Pierre Coupard, the genius behind the amazing Linux/RTAI based software radio, now brings us this interesting article that explains how you can build an environmentally friendly uClinux system that is powered by a hand-operated crank. Look ma, no batteries!

Coupard writes . . .

Have you ever thought it'd be cool if you could have an environmentally friendly computer?

I've always wanted one. I even powered my old ZX81 with a bicycle, a dynamo, and a bridge rectifier once. Trouble is, even the poor little ZX81 needed a lot of pedaling to simply boot up.

Then, one Friday, I came across this hand-powered lantern while browsing the net, and an idea clicked in my head: the manufacturer of this little gem ships it with a 3V @ 650mA light bulb (1.95 W), and the uCdimm from Lineo needs 3.3V @ 350mA (1.16 W) at most, so the generator within the lantern should be able to power a uCdimm confortably.

So I called up a bunch of places here in Toronto and found one of these lanterns. When I came back to the office, our local electronics guru Sergey, our local geekhead Evan, and I took the thing apart, cranked up the spring and measured the voltage. Without the lantern's battery and light bulb, the internal DC generator spews out a heroic 5V.

Cool, that's perfect for a 3.3 V regulator and a uCdimm!

So I spent the weekend ripping the guts out of the lantern (it's surprising how much electronics the thing had inside), installing a 3.3 V regulator inside, a serial port and an Ethernet port at the back, rewiring the power plug that used to serve as a battery charging port to power the uCdimm while working on it, and rewiring the button (that is also a clever brake to stop the spring from unwinding when the lantern is not in use).

The hardest part was soldering a bunch of wires onto the uCdimm's bus (man, those connector pads are tiny!) and installing it nicely in lieu of the original light bulb and reflector.

One nice thing about the uCdimm (apart from its low power consumption, of course) is that it boots into Linux quickly — which is crucial because the dynamo only provide a little over 2 minutes of power with 60 cranks, so every second spent booting up the board is a second lost that can't be used to browse.

So here it is: the “uCdynamo”, the first webserver you can bring with you and use in a desert :-)

Note the uCdimm embedded in the lantern's front bezel, in the above photo.

The above photo of the side of the lantern shows the “business end” of the muscle power supply — the hand crank. A button (more easily seen in the next photo) controls the brake applied on the generator's large pulley, and also drives the reset line on the uCdimm at the highest setting. A power LED mounted next to the button was rewired to serve as a “health” monitor, just like on Lineo's uCevolution board.

Note the serial port, Ethernet port, and added power plug sticking out at the back of the lantern, in the above photo.

The above photo shows the “guts” of the beast. You can see the gears which demultiplicate the huge torque and low speed of the unwinding spring into a low torque, high speed rotation to operate the generator.

Jeff Dionne reckons the generator has enough oomph to power an LCD display as well, and there's plenty of space left on the side of the lantern to bolt one on, so maybe we'll turn it into a hand-powered “handheld” some day :-)

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Copyright © 2001, Lineo Inc. All rights reserved. Reproduced with permission.

 
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