPortShield ethernet adapter. A lot of projects can also benefit from the ultra small footprint and breadboard compatible Boarduino, which you can assemble yourself for only $17.50.

Price: $17.50 - $34.99

A great gift idea for someone who's new to Arduino is the Arduino Starter Kit. It's currently backordered, but if you order quickly you can still get one in time for Christmas. It includes an Arduino Duemilanove, a huge pile of electronic goodies, and the book Making Things Talk by Tom Igoe.

Price: $89.99

Read full story

November 25, 2008

Fuzebox - open source 8-bit game console

Ladyada released a new guide today which shows you how to make the Fusebox, an open source 8-bit console. It's based on the Uzebox project and provides you a fun Nintendo-like platform on which you can develop and play open source, homebrew games. Below is a video of the original Uzebox running the "AVR Megatris" Tertris clone:

The Fuzebox is a fully open-source, DIY 8-bit game console. It is designed specifically for people who know a little bit of programming to expand into designing and creating their own video games and demos. A full-featured core runs in the background and does all the video and audio processing so that your code stays clean and easy to understand.

You can build your own from scratch with the supplied documentation, or you can buy a kit from the Adafruit store and solder it together. Looks like a pretty fun project.

Fuzebox

November 22, 2008

Hacking the Wiimote IR camera

You can connect to the Wii remote over bluetooth or use an Arduino to send peripheral data to the Wiimote, but what if you want to interface directly with the Wiimote's IR camera? The sensor is particularly good at tracking coordinates for 1 to 4 points—it could be a simple way to add sophisticated tracking capabilities to your own project.

David Cranor writes,

There is a great site about hacking the wiimote IR camera to interface it with a computer - but it's all in Japanese! Perhaps you could post these links and see if anybody could translate it?

This page details how to desolder the camera itself and build a standalone circuit for it so that it can be connected to an I2C bus, and subsequently a computer (i think, anyway - the schematics are in English, and there's a video).

And this page talks about how to connect the camera to an Arduino via some of I2C shield that he's built.

I'd really like to have access to this information for my projects, so if somebody would be able to translate these pages, that would be awesome!

A quick run through Google's Japanese to English translator yielded a reasonably understandable result:

Wii IR sensor connection details
Connecting the Wii IR sensor to Arduino

The second link contains a wealth of information on talking to the IR sensor over I2C, including some details on adjusting sensitivity parameters. The translation is a little rough, but combined with some of the sample code, I think I have the gist of it:

To initialize the IR camera, you have two options: 1) a simple, default initialization or 2) an initialization that allows you to specify 4 configuration parameters that affect the sensitivity of the device.

Simple Initialization:
Just write the following byte sequences, with a small delay between writes (assumes a successful ACK). The first byte on each line is the register you are writing to.
0x30 0x01
0x30 0x08
0x06 0x90
0x08 0xC0
0x1A 0x40
0x33 0x33

Initialization with sensitivity setting:
The author defined 5 sensitivity levels, and there are four parameters (p0, p1, p2, p3) that are adjusted for each level. Here are the settings:

Level 1: p0 = 0x72, p1 = 0x20, p2 = 0x1F, p3 = 0x03
Level 2: p0 = 0xC8, p1 = 0x36, p2 = 0x35, p3 = 0x03
Level 3: p0 = 0xAA, p1 = 0x64, p2 = 0x63, p3 = 0x03
Level 4: p0 = 0x96, p1 = 0xB4, p2 = 0xB3, p3 = 0x04
Level 5: p0 = 0x96, p1 = 0xFE, p2 = 0xFE, p3 = 0x05

Quoting the Wiimote Wiki IR sensor page, these parameters correspond to:
p0: MAXSIZE: Maximum blob size. Wii uses values from 0x62 to 0xc8
p1: GAIN: Sensor Gain. Smaller values = higher gain
p2: GAINLIMIT: Sensor Gain Limit. Must be less than GAIN for camera to function. No other effect?
p3: MINSIZE: Minimum blob size. Wii uses values from 3 to 5

Either pick your own custom settings for the parameters, or choose them from one of the 5 levels above, then send the following data to the device:

0x30, 0x01
0x00, 0x02, 0x00, 0x00, 0x71, 0x01, 0x00, p0
0x07, 0x00, p1
0x1A, p2, p3
0x33, 0x03
0x30, 0x08

The author also links to the following source, which serves as a helloworld for reading sensor data directly from the IR camera:

Wii Remote IR sensor test for Arduino
Wii Remote IR sensor test for ATMEGA168

Finally, since the IR sensor is a 3.3v device, you'll want to do a little voltage conversion before interfacing it directly with a 5v device like your typical Arduino (Arduino Pro users don't have to do a thing). Sparkfun has a guide for using 3.3v electronics with 5v microcontrollers, which should be all you need. It makes me wonder if anyone sells a pre-built 3.3v shield.

