Thank you Dave and Cad,
Dave, I've been looking into the Optos, and I agree that it would be the best idea for protecting the computers end.
Also, I checked out the Alatec website and found some good stuff but I guess at my entry level electronics know-how I am overwhelmed with this stuff.
Which Arduino should I get for this project at this stage in order to dechipher the voltages and pwm signals? It sounds like reading those might be difficult to do? Also I have priced Oscilloscopes... I feel like Id be paying for a high quality audio system without the amazing sound quality lol. I saw some cheap versions for 140$ I am interested in that, but at those point I have to find out how the treadmill is sending out the signal and I think to do that I need the Arduino.
CadCoke, I am not For sure that my pwm signal for the motor control specifically is 0-5. It could be for the incline, I had assumped they were both similar in operation. I have to do some testing. Any recommendations on which arduino to get in order to intercept the signals?
I was thinking the Uno R3 would be ok but the Mega looks tempting. I dont think I will need that many pwm signals either.