whteglve:
Okay so here's the deal this is my first post on this forum. I'm also new to Arduino. I want to try and add memory seat and memory mirror features to my car which already has power seats and mirrors. I'd like to have the ability set the mirrors and driver seat to a certain postion, record it and return to that position at anytime. You know, like luxury cars have.
I plan on canablizing a switch that looks good with my interior for my inputs and adding some sort of sensor(s) to the motors involved. Should use a hall effect sensors? I'm not sure if I should use limit switches.
Any advice?
Yeah - don't let anybody else drive your car. That's what my wife and I do - we don't even like each other to drive our cars (granted, she's much shorter than I, and we certainly don't have luxury cars with powered seats and mirrors).
Likely, the motors already have either limit-switches or slip-clutches built in, so you likely are only concerned about positioning; that's going to be real tricky with the mirrors, but you are essentially going to need to use potentiometers in a voltage-divider arrangement to determine the position of the mirror (pan/tilt - so one pot for each axis) and the seat (once again, one pot for each "axis" of motion of the seat - however many that is). It will be tricky to implement on the mirrors because of space constraints. It will be less so on the seats (much more room to mount such components).
If you find that you don't have the room on the mirrors, but the mirrors do have some kind of limit switches (and not clutches), then you might be able to implement an optical interruptor on each motor; you would have to take the gearmotor apart, and find a gear in the geartrain that is large enough to drill one or more holes in, then mount a phototransistor/LED pair on opposite sides of the gear (or on a single side, and instead of holes, paint alternate black and white stripes). At startup, the Arduino would tell the motor to go to the limit of travel in one direction (home), then you would count the holes/stripes to determine position; this is how many homebrew CNC machines work, and it seems to work ok for them.
What I would do -first- though, is try to purchase a used mirror assembly (from a junkyard) and hack on that - that way, if you screw up, or find that you can't fit it - at least your car doesn't sit with a broken mirror and/or is unsafe to drive because you can't adjust the mirrors again. Plus you can get the practice on that mirror, and make your mistakes and discoveries there - then transfer the final design over to the actual mirror assembly on you car (plus, it is easier to bench test).
