DIY Solar Panels

September 8, 2009 by James Munns 74 Comments

solar

Reader [unangst] pointed out to us an article in the U.K.’s Daily Mail, where a teenager from Nepal had managed to create a 9v, 18W solar panel using human hair rather than the usual semiconductors (usually crystalline-silicon). The complex silicon in solar panels are what keep the prices out of reach of developing nations, and while there are a number of new technologies that are helping bring down the cost, [Karki] managed to make his solar panel for only £23 (roughly $38). He also claims that when mass produced the price could drop substantially down to under $10 a panel, which would shatter the $1/watt sweet spot.

The melanin in hair acts as an organic-semiconductor, and while the hair does not have the longevity that silicon panels have (months rather than years), these panels can be made cheaply and serviced with little to no complex knowledge. Using melanin as an organic semiconductor seems to be a newer idea, because information seems hard to come by, but we managed to find a research paper from 2007 that explored the energy absorption attributes of melanin, as well as some good background info for the science types.

Research Paper (Warning: PDF)

So, Hack a Day readers, which one of you is going to make your home-brew solar panels first? Let us know when you do.

Thanks [unangst].

[digg=http://digg.com/environment/Teenager_Makes_DIY_Solar_Panels_from_Hair_Hack_a_Day]

Variable Range Sprinkler

September 4, 2009 by Devlin Thyne 14 Comments

[vimeo http://vimeo.com/6409575 w=470&h=352]
[Pete], a musician, and the guy behind SparkFun’s pogobeds and locking footprints has a sprinkler hack. He wanted to keep his dog, Choppy, happy with a green lawn while also keeping his sidewalk water free. To solve this problem, he hacked his sprinkler and hose to adjust the sprinkler’s range. He uses an Arduino to read a potentiometer signifying the direction that the sprinkler is facing and a servo to adjust a hose valve that controls the sprinkler’s water flow. Be sure to check out the video above to see it in action.

Wireless Electricity

August 28, 2009 by Mike Szczys 78 Comments

[ted id=619]

[Eric Giler] has a talk available over at TED that discusses and demos delivering electricity without wires. Called WiTricity, these methods were developed by a team at MIT a few years ago who were working off of the concepts of Nicolai Tesla. The facts shared about our current energy delivery system are a bit shocking; we’ve spent over $1 trillion in infrastructure and produce more than 40 billion disposable batteries each year.

The demonstration in the video starts about 6:30 into it. At first we see a flat panel television powered wirelessly from about 6 feet away, then the T-Mobile G1 powered from the same distance. The thought of new TVs coming with WiFi and WiTricity standard would mean just hanging it on the wall with no cords to run. We can also image cellphones that have a battery only for backup purposes when you were not near a transmitter.

The power transfer occurs between two coils that resonate at the same frequency and only that frequency. This remind us a bit of Orson Scott Card’s fantasy communications device from the Ender’s Saga.

Energy Efficient Fridge Hack

August 27, 2009 by James Munns 39 Comments

Green_Freezer

We’ve already covered a pipe bomb mini-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.