Input adapter for filament sensor

thingiverse

This compact interface board enables you to link the filament width sensor to a temperature input. Some 3D printer controller boards lack standard-purpose analog (A to D) inputs, so this board adjusts the signal, allowing an available thermistor input to be used. A prime example of where this is useful is the Rambo Mini board. To make use of this adapter, some work still needs to be done to update Marlin firmware and allow this option. This adapter employs a small op amp in a voltage follower circuit. It reduces the output impedance of the signal so that it can supply the current needed by the thermistor input. Without this adapter, the filament sensor's output is loaded by the thermistor input, resulting in an inaccurate output. This adjustment is not necessary for standard-purpose analog inputs since their current draw is very low.