I'm considering my first proper Arduino project. I've got a fairly cheap exercise bike. The bike is great, but the LCD readout is hopeless, and there's no way to connect it to a PC or anything. I'd like to change that.
The interface between the bike and the display unit is very simple - it looks like a standard 3.5mm audio jack, and I'm hoping that the signal is similarly simple. The problem is I'm not really sure if there's a safe way to figure out the signal format without blowing up my board. Can anyone recommend a circuit layout that'd let me figure out the format without causing damage to my board. All I really want to start with is to safely connect the 3.5mm jack to an analogue input and monitor the values. Is that even possible without figuring out the voltage/current with an oscilloscope first?
I'm comfortable enough with the software side, I'm just not sure where to start with the electronics.
Any help much appreciated, Rob.