Electronics, Lighting, & Gadgets - USB dynamo charging alternate from Martin's circuit?
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
How can one use Martin's circuit #7, #9, #10 with a usb alternative to charging?
http://www.pilom.com/BicycleElectronics/dynamo6sbp.gif
http://www.pilom.com/BicycleElectronics/dynamo2modeSynth.gif
http://www.pilom.com/BicycleElectronics/dynamo2modeVar2.gif
Unknown Cyclist
02-05-09, 03:36 PM
I think the LED voltage of those circuits might be a bit high for easily powering USB.
I guess it could be done but might not be very efficient.
I'm pretty sure I've seen (on here) simpler circuits with less LEDs, a battery and a USB out.
IIRC the battery (4.8V nimh) charges from the hub and stabilizes the USB output.
http://i143.photobucket.com/albums/r154/n4zou/lights/DynamoUSB-2.jpg
This circuit shows Martins single LED headlight circuit. Any of his circuits can be used in place of the single LED circuit shown. The dynamo can not power both the LED headlight and a USB device at the same time. There is not enough power produced to allow that. The USB circuit uses Ni-MH batteries to control voltage output of the dynamo and filter the power for the USB device. The 4 batteries must be solder-tab type and all connections must also be soldered. If there are any loose or open connections unregulated and unfiltered power will feed into your device seriously damaging it. You've been warned! Solder all joints and make absolutely sure the connections are perfect with no possibility of poor or open circuit conditions.