I noticed an occasional random button press with the grove_switch_relay.py example.
The relay would click (as if the button was pressed) randomly a few times a minute.
I then simply unplugged the switch from the 20 cm cable. The problem got much worse.
I then swapped out the relay for a LED, and this showed similar problems. The push button switch, LED and relay are the standard starter kit components.
It appears that all it takes is a 20 cm cable to act as a very effective antenna that then randomly takes a digital input high or low.
I do have a number of other WiFi devices on my test bench.
Are there any design principles for reducing the GrovePi’s sensitivity to noise?