Make a spring loaded aluminum handle lever and mount a magnet on it by the hinge point. Then using a Hall effect sensor such as Micronas HAL805 (which outputs an analogue voltage) use the A/D converter (I suggest 10 bits converter) to read the voltage and convert it to a PWM signal that varies from 10% duty cycle to 90% duty cycle. The Hall effect sensor detects the change of magnetic field as the magnet moves produdes the analogue voltage on proportion to this change. The microcontroller program will translate the analogue values to the PWM duty cycle and produce the appropriate waveform using a timer. See little picture for concept.



Some things to consider....calibrate the device so that the rest center position of the device equals 50% duty cycle. Put stops to limit how far the lever travels and calibrate the end point so that the PWM duty cycle equals 10% and 90% at the left and right lever stops. I suggest the round magnet needs to be magnetized with the N/S poles split being across the diameter of the circle and position the magnet so that this split line is purpendicular to the hall cell when the handle is in the center position.

Michael Karas