Can't come much simpler than this I guess?
As mentioned you can use an Arduino also.
Has the power to be programmable (use direct port manipulation).
For example produce 100 - 10uS pulses out every 10 seconds.
Maybe put a Pro Mini in a small box with FTDI out to the case for programming.
Also have a few outputs on a DB-09 female connector. 1HZ, 10Hz, 100Hz etc.
Add some PWM for servos.
Maybe a pot to vary the frequency.
LEDs, Bubble-Luscious ten minute air supply, wheels
Sorry caught in the moment.