Piotr Zapart designed this board to overcome range issues when using traditional 300 degree potentiometers or Hall sensors as rotational angle to voltage converters:

HALL Preamp/Analog axis calibrator

The idea was to create a device that will perform an axis calibration, usually done in digital domain, but before sampling the signal in the ADC, still in analog domain, using it’s advantageous infinite resolution

 

the main function of this device is to:

• Buffer the analog output signal coming from a potentiometer or another rotary angle to voltage converter like ie. Hall sensors.
• Filter out the high band noise and limit the bandwidth to an usable range only, protect the input against voltage spikes.
• Match the output voltage range of the source (pot/hall sensor) with the input range of the ADC, thus making the most of the available ADC resolution.
• Linearize the hall sensor output signal response by amplyfing it’s most linear region to the full scale ADC input range.

The board is shared on OSH Park:

HALL Preamp