This new version is actually working with the firmware v1, found on my webpage.

The problem I am facing is heating of the 100ohm resistor in the power supply section, as well as ringing (buzzing) of the capacitor connected in series with it. This is due the "reverse piezoelectric effect". When capacitor is charged during normal operation, and when I trigger the triac it basically shorts the supply rails and discharges whatever is contained in the capacitor. This heats up the resistor and forces capacitor to sing/ring/buzz :-)

If there was only a way to use that energy for something useful instead of heating the resistor...