Hopefully this is all you'll need to get things working. Make sure to send us a tip if you make something cool using the Wii IR sensor.

Previously:
HOWTO: Make a Wiimote peripheral
Hook your Wii nunchuck up to an Arduino

November 21, 2008

Bus Pirate - universal serial interface

Ian Lesnet sent in a link to his Bus Pirate project, a universal bus adapter that lets you interface with most standard integrated circuit serial protocols at different voltages - all from you PC's serial port. The idea is that you can debug, test, and prototype ideas a lot faster if you don't have to breadboard an interface circuit every time you work with a new chip.

the bus pirate is a serial terminal bridge to multiple ic interface protocols. we type commands into a serial terminal on the computer. the commands go to the bus pirate through the pc serial port. the bus pirate talks to a microchip in the proper protocol, and returns the results to the pc.

all pins output 3.3volts, but are 5volt tolerant. on-board 3.3volt and 5volt power supplies are available to power the connected chip. software configurable i2c pull-up resistors complete the package.

the serial terminal interface works with any system: pc, mac, linux, palm pilots, wince devices, etc; no crapware required. we considered a usb device, but usb isn't compatible with the huge number of hand-held devices that have a serial port. we also wanted a 3.3volt device with 5volt tolerant inputs, but most popular through-hole usb microcontollers were 5volt parts (e.g. the pic18fx550).

The device supports i2c, spi, uart/serial, and raw 2-wire and 3-wire. It looks like a pretty handy little tool, and Ian has included all the information you need to build one of your own.

The Bus Pirate

November 19, 2008

Wii Theremin

Ken Moore, a user experience designer at Google, created a very convincing Theremin simulator using a Wiimote and a Roland JV-1080 synth.

I've seen a few Theremin simulators that use accelerometer data, in both Wiimote and iPhone form, but this is the first I've seen that does a good job of recreating an authentic Theremin experience in all its 50s sci-fi awesomeness. Using some IR gloves and the Wiimote's CCD, one hand's horizontal movement controls pitch and the other hand's vertical movement controls volume.

At just $35, the Wiimote is an AMAZING piece of technology. It has an infrared camera in it which tracks the position up to 4 infrared light sources. So I bought a pair of leather gloves, wired up a couple infrared LEDs to 1.5 volt batteries, and poked an LED through the tip of the index finger of each glove.

Then, I connected my Wiimote to my computer (the Wiimote also supports Bluetooth connections): building on top of Brian Peek's Wiimote hacking software library, I wrote a program which detects the two infrared gloves and converts the vertical position of the left hand to volume, and converts the horizontal position of the right hand to pitch. That information is then sent via MIDI to the synthesizer which creates the actual sound.

One of the more interesting possibilities with this setup is that by adjusting the synthesizer, you can use a Theremin-like interface to control a huge number of effects, not just the standard sci-fi sine wave. I wonder if Léon Theremin would approve.

Wii Theremin

November 15, 2008

Myvu Crystal as a wearable head mounted display

Ralf Ackermann sent us a tip on using the Myvu Crystal headset in conjunction with a wearable computer. The Myvu glasses were designed to block out the rest of the world for private iPod video watching, but its VGA resolution and device compatibility makes it pretty suitable for tearing apart.

The consumer myvu crystal HMD (sold as a nice though still somewhat "socially unacceptable" 2 eyepiece video output device for the ipod and other devices generating a PAL/NTSC signal can be modified into a much smaller 1 eyepiece version. This one works very well with a multitude of devices like a Parallax propeller, a Nokia N95 via TV out or a Archos PMA 430. It is thus well suited as the core of "another wearable computer".
For this purpose it might also be combined with the iphone / ipod touch
Xbee IO extension described earlier this week.

Ralf's project is still a work in progress, but it's a reminder that most of the hardware required for a wearable is now commonly available. Considering most of us already carry a sufficient computer (iPhone, N95, G1, etc.) around with us all the time anyway, it's only a matter of time before a HMD design is made cool enough to dodge the social stigma.

