Jan 29, 2006
Detect a metal or find RPM (revolutions per minute)
This sensor turns on when a metal get close to the sensor. This sensor can be used for not only detecting metal but also finding RPM of gear wheels.
where to buy
10 nF condenser x 1 / any component shop
5.7KΩ resistor (green, blue, red) x 1/ any compnent shop
LED x 1 / any component shop
470Ω resistor (yellow, purple, brown) x 1 / any component shop
Note
you have to attach a magnet behind the sensor to enable it to work. It will give different result wether you put S-N or N-S.
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