[Moris_zen] built a device to accurately measure the capacity of batteries. He needed to have an accurate measurement for the batteries he uses in a RC airplane. Knowing the discharge time allows him to fly the friendly skies while avoiding crashes from lost communications.
He based the tester around the Arduino platform. Instead of using a pre-built Arduino board he referenced the open source schematics and built the device from components to fit his needs. His solution automatically detects the battery type (Lithium-Ion, Nickel Metal Hydride, etc) based on voltage when the battery is added to the circuit. It then uses a 2.2 Ohm resistor and ADC measurements to take the battery through a discharge cycle. A character display shows status information with the ability to track discharge information using a computer to graph the data.
Apart from flashing an LED this was his first Arduino project. It’s a great use of the platform and much more automatic than other solutions we’ve covered.
They’ve come a long way since we last looked in on the progress. The hardware used is pretty much the same: a set of sunglasses sans lenses with the CCD from a Sony PlayStation 3 Eye mounted in front of one eye. IR LEDs surround the CCD and point at the eye to increase the contrast between pupil and the rest of the eye. The major improvement comes with the software. Eye tracking appears to be extremely precise and they’ve written a custom drawing program to take advantage of their interface. Check in on their developer page for source code and a video walk-through of the software.
After the break you can see video of [Tempt1] using the system to create some tags. We’re thankful for the success this project has seen as this guy can do a lot better with his eye than we can with our hands.
posted Nov 11th 2009 7:47am by Caleb Kraft
filed under: news
[Nico]‘s microblog has been a regular source of inspiration since we were introduced to it last year. Aside from posting various technical thoughts and reviews, [Nico] won our hearts over by going through the trouble to strip chips and photograph them for our pleasure. Browse through his archive and download what you want, because he’s shutting down. The posts have waned, due to his final year of school taking all of his time and graduation is coming soon. [Nico] will be looking for a job soon, so check out his resume (pdf) if you’re looking for an engineer.
Here’s one that brings back that giddy feeling we got when the original episodes of thebroken were posted all those years ago. The lunatics over at Waterloo Labs have altered a beat-up Oldsmobile for remote control via laptop, iPhone, and…. wait for it… Power Wheels.
Brake and gas pedals are actuated using a wrench connected to a motor bolted to the floorboards of the car. The steering wheel has been replaced with a gear and connected to a motor using a motorcycle chain. Much like the van we saw last month, an iPhone app has been written to wirelessly control the car of doom. This leads to some car surfing and ghost riding the whip in the video after the break.
To our delight, they’ve also implement the most unorthodox automotive interface yet, Power Wheels. A chain has been added to measure the orientation of the toy steering wheel, and an optical encoder is used to measure the speed of the tiny electric vehicle. It looks like it doesn’t do the best job of translating to a full size vehicle, but it maxes out their style points.
Slow day at the office? Here’s a trick that’ll make your coworkers smile. Dangerously Fun has a guide to build a homopolar motor from a battery, copper wire, and magnet. A homopolor motor doesn’t rely on electromagnets in an armature changing their polarity to force a rotation movement compared to stationary magnets. Instead, they use an electrical current’s orientation to a magnetic field to provide a repulsive or rotational force. In this implementation, the current moves through a loops of copper wire from one pole of a battery to the other. A rare-earth magnet on one pole of the battery provides the magnetic field.
After the break we’ve embedded video of this simple example as well as a few more complex homopolar examples such as a five speed version. The motor in action certainly brings a smile to our faces and places this firmly in the useless machines family of hacks.
[Kizo] repurposed a flatbed scanner to use as an exposure box for making printed circuit boards. Exposure time is controlled by an AVR ATtiny2313 microcontroller. The device is connected to a separate display board to control four 7-segment displays using one shift register for each. Time is set in ten second increments and once started, switches on the lights with a relay. Once the right exposure time has been reached, the lights are switched off and a piezo speaker is buzzed. There’s no mention of they type of bulbs he’s using but they look like compact fluorescent with tin foil beneath as a reflector.
120 LEDs and NerdKit, check. Python and appropriate Google Voice module, check. Blend on high for 2 minutes, bake for an hour at 400 degrees Fahrenheit. Your soufflé is done, whoops, we mean your voice controlled LED sign is done. Leave a voicemail on Davis’ Google Voice account that starts with “message” and it will be displayed for all to read within a matter of minutes. We think: make it bigger and add a security code before you can leave a message, and you’ve got the perfect recipe for some over sized message fun.
[Jack], [Cory], and [Maciej] are playing Pac-Man with Roombas on a lab floor. The Roombas are outfitted with ALIX3d2 single board computers running Gentoo and a software suite developed for UAVs at the University of Colorado at Boulder’s Research and Engineering Center for Unmanned Vehicles. The hardware and software sections are quite in-depth and make for a good read.
