RL-HSB-001 · Sensors · Hall Sensor Breakout
Troubleshooting
Common wiring, saturation, supply, polarity, thermal, and noise symptoms with fixes.
Published May 4, 2026Updated May 8, 2026Reading time ~12 min
01Symptom table#
| Symptom | Likely cause | Fix |
|---|---|---|
| LED off | Reversed VCC/GND, no supply | Verify pin order against the silkscreen and re-power. |
| Output stuck near VCC or 0 V | OUT shorted, ADC pin mis-wired, or saturating field | Disconnect ADC, measure OUT with a multimeter, and remove the magnet. |
| Reading drifts with supply ripple | Non-ratiometric ADC reference | Power VCC from the same rail as ADC VREF. |
| Flips sign vs expectation | Magnet polarity or facing | Flip the magnet or negate in firmware. |
| Reading drifts on warm-up | Thermal offset of IC | Re-zero after more than 60 seconds and on every cold start. |
| Noisy reading at idle | Long unshielded cable, switching supply | Add 100 nF at VCC, shield cable, and oversample 8-16x. |
02Fast isolation flow#
Start by measuring VCC and OUT with a multimeter before debugging firmware. With no nearby magnet, OUT should sit near VCC / 2; if it does not, remove the ADC connection and test the breakout alone.