Matrixsynth pointed out a couple incredibly small optical theremins that look like they’d make for a great afternoon project. [AlexArt] first built the simple circuit on a piece of protoboard (Google translated). Knowing he could go smaller, he then built it freeform with a buzzer instead of a full size speaker. The design is based around the common 555 chip and photoresistor. Here’s a simple circuit you can use to lay out your own. The optical theremin should not be confused with the traditional RF theremin since the name comes from the similar sound, not similar construction.
Year: 2008
Coin Slot Detector
Wow, how quickly the wearable electronics world has slid into the gutter. They’re now resigned to watching our nations finest natural resource, the butt crack. This project by [semiotech] uses a LilyPad Arduino to monitor the exposure of the wearer’s coin slot. It detects the presence of light with a photoresistor and alerts the user with the vibrations of a pager motor. This breakthrough in coin slot technology will prevent dryness and certainly reduce our exposure to domestic terrorism. We see plenty of room for future development; the Arduino is already capable of logging exactly how often your coin slot is exposed. Even if you feel this is more protection than your coin slot needs, we recommend Neutrogena’s Coin Slot Cream for general upkeep.
LED Life And Charlieplexing
Yesterday, we featured [Andrew]’s orientation aware camera. We want to highlight another one of his projects: LED Life. It’s a 6×5 LED matrix playing Conway’s Game of Life. He used the low power MSP430 like our e-paper clock. The best part of the writeup is his explanation of how Charlieplexing works. Microcontroller GPIO pins generally have three possible states: output high, output low, and input. This combined with the directional nature LEDs and some creative wiring means you can run a large matrix of individually addressable LEDs with just a few IO pins. Instead of just flipping the IO pins on and off you change their assigned state. Have a look at [Andrew]’s site for some great illustrations of how the system works. A video of his LED Life board is embedded below. Continue reading “LED Life And Charlieplexing”
Vertical Axis Wind Turbine Update
[Faroun] sent in his updated vertical wind turbine. After running his previous one for a while, he felt that the motor he was using was inadequate, it required too high of RPM to produce what he wanted. He didn’t want to gear it up, fearing that the light construction couldn’t sustain rotation.
He built a new version that has the same surface area of fins, but much higher RPM. The new one, dubbed V8 is made mainly from PVC and an Amatek DC motor. His goal was to produce 100 watts at 35km/h. He doesn’t really state whether or not he achieved it though.
Interactive Touch Capable Mirror
[vimeo http://vimeo.com/1867956%5D
[Alpay Kasal] of Lit Studios and [Sam Ewen] created this patent-pending interactive mirror after being inspired by dielectric glass mirrors with built-in LCD panels, and wanting to add a human touch. The end results look like a lot of fun. You can draw on the mirror and play games. According to [Kasal], mouse emulation is essential. The installation features proximity sensors and gesturing. Any game can be set up on it, which makes the possibilities endless… except these are the same people that built LaserGames so expect no further documentation about how it works.
[via NOTCOT.ORG]
Quick Cheap Cassette Adapter
[Dane] sent us this super quick tape adapter project. Yes, we know we can go buy one of these for pretty cheap and it will probably sound much better, but really, wouldn’t it be cool to make one? Using a headphone adapter, a couple resisters, some wire, and an old cassette tape, [Dane] shows us how easy it is to build one of our own. You are basically pushing the signal from the headphones through a coil that is up against the tape read head. This is a perfect project to teach beginners about magnetic fields.
[Dane] has sent in some stuff before. You may recall his PWM adio generation with an AVR post several months ago.
Open Source Hardware Inspires Innovation
Technology Review turns the spotlight on the open source hardware movement. Open source hardware is hardly a new concept, but lately it’s been getting a lot more attention, with the help of magazines like MAKE and websites like Instructables. Chumby, a company that sells a modifiable cube with a screen, embedded computer, and a Wi-Fi connection, designed their product to be easily hackable. The openness of the product caused a community heavily invested in the product’s development to be created. The growth of such communities has also sparked interest from corporations such as Nokia, which is collaborating with MIT on open source video decoders. They recognized that opening up would cause development time to be reduced and provide greater flexibility, allowing them to allocate resources to other areas, including marketing and brand development. [Jamey Hicks], director of the Nokia Research Center in Cambridge, believes that the open source movement can even complement closed designs, as long as it’s handled appropriately. With greater access to sophisticated software tools and resources, the barriers to entry keep falling away, and it’s much easier for the world to discover the joys of tinkering and hacking.
[photo: Andreas Pizsa]
