The Ventilator Controller

here I like to spend few words about the ventilator controller I have created. I bought two ventilators which need 220V to drive its motors. Probably I could have used something commercial to switch and drive them, but I wanted to use CAN. Therefore I decided to create my own circuit with mikrocontroller, CAN interface and 220V drivers for the ventilators. 

 The mikrocontroller

I used the same type of mikrocontroller as for the one-wire controller: AT90CAN128. It has a CAN interface, which I knew how to use. The PCA82C250 I use for the CAN transceiver.  

The power supply

The power supply contains the same chips as for the one-wire controller. The step down contoller
LM2575 converts 12V DC to 5V DC and drives the digital chips. The 12V DC comes along with the CAN bus cable, which I have installed inside my basement.

The 220V drivers

To drive the ventilators, I use two S202 S12 solid state relais. Each relais contains a digital input, which can be directly connected to the mikrocontroller. I also added varistors and fuses for circuit protection.

Below a picture of the circuit I created. The red lines indicate the chip positions.