Thread: Plugin for in/outside temp monitoring

Originally Posted by WuNgUn

So I'd need a servo to operate the temp dial and a servo for the vent selector...the fan speeds, rear defrost and A/C can be controlled as analogue outputs I'm assuming?

You could put a servo on the actual dials, or on the shaft of the door the dial controls, if you do it that way, you might want to try using masteros Aircon.

Rear defrost - Digital out/relay as no analog control is needed.

AC - the compressor would just be a digital out where you find the "AC request" lead from the existing controller to the ECU.

The blower motor is an analog thing, but:

It also draws something like 30-40 Amps.. Which is way, way, way too much for any of the controller I/O cards we're talking about on thier own.
If your setup has a blower resistor, you can just use some digital outputs to operate relays across the sections of the resistor. For variable speed, there are some more options, but from here it gets more custom. A power resistor can be controlled with a low power analog out (fusion has been working on one for a bit, I'm personally waiting on this patiently with my fingers crossed). Some power resistor/fan setups use Pulse width modulation, which is no good. I mean it's great and effficient and all, but there are not many PWM control methods available to us. I'm finding that a Honda power transistor placed in the air stream, like a blower resistor is a good solution, as it uses a direct analog votage control input.

Originally Posted by WuNgUn

Then have it monitor interior temps, and have the PC control fan speed/temp to maintain the selected temp...
Am I missing anything else?

Well that all depends on how "OEM" you want the control to work:

If all you want is "manual control" it's pretty straight forward. but if you want to be able to make the output temperature what the dial says with any accuracy, or even better you want it to control the actual interior temperature accurately. You have to account for sunload and ambient losses, & not just have it react temperature changes. Otherwise the control wil be all over the place, like a roller coaster. There are many other aspects of automatic control that I am presently working on, if you have any more specific questions (even vehicle specific) or ideas I'd be glad to lend a hand and share my experience. You might want to check out my modernity thread in the skins subforum of the fusion subforum, here. And also my Automatic AC control thread in the fusion subforum directly.