Myvu Crystal HMD Modification (Flickr Photo Set)

November 9, 2008

SlugPower - Linux controlled power switch

Phil Endecott has done a bit of hacking with the Linksys NSLU2 "Slug", the low-power network storage device which runs Linux under the hood. His SlugPower project is a switched outlet that can be controlled from the Slug. This enables his print server to power up the printer when it needs to be printing, and automatically cut power to the device when it's not in use.

This page describes the hardware and software design of a printer power switch controlled over USB from my Linksys NSLU2, aka Slug. The unit can, however, be controlled from any Linux box, and can switch anything, not just printers.
My NSLU2 acts mostly as a file and print server. I can go for weeks without printing anything, so I want to keep the printer switched off when I'm not using it (it takes about 4W while idle, which must be more than 99% of its total energy consumption). But it's upstairs, and I don't want to have to go up and down stairs once to switch it on and again to collect my printing. So I decided to get a power switch.

Remote power switches are pretty common in server rooms, but they are costly. This is a pretty affordable way to control the power to any device from anywhere in the world.

SlugPower - A Slug-Controlled Power Switch
Phil Endecott's Slug Projects
NSLU2-Linux

November 2, 2008

Telescope control with stepper motors

If you want to take a stab at amateur astrophotography, or have a telescope with "goto" or auto tracking capability, you either need to make a substantial investment in hardware and software, or you can built your own computer controlled mounts and use a variety of open source telescope guidance software packages. I caught the following discussion on the Twin Cities Robotics Group's mailing list today. Robot hacker Bruce Shapiro posed this question to the list:

I've started another one of my "bits to bots" classes-- this time out here at the local art center, and with adults. One of the students is very keen on the idea of stepperizing his telescope, and already has put in a lot of effort rolling his own stepper drives. I seem to recall that this is a common goal, and that there is both some decent free/shareware out there that will control your motorized scope, as well as plans for the retrofit. But a quick search just turned up a bunch of individuals' pages that didn't have the pizzazz I think I remember once seeing. Basically, I'd like to save him from reinventing this wheel. I suspect some of you may be able to point us in the right direction?

The quick response from list member Alan Kilian was to check out Mel Bartels' BBAstroDesigns site. It contains a wealth of information for hobbyists looking to build a DIY computer operated telescope. A lot of the information is for Dobsonian mounts, and you'll find howtos for adapting your telescope, building the stepper control electronics, and software for controlling the rig from a PC. Depending on what you choose to do, you can completely automate your scope for somewhere between $100 and $500.

BBAstroDesigns - Computer Operated Telescopes
Mel Bartels' Telescopes and Telescope Making
Twin Cities Robotics Group

Illustrated Guide to Astronomical Wonders: Get it now at the Maker Shed

October 29, 2008

Arduino control with Flash AS3

You can communicate from Flash to an Arduino device by using a proxy. The proxy runs on a machine which is connected directly to the Arduino with a serial connection. Your AS3 code talks to the proxy over a TCP socket, and the proxy talks to the Arduino over the serial connection.

This whole setup is made pretty simple by Erik Sjodin's as3Glue library:

as3Glue is an ActionScript 3 library that enables communication between Flash/Flex/AIR applications and Arduino boards. It can together with one or several Arduino boards be used to monitor sensors (such as rotary encoders and motion detectors), control actuators (such as LEDs and motors) and interface other electronics (such as RFID readers) from Flash, Flex and AIR applications.
The library includes Arduino sketches and ActionScript 3 code examples as well as custom version of the Standard Firmata Arduino firmware and a serial proxy.

The AS3 portion of the library is released under the MIT license, and provides methods for setting pin modes and writing digital and analog data to pin output. It also provides event callbacks for receiving digital and analog data back from the device. The only wonky thing is that the proxy doesn't appear to be released in source form (as far as I can tell), and it's only provided as binaries for Windows and Mac users. On the bright side, it's pretty easy to digest what's happening from the Arduino.as file and the Standard Firmata protocol, so it wouldn't be a huge ordeal to cobble together your own proxy if you know a little C or PERL.

as3Glue - Arduino control from Flash, Flex and AIR
SimpleIO.as - a decent AS3 Arduino example
Firmata - host machine to microcontroller communication protocol