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Archive: Electronics

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July 8, 2008

3D Studio Max motion capture with a Wii Nunchuck

By passing Nunchuck data to a PC via an Arduino, Melka figured out a way to convert the accelerometer output into a MIDI stream that can be read directly by 3D Studio Max's motion capture engine:

Here's my setup under windows :
Arduino using a WiiChuck adapter from todbot (thanks kurt ^^) and the WiiChuck library from Tim Hirzel
Data sent to Processing via serial connection and translated to MIDI CC messages using the proMIDI library by Christian Riekoff
MIDI output from processing sent to midiYoke
midiYoke sends this data to Ableton Live
Ableton re-sends the CC messages to midiYoke
Using Float Motion Capture controllers on 3D Studio Max to rotate the objects according to the pitch and roll of the wiichuck

It's a little complicated, but from the looks of the video the payoff is worth it. You could adapt this to use data from a number of accelerometers, or turn other measurement data into a MIDI stream that can be used by any application, 3DS or otherwise.

Arduino to 3D Studio Max [via MAKE]

June 27, 2008

Arduino VGA demo

Sebastian Tomczak has been playing around with controlling VGA output from an Arduino. Using Max/MSP to process audio and send data to the Arduino and a standard VGA output to send sync data to the monitor, he's been able to put together some cool video effects.

In these examples, i am simply using three pins to control the RGB lines. However, the Arduino is not generating horizontal or vertical sync - this is generated by a computer.

You can grab the Max patch and Arduino code from Sebastian's post. I dig the effect - it reminds me of the cool C4 demos kids used to make.

Hacking VGA lines with Arduino

June 26, 2008

Flight instruments for an RC plane

There are products available that will overlay flight data into a flight camera's video stream, but here's a clever and simple hack to do it on the cheap(er). To provide in-video flight data for a first person view aircraft, just build a mini flight instrument panel and position it in front of the camera.

One of the main problem with FPV is that you can get lost very, very easily. We are not really used to know our environment from a bird's eye view!
Here is one solution to find your way back home:
The device below includes a GPS receiver and a microcontroller (it's inside the blue heatshrink sleeve) grabs interesting data like latitude, longitude, altitude and speed from the NMEA sentences, calculates bearing to destination (the pilot) and displays relevant data to the "instruments" (micro servos with a needle!)

On the left: speed, in km/h
In the middle: bearing to destination - if the needle is vertical, you're on the way back home!
On the right: altitude, in meters (divided by 10)

This is something you could easily build yourself and you'd be able to add any features you wish. I'm thinking a data logging feature would be cool. That, or a geo-targeted pingpong ball deployer.

Aircraft Panel For First Person View

June 25, 2008

Image Fulgurator - subverting other people's photos

Berlin hacker Julius von Bismarck invented and patented the Image Fulgurator, a device so awesome that it can remotely insert images into other people's photos.

You aim the device at the same subject that another person is photographing, and when they snap a photo the resulting image will be manipulated with a separate, overlayed photo. The person taking the photo will have no idea anything happened until they examine their photo.

The result is pure magic. Here's a clip of the first public "image fulguration".

The device uses a standard 35mm camera body and lens as a projector. Instead of undeveloped film, the camera is loaded with exposed, developed slide film. A flash is built into the back of the camera, sending light backwards through the body, past the the slide and out the telephoto lens. A light sensor is used to trigger the flash when another camera's flash goes off. Thus, when someone else takes a photo, the Fulgurator zaps its slide's image onto the object for a few milliseconds.

In you want to make something like this, you can use some of the techniques that folks typically use to photograph lightning. Below is a link to a simple Arduino project that will give your SLR a light activated shutter release.

While you're at it, take a crack at making your own Fulgurator with a bit more stealth factor. I'm pretty sure I'd get tazed walking around downtown waving this thing around.

It'd almost be worth it.

Image Fulgurator by Julius von Bismarck [via The Future is Awesome]
Lightning Trigger for a Camera

June 16, 2008

Controlling stepper motors

I've become so familiar with using standard DC and servo motors for my electronics projects that I've been neglecting a resource that I seem to have an unlimited supply of. There is a mountain of old floppy drives growing in the basement chock full of stepper motors waiting to do a robot's bidding.

The benefit to using stepper motors, besides the abundant availability in all sorts of junk electronics from printers to floppy drives, is that they can be controlled in precise increments. The only downside is that they are a little more complicated to use. For the electronics gurus in the room, controlling a stepper motor is probably old hat. For the rest of us, here are some handy links that'll help you resurrect some old peripheral guts.

