I have been looking for an autovalve/compressor - and found one or two - the best in my opinion (as it doesn't run the rist of ruining the motor) and most compact by Sariel quite a few years ago.
But it clicks - click click click click - and it is virtually impossible to return the valve to neutral.
Not sure if anyone else has done an upgrade so I wondered if I could improve on it.
About this creation
Here is the result and it seems to work very well. It doesn't click, and it is possible to stop the valve at neutral. There is still the slight delay in the valve changing, but the delay is shorter than the time it takes to walk across the room to manually switch the valve
This model is a stand alone version with a bulky frame, it can be really compacted a lot - as I have just done in my next MOC.