# Small Coil/Magnet Supplies ~ 3 Volts ~ 0.1 Amps

B

Jan 1, 1970
0
The "Firefly" sells in bicycle shops for about $8.00. It's an LED + watch battery that attaches to the rim ends of spokes and creates a pretty noticeable marker or running light. The problem is the battery runs down. Couldn't a small coil + rectifier + capacitor + LED be placed on the spoke ends with a magnet on the forks or chain or seat stays? The wheel itself would become a generator. What kind of small coil would put out 3 volts/0.1 amp when swiped with a magnet at speeds > 5 mph? Bret Cahill A #### Andrew Howard Jan 1, 1970 0 BretCahill said: The "Firefly" sells in bicycle shops for about$8.00. It's an LED + watch
battery that attaches to the rim ends of spokes and creates a pretty noticeable
marker or running light.

The problem is the battery runs down.

Couldn't a small coil + rectifier + capacitor + LED be placed on the spoke ends
with a magnet on the forks or chain or seat stays? The wheel itself would
become a generator.

What kind of small coil would put out 3 volts/0.1 amp when swiped with a magnet
at speeds > 5 mph?

I guess I f you just got one that was enough to produce over 3 volts, you
could probably regulate it, so speed changes wouldn't matter. I don't have
much experience, so I don't actually know what specific coil you would need
though.

Andrew Howard

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