Let me get straight to the details: I would like to use the Arduino board (which has been collecting dust for over a year) for a fun but possibly ambitious project: Custom Climate control in my car. I do, however, need some hardware help.
Brief project description (the very first steps. I have some plans to expand it if all goes well): 1. Read inside temp from a sensor (LM35, arriving soon). 2. If temp is above threshold: a. Turn on fan. b. Turn on AC - bypass stock controls in both cases 3. Once temp is at or below threshold - turn everything off
Don't worry about threshold and other programming details. That's the easy part for me.
Here's the difficult part: turning on the fan. My car has a knob with 4 speed settings. As I understand (and I am not very good with electrical hardware, but would love to learn), depending on the speed setting, the output current varies. However, I have no idea what type of device I should use to simulate this behavior. Any ideas? Perhaps someone has done something similar? Keep in mind, I don't actually need to control a motor or anything, but basically simulate output of the Fan knob.