Prototype on stripboard for R2’s smoke machine circuit. Needs trimming a bit, but works nicely. I2c controlled, with a variable duration from 1 to 9 seconds. It’s running at about 6v to produce a decent amount of vapour, so don’t want it running too long and burn out the coil. May do a PCB for it with the relay on board, as it is a fairly generic device so could be useful for other things.