Pulse Motors: Supplement: Hall Sensor + OpAmp Sensitivity
I added a small 0.1 uF ceramic cap from the sensor output/opamp inputs to ground. This eliminated spurious triggering from the ambient RF and improved stability. Also added a 47uF cap across the main power entry, just because.
The apparatus can now be adjusted to incredible sensitivity. The small ferrite magnet can switch it reliably at over 10 cm distance. And this is still working the op-amp in comparator mode, not amplifer!