First Large-Scale Urban Bike Sharing Program Launches in Denver!

Yesterday the city of Denver celebrated Earth Day by launching the first large-scale bike sharing network in the US! Dubbed B-Cycle, the program offers offers roughly 400 red Trek B-cycles at 40 B-stations throughout the City. A launch event at the City and County buildings kicked off the program and afterward the Mayor of Denver, John Hickenlooper, led a bike parade around the Civic Center Park.

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Generate electricity with a candle

What you see above is a generator that converts heat to electricity. [Reukpower's] thermoelectric lamp is one of those hacks that makes you scratch your head even though you understand why it should work. The heart of the system uses a Peltier cool, just like the thermoelectric solar generator. When there is a temperature differential from one side of the Peltier to the other a small current is generated.

In this case a candle heats one side and a heat sink cools the other. The tiny voltage picked up from the Peltier’s contacts is then boosted using a joule thief. We’ve seen LEDs powered with a joule thief before, benefiting from their own low power consumption. In this case, the boost circuit is scavenged from an emergency phone charger and probably achieves higher efficiency than if he had built it himself.

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Aerodynamic tail makes Geo Metro even cooler

[MetroMPG], an environmentally friendly car enthusiast from Ontario, added a tail to his car to increase gas mileage. This 1998 Pontiac Firefly is a sibling of the cheap and popular Geo Metro. He had already done some work to cover a portion of the rear wheel wells to reduce drag. Using cardboard, duct tape, and an aluminum frame he extended the rear of the car by around six feet.

The results are pretty impressive. His extensive testing can be seen in the video after the break and reveals a Miles Per Gallon increase of 15.1% at 90 km/h to get to 64 MPG. The tail is removable but we’re thinking it’s a pain to keep relocating the tail lights from the original body to the removable one.

Now we’re wondering if someone is doing this to our Smurf-blue Metro that we sold to the junk man for $100 back in 2001. It ran great, if you weren’t caught in the cloud of blue smoke coming out the back.

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C-clamp current monitoring

[Hydronic] did some tests to make his own current sensor using a c-clamp wrapped with wire. He tried several different cores including an aluminum carabiner, the C-clamp, and what he calls a u-lock (removable chain link). There is some success here that could be improved with cleaner winding and by adjusting readings based on the length of wire used in the wrapping.

This did make us perk up a bit right off the bat. Reader [Mure], who tipped us off about this, suggested that this could be used to make your own Kill-a-Watt without including it in the circuit. We made the jump to house monitoring. We’d love to have a data tracker for our home circuits to curb wasteful energy use. Perhaps we’ll try to make our own sensors and produce a diy Cent-a-Meter.

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Solar Water Heater

[Jake] built himself a solar water heater. The system has an 82 gallon insulated water tank and uses a solar collection grid made of PVC pipe. As the water heats, it rises to the top of the collector and runs into the tank while pulling colder water from the bottom of the tank back into the collector.

A sunny day yields temperatures around 130 degrees Fahrenheit. On a cloudy day the water can still be heated to about 90 Fahrenheit. This is about 19 degrees cooler that one might desire but the difference is made up by an electric shower head that heats as the water comes out. [Jake's] system, seen in the video after the break, allows him to forgo the use of electricity on sunny days, and reduce its use by around half on cloudy days. Read the rest of this entry »

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Power generating backpack

In the military, you have to carry tons of stuff. This is something we hear and see all the time. They are always trying to come up with ways to reduce the weight or quantity of the things that you bring into the field. This power generating backpack harnesses the natural up and down motion of your steps to produce power. This could reduce the amount of batteries carried into the field greatly. That’s what they say anyway, how many batteries do soldiers normally carry around? Aside from that point, we think it is pretty cool. We could see using this to keep our cell phone or GPS charged on long hiking and camping trips. You could also build something of your own to work similarly.

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Hacker rewarded for creating electricity

[garhol] tipped us off about a self-taught hacker who brought a little light to his tiny home. [William Kamkwamba] dropped out of school because his family lacked the $80 per year for tuition. At the age of 14 he read books from the library and gained the knowledge he needed to built a 12 watt wind generator from junk parts. Wow!

We’re pretty used to hearing about creative people who end up getting punished for their hacks. Fortunately he has been rewarded for his brilliance. He’s now studying at the African Leadership Academy in Johannesburg with a well-deserved scholarship.

His story comes to the surface now because a book about his experiences has just been released. We need more people like this, and they should be rewarded for their efforts like he has been. We’ve put the book on our hold list at our Public Library and can’t wait to gain some knowledge from [William's] experiences.

Check out his short talk at the TED conference, embedded after the break. Read the rest of this entry »

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Growing algae with an Arduino

We’ve seen automated grow boxes of all shapes and sizes, but all were for growing plants. [Jared] over at Inventgeek wanted to do something similar for his algae. He started off with an Arduino-based solution that allows the controlled pulse of LEDs connected to his standard bioreactor as a prototype. Once he determined his proof of concept worked, he began work on a design based on the Arduino Pro Mini that has more advanced features such as temperature monitoring and algae culture density monitoring via some fancy IR voodoo. The code is open source and the hardware is easily obtainable, all that remains is the desire to grow algae.

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Variable Range Sprinkler

[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.

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Seawater cooled data centers

Remember Mauritius from High School geography? We didn’t either, but apparently it’s a small island nation east of the southern tip of Africa. It seems they are trying to develop an industry in eco-friendly data centers. The plan is to use a pipeline to gather cold water from the ocean, run it two miles to the island, and use it as inexpensive cooling. Because rooms packed with servers generate copious amounts of heat it’s easy to see how this can reduce the cost of maintaining a data center.

The thing that struck us here is, how eco-friendly is this? The article mentions that this technology is fairly mature and is already used in several places. With that in mind, isn’t this just another way to raise the temperature of the oceans, or does the environmental savings of not using electricity or gas to produce the cooling offset this?

[Thanks Vesanies]

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DIY Solar Panels

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].

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12kW solar collector

Though not much info is readly available about it on the web, [Joe Carruth] is trying to build publicity (and venture capital) for his home-built solar electric generator. At its essence, it is a Stirling dish system with an adjustable composite mirror surface. This means that instead of having to rotate the entire contraption in order to follow the Sun, [Joe] only has to make the mirror segments pivot. A Stirling steam engine at the tip converts the energy into the movement used to generate electricity. Solar power plants (or ‘farms’) that are emerging are beginning to consider the advantages of using more efficient Stirling dishes rather than less efficient solar panels. If anyone has an idea as to how [Joe] can automate sun tracking for the mirrors, please post it in the comments. A couple more videos on the topic (in general) are available below: Read the rest of this entry »

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Tapping Tree Power

[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.

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