Gilad Lotan » wearable http://giladlotan.com/blog culture technology: bridging the gap Mon, 16 Jan 2012 02:03:09 +0000 http://wordpress.org/?v=2.8.6 en hourly 1 Hoodie Power http://giladlotan.com/blog/2007/02/hoodie-power/ http://giladlotan.com/blog/2007/02/hoodie-power/#comments Tue, 06 Feb 2007 06:27:24 +0000 http://giladlotan.com/blog/?p=106 Eric and I set out on a journey to create the ultimate experience for hoodie lovers. We wanted to make use of all that doodling around with the back and forth string movement of the hoodie, and actually generate electricity from that. We used a string with rare-earth magnets, going through a plastic tubing, which [...]]]> Hoodie-power
Eric and I set out on a journey to create the ultimate experience for hoodie lovers. We wanted to make use of all that doodling around with the back and forth string movement of the hoodie, and actually generate electricity from that. We used a string with rare-earth magnets, going through a plastic tubing, which had conductive coil wrapped around it. It was tricky to find the best amount of coils to fit a chosen number of magnets in order to maximize the electric charge produced. The following image shows the magnetic fields (created by the magnets being pulled from left to right on the middle string), creating electricity in the conductive coil:
electro-magnetism in the coil

Here are some of the measurements we got along the process:

  • 2 magnets, 1 coil => 5-10mV
  • 3 magnets, 1 coil => up to 20mV
  • 6 magnets, 1 coil => around 50mV
  • 3 magnets, 1 long coil (made up of 2 combined) => 40-50mV
  • 3 magnets, 2 separate coils => 70-100mV
  • 6 magnets (2 sets of 3), 2 separate coils => 150mV
  • 8 magnets (2 sets of 4), 2 separate coils => 250-290mV
  • 12 magnets (3 sets of 4), 2 separate coils => 300mV

What worked best in the end was to put 3 groups of 5 small magnets on the string, while having two separate coils of very thin magnet wire (the red one from radioshack). Each of those went into a rectifier (turns the AC current into DC), and with a capacitor in the circuit, gave us 1.8 V on average, definitely enough to light up at least four LEDs.
Simple Diode Bridge Circuit creating the coils form magnetic wire

video clip1

In order to take this project forward, we need to figure out better materials for the pipe. Instead of the stiff plastic pipe we got, we might try to get a more flexible pipe, smaller in diameter. The curve was difficult for the magnets path, and there was a lot of friction. This can be solved with the proper materials. We both feel like it will be great to actually get something simple working, so will try to continue and at least be able to have documentation of a made prototype.

]]> http://giladlotan.com/blog/2007/02/hoodie-power/feed/ 0