Hi all, perhaps someone can help with a wee power problem. I've
got a circuit board mounted on a motor shaft. The circuit is there to
measure the movement of an escapement mechanism (kind of
like a governor) as the shaft turns from 100 to 3500rpm. The
circuit itself is not a problem, I've managed to attached a small
slider pot to the escapement and it's measuring OK with an ADC.
What I'd like to do is induce power to the circuit using some kind
of magnet/coil system. I need around 15mA at 6VDC. A possibility
is to use a 7-segment LED (synched with the rotation) to indicate
the escapement movement, hence the power requirement. Using
batteries is not really an option because of the duration of the
measurements and particularly if the LED idea goes ahead. I've
got plenty of envultured materials - strong HDD magnets and
more scrap transformers (enamelled wire of all gauges and
laminate cores) you can shake a stick at. I thought I may be able
to attach a small DC motor to the main motor's shaft as a
generator but that's proved too tricky because of space limitations.
So, any ideas on the most efficient way to induce power into coils
on the PCB from stator magnets ?

TIA

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