GPIO Status on Boot

[osmosis311]

I have a project I'm working on where I've got a power switch with inputs for a relay controlled by a NodeJS app on my Pi. The relay is triggered by +5V. When my Pi 2 boots, the GPIO's are HIGH, and the relay gets triggered.

Is there any way to get the GPIO pins not to be high when the system boots? How do others get around this issue?

Thanks!

[rpdom]

Which pins are you using?

Most GPIOs are set to input at boot, but some of them have the pull-up resistors set and some have pull-down. You could put in an external pull-down resistor of your own to override the internal one. Something around 4.7K should do it.

(except pins 3 and 5 GPIO 2 and 3, which have strong external pull-up resistors on the board. 1.8K, IIRC)

[gordon77]

Which relay is it and how is it wired ?. Some relay boards are activated by a low.

[faramon]

Is there any way to get the GPIO pins not to be high when the system boots? How do others get around this issue?

I do autostart with python script.

1. Do DESKTOP script (i name it MyPiAutostart.desktop) with this code into it and put this desktop file into /home/pi/.config/autostart folder:
[Desktop Entry]
Type=Application
Name=MyPiAutostart
Exec=sudo python2 /home/pi/myFolder/checkAndSetGPIO.py # with path you have and yours filename
StartupNotify=false

2. Python script checkAndSetGPIO.py contains:
#!/usr/bin/python

import RPi.GPIO as GPIO
import time

pin1 = 17

GPIO.setmode(GPIO.BCM) # choose BCM or BOARD
GPIO.setwarnings(False)

GPIO.setup(pin1, GPIO.OUT) # set a port/pin as an output
GPIO.output(pin1, GPIO.LOW) # set port/pin value to 1/GPIO.HIGH/True in your case
#time.sleep(0.3) # sleep for 'n' seconds

and that is all. Now, on reboot it will check and set pin gpio 17.

Faramon