Control of Stepping Motors by Douglas Jones
Use disk drive steppers from a parallel port
Tom Igoe's Stepper Motor Control - circuit variations and microcontroller (including Arduino) source
Arduino/Wiring Stepper Library

To use a stepper motor with the Arduino, check out Tom Igoe's documentation (third link). The circuit is straightforward— you'll only need the stepper, your Arduino, and a Darlington array (for unipolar motors). There's an additional tutorial that ties this all together here: Unipolar Stepper Motor Arduino Tutorial.

Go forth, make some cool stuff, and send us a link to your creations.

June 11, 2008

YBox2 - a networked set-top box

The original YBox was a nifty little electronic gewgaw that made it easy to make a network appliance that displayed itself on a TV, all fit into an Altoids tin. The kits have been sold out for quite a while, but I'm excited to hear that it's been given a second life in the YBox2 platform.

Robert Quattlebaum undertook the task of creating the new version and teamed up with ladyada to help bring the new kits to the hacker masses. It's built around an 80MHz 32KB Propeller chip, supports NTSC and PAL, and comes prepackaged with a bootloader that allows you to upload new firmware over ethernet instead of requiring you to use a programmer cable.

This is an open hardware project, so you can either build it from scratch or purchase a kit from the adafruit store. All you'll need to do after that is write a cool widget for it and send an email my way so I can post it here. :)

YBox2 - DIY Networked Set-top Box

June 6, 2008

Electronic embroidery

I'm told that one of the most popular projects at the CRAFT table at Maker Faire is our friend Becky Stern's electronic embroidery. If you're into crafting, all it takes is a little conductive thread and you can make your own fabric gadgets.

Becky posted an introduction to electronic embroidery on the CRAFT blog today and I think I just learned how to backstitch. Her introduction shows how to wire up a couple of LEDs and a switch, but there are a lot of directions to take this. Of particular interest is the LilyPad, a tiny sewable Arduino board that's about the size of a half dollar. There are also various sensors designed around this platform, including sew-friendly accelerometers. There must be a good running jacket idea in there somewhere.

Electronic Embroidery - CRAFT Video Podcast
Conductive Thread and LilyPad Components at SparkFun

June 1, 2008

AVR tri-color LED controller

A little while ago we posted about a fun LED scroller project made by Hackszine pal Kalanda. He wrote in today with an update about his latest howto project, a multi-color animated LED controller based on the AVR platform.

The new project based in AVR microcontrollers Its an "Habitat Mirror Hack" with RGB Leds (superflux). Its the Peggy Muppets Mirror.
I replace the regular bulbs that it has, with superflux RGB leds and i make a controller based on ATMEGA8 for control 16 rgb leds with 3 bits of color depth (8 colors). In my post you can download scheme, pcb and source code.

It looks like a fun project, and you could adapt it for other uses pretty easily. His site is in Spanish, and though I'd normally like to a Google Translate version, unfortunately Translate isn't converting the entire post, only the first paragraph. To get the full details, you'll have to cut and paste the text into Translate manually.

Thanks, Kalanda!

Kalanda's RGB Mirror: an AVR tri-color LED controller

May 29, 2008

Wii Balance Board hacks

A few days ago, this video appeared with Matthieu Deru and Simon Bergweiler showing off a hack that allows them to surf Google Earth using a Wii. Unfortunately, there weren't too many details about how it was accomplished and I couldn't track down any source for the C# application that talks to the bluetooth device.

What I did find was this other clip from almost a month ago (?!?) in which Daniel Schneider demonstrates using the Wii Balance Board to navigate the web in Firefox.

That's right. You can actually surf the web:

He's using the latest version of GlovePIE (v0.3) to accomplish this. As far as I can tell, it's still very alpha, and the WiiLi wiki claims it's buggy, but it does appear to work. Daniel has some pointers to how he's configured things, including the Greasemonkey script that allows you to surf without clicking.

For more information on coding GlovePIE scripts that use the Balance Board, peek at the documentation.rtf file that's packaged with the GlovePIE download. There's information around page 70 that describes how the board functions and how to pull the 4 sensor values from each of its feet.

Using GlovePIE and Firefox with the Nintendo Wii Balance Board
GlovePIE

May 15, 2008

Gmail notification cube

Jamie Matthews created a nifty notification cube that glows when his Gmail inbox has a message.

I was given a lovely glowing cube by the generous people at Linden Labs as a freebie at a job fair yesterday, and I decided that it was far too attractive to simply sit there on a shelf, pulsating forlornly until its batteries went flat. How about making it useful, while maintaining its visual appeal?

A simple python script runs on his computer, periodically screen-scraping his Gmail inbox looking for new mail. It then outputs a message to the serial port, indicating the mailbox status. On the other end of the serial connection is a Boarduino, which receives the message and toggles power to the cube.

You could start with his code and get a jump-start on doing something similar. It looks like this could inspire a fun project or two on a lazy afternoon.

