climate controled by mac

**jstick81** · 01-17-2008, 01:29 PM

Hi, I am putting in a new mac mini and touch screen in my jetta mk4.
I would like to control the hvac controls on the touch screen. Is there is anyone who has done this. Any pointers would be helpful, thanks.

**Jirka Jirout** · 01-17-2008, 04:54 PM

Yes, I have done it in my Tatra and I am re-designing the installation right now. The first version worked with custom RS232 relay board, the new one will use Phidgets 8/8/8 interface board. The original version only used fans (total of 5) to control the air distribution, the current one will use 3 model servos to move the air ventils. I will only use two fans - one for the airco evaporator and one for the heater (the Tatra has a rather complicated and *separate* heating and airco systems).

One problem I am facing now is a good way to regulate the fans. Switching resistors using relays or FETs works well, but I would like to use PWM. Unfortunately all the PWM circuits I was able to built to to date generate a lot of audio noise that I don't seem to be able to eliminate completely.

**jstick81** · 01-17-2008, 05:10 PM

I did find this while searching the web. Not sure if it works with mac.

**Jirka Jirout** · 01-18-2008, 02:11 AM

There is no reason why it should not work - it is using a standard RS232 port, so cou can connect ti to Mac using one of the many RS22-USB adapters and write/read data using NSFileHandle the same way you use for files or other serial devices.

What is nice about this particular board is that some basic functions are implemented on the hardware level (such as the compressor cut-off).