Hello, I am using the PI2Grover connected to a Grove Relay, set to Normally Open, to one of the digital connectors on the PI2Grover. As soon as I boot up, the relay is CLOSED (GPIO Pin is automatically set to HIGH by the boot process). The problem is that the relay powers a water pump and I don't want the pump running until the program tells it to run, not at boot up.
Is there anyway at boot up that I can set the GPIO output to LOW so that the pump won't run until a program sets the GPIO pin to HIGH? Regards, Dan
No, by the very nature of the GPIO 3.3V tp 5.0V voltage translation, GPIO lines (which by definition are floating on power up - that can go either way) will wake up as a 1, until initialized and set to 0.
You could put a pulldown resistor to ground(a 1000 Ohm resistor) on the output and that would take it it 0, until it is driven high.