bang bang servo contoller

Hello everyone. I am new here and to electronics but would like to learn and would appreciate any help. I am trying to create a bang bang servo controller using two pot's, one for the setpoint and one for feedback. I was told I need a lm393 comarator and a 74hc14 oscillator, a 100k resistor and a .1uf capacitor. This should give me 100 pulses/sec when the pots are out of phase. I am trying to make a servo controlled water valve to control a engine dyno so I need to modulate the valve all the time while the test engine is runnning. This is going to replace a cable system that is there now, lots of backlash. I need help drawing up the circuit and where to get parts, thankyou.