Ok so not the best schematics but the more i though about it the simpler it became.
These were just thrown together over dinner (its 11:30pm here) so not all that tidy ill cad up something better if anyones interested latter, but you should get the jist if you want to build it yourself.
I also snapped the servo-> valve for you Jens, I can understand where you coming from that a STDP (or STQP if your switching signals) and servo is the "easiest" solution and trust me ive done worse, eg servo's to push buttons to control hi current loads but its fiddly, at least this way it works or it dos'nt besides building this part of the board is just the beginnings, add some flipflips and you got lights, flux capacitor and you've a time machine.
anyway its late, enjoy
also quick update on the microcontroller project, am reworking the prop protocol but currently all prop 8ch's do something...sometimes.. with the lights controlled via a custom board from the GPIO's still waiting on cash for radios though.
http://youtu.be/6-SPS1VTHB0