I've got a patio shade (big) that I'm powering with a power window motor. I'm trying to figure out ways to automate it, but because it's just a "dumb" motor, I need to come up with a system of letting arduino know the shades relative position.
The basics. Currently there is no Arduino. The motor is powered by two relays and two NO pushbutton switches. Push one button, the shade goes up. Push the other, current is reversed and shade goes down. I like this circuit, because I can power the motor "manually" with a 3 cell lipo and the voltage is isolated from the future Arduino circuit (I may use a UBEC to power the Adruino from the same battery). My plan is to tie the Arduino to two relays that can momentarily close the pushbutton switches (up/down).
Again, the problem is the Arduino has no idea what the position of the shade is, so I'm just looking for some ideas. Here are mine so far...
micro switch positioned either on top or bottom where shade base passes.
IR transmitter/receiver positioned either on top or bottom where shade passes.
Ultrasonic sensor (I like this cause I have one, although it seems overkill).
and was also wondering if it was possible for Arduino to monitor current to shade motor - as shade get's heavier (moving up), current/resistance of motor must increase, so this could also be a way to determine shade position.
Obviously a stepper motor would be better, but the power window motor, which is geared works great.
Anyhow, any other thoughts would be great.
Thanks in advance!