The board layouts

There are two board layouts, one of them - the output stage board - is used twice.

Output stages

This one has the following capabilities:

• 8 output stages with optocouplers, triacs and fuses
• coils and capacitors for each of them for radio interference suppression
• a bus driver to protect the outputs of the microcontroller

Download it in Eagle format.

Zero crossing and all the rest

The second board is used to achive all of the following issues:

• measurement of zero crossings
• provide 5V low-voltage for the microcontroller and the cooling fans with rectifiers, some capacities and the voltage regulator 7805
• 4 more output stages with fuses and optocouplers with internal phase syncronisation (on/off only)
• loop-trough of signals for other boards for better internal cable organization

Download it in Eagle format.

Microcontroller board

I didn't develop an own microcontroller application board here, but rather used a very neat and affordable one from Gigatechnologies, the USB I/O 24. More info in the microcontroller section.