[bugloaf] tipped us off about this flower power hack. University of Washington researchers, [Babak], [Brian], and [Carlton] have developed very low power circuits to run directly off of trees. This builds upon the work of MIT researchers and Voltree Power. A voltage of up to around 200mV is generated between an electrode in a tree and an electrode in the ground. Identical metals can be used as electrodes as the process is not like that of a lemon or potato battery. The significant development here is the use of a boost converter and exceptionally low power circuits. What kind of applications can you come up with for this source of power? Maybe you could try to combine this power with the power from donuts and hair.
We’ve already covered a pipe bombmini-fridge this week, but inventor [Tom Chalko] provides us with today’s fridge hack. He noticed that chest-style (laying down, see above) freezers were more energy efficient when compared to normal stand up refrigerators at the same size, despite the colder temperatures involved. This is largely due to the fact that these chest-style freezers keep cold air in like water in a bowl, even if the lid is open. He has written a very thorough report on his findings (pdf), as well as a detailed walk through of the manageable task of converting a chest-style freezer into a chest-style fridge. In the end, his fridge only used 103 Wh of electricity on the first day to reach and maintain between 4° and 7° C (39° to 45° F), and he noted that 30% of that was just getting it up to temperature. After that, the fridge only turned on for roughly 90 seconds an hour, making it a very quiet fridge as well.
[Mike] really liked the thought of the Monome, especially the green aspect of their construction. He felt he could take it a step further. After 40 years of electronics tinkering, he had quite a spare parts box. He constructed his monome clone from stuff he just had laying around. All of his pieces were either rejected samples from his company or outdated parts destined for the trash bin. Great job [Mike]. If you are planning to build one and don’t have the buttons laying around, you can get a more typical monome look and feel by going with the sparkfun RGB pads, like we did back in March.
[Roland] recently graduated from UC Berkely. For his graduation ceremony, he wanted to do something unique. He built a diorama on his graduation cap depicting a house driven from alternative energy. The whole thing is solar powered. The wind turbine is actually powered from the solar panel, and with a remote control, he can make the sun rise and set.
Recycling is great. We’ve seen a pretty hard push in that direction recently. We like the fact that our modifying of hardware is generally saving it from the dump. Keep in mind, that just using old hardware can be advantageous too. We don’t always need the new shiny thing, maybe we’re fine with what we’ve got. That is exactly what lastyearsmodel.org is about. You can join their facebook group and even get stickers for your old devices.
[Murray484] submitted his instructable on how to create a stepper motor controller from an old scanner. He removed the motor and controller from an old scanner then harvested the parts. He’s pretty much starting over, taking the ULN2003 chip from the scanner motor controller and putting it on a fresh board. He then wired it all up, installed the software and got it working. Finally, he built a container out of cardboard for it all. Though he could have made it nicer looking and used higher quality building materials, he was trying to make this a “green” project for the epilog laser cutter contest. He’s done a good job recycling, this could be pretty useful.
You probably saw [Phillip Torrone] and [Limor Fried]‘s twittering Kill A Watt earlier this week. It was an entry in the Core77/Greener Gadgets Design Competition. We saw a little bit about how it was assembled, but now they’ve posted a full guide to assembling the hardware. Each Kill A Watt gets an XBee radio that transmits back to a receiver that logs the power usage. The difficult part when putting this design together was the XBee required 50mA when transmitting. This is well above the Kill A Watt’s internal power supply. They remedied this by adding a 10,000uF supercap to act as a rechargeable battery. The daily twittering is just a side-effect of the project. The Kill A Watts transmit every 2 seconds, so you’ll get a very accurate report of your power usage. This is a great project for renters who can’t permanently modify their power infrastructure. Each Kill A Watt can support quite a few appliances since they’re rated for 15A, ~1800W.
[rog8811] sent in this really cool hack where he used the optics sled from a PS3 as a foundation for a 7 color hand held laser projector. Combining a green laser, a blue ray laser, and a red laser, he is able to produce a variety of color including white. There are step by step instructions on how to make a multicolored laser. He then goes even further, showing how to integrate this into a hand held projector with pre programmed patterns. You can see some examples of the different colors and patterns in this video.
