Measuring resistance

Hello all,

This is a continuation of a project I started in the interfacing area (,101231.0.html). I am moving more into the electronics side so I figure it would be best to move it out of that area.

Short description is, I got an old DVD robot for free. The board in it was toast, after ripping the board out I put an arduino inside of it. I have stepper motor... well.. stepping fine, and now I am trying to figure out the sensors, which appear to be optical switches.

This is what the sensor wireing looks like, I think. Its a little tricky tracing this surface mounted board.

From what I can tell, when something breaks the lightpath, the optical switch opens. When closed I am getting a resistance of around 5.6k.

Now I need the arduino to detect this, but I am brain farting and can't seem to figure out how to do this. If anyone can give me some guidance I would appreciate it.


edit: That D1 doesn't look right to me, and its hard to tell where its going with the way the board is, so theirs a good chance that component isn't right.

After taking a nap, I figure it out, had to go back to basics and all that.