Virtual Machine For Microcontrollers Lets You Run Python On AVR Chips

August 31, 2011 by Mike Szczys 23 Comments

[Clifford Wolf] wrote in to let us know about a project he recently completed called EmbedVM. It’s a virtual machine for AVR microcontrollers. The package has a relatively small overhead, taking up about 3kB of program memory. The VM can execute 74,000 instructions per second, and runs asynchronously from the microcontroller. As [Clifford] demonstrates in the videos after the break, this can be handy for preloading commands to prevent slowdown during heavy VM processor loads.

The snippet in the image above is an example program written in the C-like VM code which will play some [Rick Astley] on a speaker. This code can be run from RAM, EEPROM, or even external storage like an SD card. Recently there was a supplemental compiler project that even takes Python code and compiles it into VM byte-code. What a nice abstraction tool for making inexpensive microcontroller-based designs easily programmable for those that have a bit of Python experience.

If you don’t recognize the name, [Clifford Wolf] is also the author of OpenSCAD, a tool that is quite popular with 3D printing.

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The Life And Death Of A Fantastically Brilliant Flashlight

August 31, 2011 by Mike Szczys 21 Comments

[Holzleim’s] flashlight build is quite impressive. And the rise and fall of the hardware is quite a story. He designed it as a handheld light, relying on batteries to power a multitude of high-power LEDs inside.From the collection of four 5350 mAh lithium polymer cells he was able to achieve a peak power output that surpasses 500 Watts!

Projects that make use of these powerful LED modules have heat dissipation as a major design element. With this in mind, [Holzleim] used large bars of copper as a mounting surface for each group of modules. The size and thickness of these bars made it difficult to use traditional soldering techniques to affix the bodies of the modules so he ended up using a clothes iron to ramp up the temperature high enough to reflow the solder. Once mounted, most of the LEDs were paired with optics, including that Fresnel lens at the center, to help focus the light.

To keep the batteries topped off, [Holzleim] designed his own external charger which can run off of mains or from a car’s electrical system. Unfortunately he must not have included a way to monitor the battery temperature because one of the cells failed, causing a fire that burnt out the components inside the flashlight. Luckily his wife was home at the time and got the failing device outside where it didn’t cause more damage. We’ve linked to his posts regarding the charging system, the properly functioning light burning paper with its beam intensity, and his sad announcement about the fire after the break.

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Making A Line-following Toy Into A Programmable Robot

August 31, 2011 by Mike Szczys 1 Comment

[Eric Gregori] picked up this little yellow robot as a kit build. It has a single PCB inside that has a pair of IR emitters and detectors pointed downward at the front of the robot. It is able to follow a dark line on a light surface based on how the infrared beam reflects back to the detector. But it’s a one-trick pony that [Eric] wanted to make into a programmable robot.

The kit came with a schematic, which makes the process of patching into its logic quite easy. There are two motors, each with a driver circuit made up of a pair of transistors and one flyback diode. This means the motors can only move in one direction, but they also only take one logic connection to control. Instead of populating the transistor that usually connects the IR receiver to the motor driver, [Eric] soldered jumper wires from each to an MSP430 chip (the G2231 that came with his Launchpad).

As you can see in the clip after the break, the first version of the code he wrote makes the robot follow a line as it would if it had not been altered. But there’s still plenty of programming space and several free I/O pins for future improvements.

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Insects Turned Into Orchestra; Not Harmed But Terribly Inconvenienced

August 31, 2011 by Brian Benchoff 28 Comments

[Jochem] has always been fascinated by chaos in nature, whether it’s a swarm of ants or evolution in action in a petri dish. His insect orchestra takes the chaos in the natural world and changes it into something completely artificial. In this case, MIDI.

For the build, a light sensor was placed at the bottom of a test tube. A cricket (or grasshopper, or locust) is then put into the test tube. The test tube is then closed up with a cap that houses a LED. An Arduino reads the light sensors and then transmits the data over MIDI. The MIDI commands are picked up in Abelton Live which converts everything to audio.

[Jochem] rigged up Abelton to have the insects perform in four different modes – instrument, synthesis, samples, and drums. Definitely an improvement over the humble Mexican Jumping bean.

You can check out the insect orchestra in action after the break.

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Making A Bluetooth Headset Into A Wireless Music Streaming Device

August 31, 2011 by Jeremy Cook 9 Comments

This bluetooth headset hack, although simple, may provide some hacking inspiration. Turning a Bluetooth headset into a wireless input for one’s stereo is definitely something that makes one think “why didn’t I think of that?” It’s also good if you’ve got a tight hacking budget as there’s not a lot of stuff to buy.

In addition to a possibly broken headset, a 3.5mm stereo plug and some wires are needed for this. Throw in some tools that every good hacker should have around like a soldering iron and glue gun and you’re ready to get started. [Dex] does a good job of describing the process, from disassembling the headset to wiring the stereo plug to it. When making the conversion, one must remember to bridge the left and right output channels, as most headsets only output a mono signal.

There’s not a whole lot else required to do this hack. Could be a good beginner project. For another Bluetooth-based hack using scrounged equipment, check out this Cellphone controlled retro-radio hack.

VGA Video Output With An ATtiny

August 31, 2011 by Mike Nathan 5 Comments

vga_video_attiny

[Fernando] is working on creating a game at home, with live scoring displayed on a large LCD TV. He’s keeping mum as to what the game entails, but he was more than happy to spill the details on how he planned to use the television as a wireless scoreboard.

The writeup is the first part in what will likely be a substantial series of progress reports, covering how he used an ATtiny45 to drive his LCD display. Eventually, the scoreboard will use a Bluetooth adapter for wireless input, but his immediate goal was to get the display running properly.

He explains how he uses the tiny micro and its limited set of I/O pins to drive the display, dipping into some of the technical details along the way. He discusses how he worked out the timings of the VSYNC and HSYNC pulsing, as well as how how the characters are actually drawn on the screen.

The article isn’t overly heavy on the technical details, and he has sample code available so you can take a look at how the VGA magic was done, so be sure to check it out.

Engine Hacks: The Kawaskai Voyager… V-12?

August 31, 2011 by Jeremy Cook 19 Comments

Although a V-12 engine is always nice, cramming one into a motorcycle definitely qualifies as an engine hack! [Allen Millyard], wasn’t satisfied with the standard number of cylinders (6!) on his already gigantic Kawasaki KZ1300. Like any reasonable person, he decided to graft two of their powerplants together!

In true engine hacker form, inspiration struck at a classic bikes show when someone said “Suppose you’re going to make a V-12 next, then?” [Allen] replied that it would be impossible, but after this conversation, he reportedly had to build one. By the time the show ended he’d figured out how to do it. Lots of work and two six-cylinder engines later, [Allen] had proven this task to be possible.

Although this may seem like a very extreme motorcycle engine hack, [Allen] has done quite a few motorcycle engine mods, making v-twins out of a pair of single-cylinder engines and a V-eight from two four-cylinder engines. Check out the video of his latest beast after the break! Continue reading “Engine Hacks: The Kawaskai Voyager… V-12?” →