"Cannot read or The analog reading is always 0" 【SEN0203/SEN0344】

1. Check whether the code wiring is correct;
2. Whether the use method is correct, pay attention to use the strap to tie the module to the finger, and do not press the back of the sensor with your hand;
3. Check whether the plastic film on the sensor is in good condition, without plastic film SEN0203 can not work (it can be replaced by transparent tape)

Note:It is recommended to fix the probe on the finger pulp when using the test