This question is an exact duplicate of:
I am having troubles setting a simple Relais to On and Off. My code is quite simple:
GPIO.setup(RELAIS_PIN, GPIO.OUT) GPIO.output(RELAIS_PIN, GPIO.HIGH) time.sleep(2) GPIO.output(RELAIS_PIN, GPIO.LOW)
now when this runs it puts the pin to high correctly, but not back to low afterwards. i.e. the pin stays high forever or in other words, the relais opens but does not close.
i have tried this with multiple pins and they all show the same behaviour.
When measuring voltage between one of the 5V pins and the output pin with a multimeter, it shows that the pin has 5v when high and 1.7v when low. shouldnt it be 0v when low? i guess that 1.7v is enough to keep the relais open? could 5v-1.7v = 3.3v mean something?
Is this a problem of the relais or of the pi?