AVR-Chat

--- In AVR-Chat@yahoogroups.com, David VanHorn <dvanhorn@c...> wrote:
> At 07:30 AM 6/28/2004 -0700, jay marante wrote:
> 
> >when i power-up my MCU, is it possible for me to know the position 
of 
> >my servo motor if it is in a 0, 90, 180, etc, degree? how?
> >TIA
> 
> For remote control servos, no. There's no positional feedback.
> You could ADD a sensor.


Most hobby servo's have an internal pot or encoder that feeds the 
internal circuit a posistion feedback.  It is used as one of the 
parameters on how fast it needs to move to posistion.

It may be possible to add an op-amp to the pot to get a value from 
that pot.  But, since that pot is part of the internal circuit, it 
would be prudent to really understand the circuit on the board.  
There may be a place you can pic off an amplified value that would 
not interferre with the signal.

The add-on would be to add a 10k pot to the shaft and use a voltage 
divider or RC pulse to get a value.

Dave