How to make a Physical Gmail Notifier

May 7, 2008

Radio controlled lawn mower

It's finally starting to warm up where I live on the 45th parallel, which means it's just about lawn mowing season. It's not a chore I typically enjoy, but this RC lawn mower designed and documented by Terry Creer looks like it might be a kick.

Here's the best feature, from the project website:

THE METHODS OF CONTROLLING AN UNMANNED VEHICLE DETAILED BELOW ARE POTENTIALLY LETHAL. YOU CAN KILL SOMEONE, AN ANIMAL OR A ROSE GARDEN IF YOU ARE NOT CAREFUL.

Sign me up! That also goes for anything else involving combustion, electronics and spinning blades of lopping frenzy. Here's a video on YouTube. I'm not sure you're going to get those nice striped patterns without a lot of practice, but I'm also not sure that it really matters.

If you're keen on making your own, it's basically an electric wheelchair with the joystick control replaced with the receiver circuitry and the lawn mover hardware bolted to the frame. The site has all the circuit and mechanical details. You should be able to scrounge for parts and put one together for $450 or so - less if you don't count the mower you've already got that you'd rather be driving from the porch.

DIY Radio Controlled Lawn Mower

May 5, 2008

Cornell University's student microcontroller projects - Spring08

Another semester's worth of cool microcontroller projects has come to a close at Cornell University and Bruce Land sent us the results for the Spring 2008 ECE 4760 course:

Students in ECE 4760 at Cornell University were given the responsibility of choosing, designing and building a project using Atmel Mega32 microcontrollers. Over 30 projects this year include a trumpet MIDI contoller, a motorized guitar tuner, a eyeblink/head-motion computer controller, Biometric Authentication system, and a rocket inertial guidance system.

There are a number of projects worth commenting on, but I really thought the rocket guidance system that one of the teams created was a particularly smart idea. It's a bit of a misnomer - it's not the rocket that's guided during flight, but the post-flight payload. The microcontroller, an accelerometer and two stepper motors are employed to steer a simplified parafoil-style parachute on the descent, ideally delivering the payload to a specified location, such as the launch point.

It sounds like this particular project had some launch-day engine malfunctions, but the idea is great. Something like this could someday be used to help direct food payloads and other cargo drops to a specific, controlled destination.

I think this marks 10 years worth of great work that's been documented online for this course. As always, these projects are incredibly well documented, both on the hardware and software side.

Cornell University ECE 4760 Student Microcontroller Projects
Rocket Inertial Navigation System

April 27, 2008

DIY 7x5 LED scroller

Kalanda sent in this 7x5 dot matrix LED scroller based on the Attiny2313 AVR microcontroller.

It looks like a fun little project, but the part I really dug was the way the animation is programmed. The author created a simple LED Composer HTML/Javascript page that lets you visually construct the layout of the animation, its speed, and the animation style (scrolling or frame by frame animation). You simply click on the virtual LEDs, make it look the way you wish, and a textbox spits out the necessary array for you place in your program.

Here's a link to the project site, both in original form, and lovingly translated by caged typing monkeys at Google:
7x5 LED scroller based on micro Attiny2313, English translation

April 25, 2008

Simple bike computer from scratch

Here's an excellent tutorial that'll show you how to build and program a bike computer using a PIC and a homemade PCB, all from scratch using free tools:

The bulk of the article that follows is to try and take the mystique out of the many steps involved in going from an idea to a finished product.
You won't of course be ready to go into full scale industrial production, but you will now be aware of the things that have to be done, and know how to do them.
We will look at and master:

Hardware steps

Making a PCB from scratch
How to use the FREE tools
Software steps

Very basic Pic source coding

Using MPASM
Getting the HEX into the PIC

With the nice months ahead, you might as well be out riding. Why not keep track of all those miles on a computer of your own design?

Simple Bike Computer - Learn how to program a PIC

April 24, 2008

Open GPS Tracker

Now this looks like fun:

The Open GPS Tracker is a small device which plugs into a $20 prepaid mobile phone to make a GPS tracker. The Tracker responds to text message commands, detects motion, and sends you its exact position, ready for Google Maps or your mapping software. The Tracker firmware is open source and user-customizable.

From the looks of things, the total cost to build a remote-operated GPS tracking unit is on the order of $100. The design uses a prepaid cell phone to receive commands and report its position via SMS.

I'm sure there are a number of boring nefarious application for this that will freak out a lot of folks, but just think about the more interesting possibilities. You could add this to a weather balloon or autonomous flying vehicle easily track it down if there were any flight problems. A bunch of people in any city could put these in their cars on a short time delay and automatically report traffic flow conditions. You could even roll your own "lo-jack" system that would let you find your car if it was stolen, only with this your car's location is only being reported to you instead of a monitoring station, actually increasing your privacy.

Open GPS Tracker