Hi
I've got a broken controller board on a Mitsubishi dehumidifier and rather than try and source (pay for) a new board it seems ideal for an Arduino project.
The schematics show two main boards, one with all the mains power relays etc and the controller board which is isolated from the mains and relays on the power board. So for connecting up the Arduino and switching mains it is pretty safe and already isolated.
The Arduino needs to control:
- A solenoid (simple 12v relay)
- Stepper motor for the louvre, although not worried if this is working or not
- Compressor motor (simple 12v relay)
- Fan motor, uses a solid state relay type AQG12212 which is a random crossing relay
It is number 4 that I'm not sure about. The fan has about 4 different speeds but is only wired by two wires. I'm guessing to produce the slower speeds the solid state relay is being turned on and off at the right time in the mains cycle. The schematic shows the micro-controller having an un-smoothed input from the transformer secondary winding into an interrupt pin, and I would think this tells the CPU where the mains cycle is in order to regulate the fans speed.
My question is, how can this be achieved with the Ardunio?
A schematic is available here in the service manual http://www.melco.co.nz/oasis/data/service/MJ-E16SX-A1.pdf
Best Regards
Phil