I designed a pcb which has two AC channels connected to relays which are eventually controlled by gpios for sure...

the first channel is working great

except for the second channel ... when I set its GPIO hight it works for about 0.5 to 1 second then it turns back off ...

The gpio it self goes of ... I am trying this by terminal not using python or anything..

sudo gpio -g mode 04 out
sudo gpio -g write 04 1
// Now gpio works for 1 second and then goes back to DOWN state

Any ideas why this is happening ??

  • 1
    How exactly are you driving the relays? Is there sufficient current to run both at the same time? Does it happen only when both are on? – Steve Robillard May 27 '17 at 9:40

I am assuming the command you issue is intended to set GPIO 4.

The most likely explanation is you have the 1-wire bus enabled. By default the 1-wire bus is implemented on GPIO 4 and checks devices every few seconds. That will change the GPIO back to being an INPUT.

Either disable the 1-wire bus by removing or commenting out the dtoverlay=w1-gpio,gpiopin=4 entry from /boot/config.txt or change the GPIO it uses.

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