RPi.GPIO for LED, Push Button, Relay Module

rern

RPi.GPIO for LED, Push Button, Relay Module
(Tested on RPi 3)

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updated 20170108 - Python, GCC and RPi.GPIO already installed by default. Installation part removed.

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Symlink Python

ln -s /usr/bin/python2.7 /usr/bin/python

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RPi.GPIO Test

connect 'LED':

[pin 39] --- [jumper] --- [-LED+] --- [jumper] --- [R100ohm] --- [jumper] --- [pin 40]

# python

>>> import RPi.GPIO as GPIO
>>> GPIO.setmode(GPIO.BOARD)
>>> GPIO.setup(40, GPIO.OUT)
>>> GPIO.output(40, 1)
>>> GPIO.output(40, 0)
>>> GPIO.cleanup()
>>> exit()

GPIO.output(40, 1) = LED on
GPIO.output(40, 0) = LED off

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GPIO - LED on/off

connect 'LED':

[pin 40] --- [jumper] --- [+LED-] --- [jumper] --- [R100ohm] --- [jumper] --- [pin 39]

create python on script:

# nano /root/lon.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO

# connect RPi numbered pin
led = 40

GPIO.setmode(GPIO.BOARD)
GPIO.setup(led, GPIO.OUT, initial=1)

create python off script:

# nano /root/loff.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO
		
# connect pins
led = 40
		
# pins setup
GPIO.setmode(GPIO.BOARD)
GPIO.setup(led, GPIO.OUT)
		
GPIO.output(led, 0)
GPIO.cleanup()

change files permision:

# chmod +x /root/*.py

LED on:

/root/lon.py

LED off:

# /root/loff.py

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GPIO - Push Button + LED

connect 'push button':

[pin 33] --- [jumper] --- [push button] --- [jumper] --- [pin 34]

connect 'LED':

[pin 40] --- [jumper] --- [+LED-] --- [jumper] --- [R100ohm] --- [jumper] --- [pin 39]

create python button script:

# nano /root/lflash.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time

# connect RPi numbered pins and flashing duration
led = 40
button = 33
sec = 0.5

# hide warning
GPIO.setwarnings(0)
# pins setup
GPIO.setmode(GPIO.BOARD)
GPIO.setup(button, GPIO.IN, pull_up_down=GPIO.PUD_UP)
GPIO.setup(led, GPIO.OUT)

# wait for button press
print('Wait for button press...')
GPIO.wait_for_edge(button, GPIO.FALLING)

# led flash 3 times then off
GPIO.output(led, 1)
time.sleep(sec)
GPIO.output(led, 0)
time.sleep(sec)
GPIO.output(led, 1)
time.sleep(sec)
GPIO.output(led, 0)
time.sleep(sec)
GPIO.output(led, 1)
time.sleep(sec)
GPIO.output(led, 0)

# clear settings
GPIO.cleanup()

change file permission:

# chmod +x /root/*.py

Activate:

# /root/lflash.py

LED flash:

press button

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GPIO - Push Button + Command (e.g. shutdown)
(Note: A remote control with XBindKeys should be easier than a push button.)

connect 'push button':

[pin 33] --- [push button] --- [jumper] --- [pin 34]

create python button script:

# nano /root/bshutdown.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO
import os

# hide warning
GPIO.setwarnings(0)

# connect RPi numbered pin
button = 33

# hide warning
GPIO.setwarnings(0)

# pins setup
GPIO.setmode(GPIO.BOARD)
GPIO.setup(button, GPIO.IN, pull_up_down=GPIO.PUD_UP)

# wait for button press
print('Wait for button press...')
GPIO.wait_for_edge(button, GPIO.FALLING)
		
# activate system command
os.system('/var/www/command/rune_shutdown; poweroff')

change file permission:

# chmod +x /root/*.py

Shutdown

# /root/bshutdown.py

press button

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GPIO - Relay Module

connect 'relay module' (some pins may glow module LEDs by default)

[pin 6] --- [jumper] --- [module GND]
[pin 35] --- [jumper] --- [module IN1]
[pin 36] --- [jumper] --- [module IN2]
[pin 37] --- [jumper] --- [module IN3]
[pin 38] --- [jumper] --- [module IN4]
[pin 4] --- [jumper] --- [module VCC]

create python relay-on script:

# nano /root/ron.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time

# custom variables
# connected RPi numbered pins
r1 = 35
r2 = 36
r3 = 37
r4 = 38
# delay in seconds
r1delay = 3
r2delay = 1
r3delay = 2
r4delay = 3
		
on = 0
off = 1

# hide warning
GPIO.setwarnings(0)

# pins setup
GPIO.setmode(GPIO.BOARD)

# set pin to output
GPIO.setup([r1,r2,r3,r4], GPIO.OUT, initial=off)

# activate on sequence
if GPIO.input(r1) == on:
	print('Already ON')
else:
	print ('Activate ON sequence in %d s' % r1delay)
	time.sleep(r1delay)
	GPIO.output(r1, on)
	print ('#1 on - wait %d s' % r2delay)
	time.sleep(r2delay)
	GPIO.output(r2, on)
	print ('#2 on - wait %d s' % r3delay)
	time.sleep(r3delay)
	GPIO.output(r3, on)
	print ('#3 on - wait %d s' % r4delay)
	time.sleep(r4delay)
	GPIO.output(r4, on)
	print ('#4 on')
	print ('OFF: roff.py')

create python relay-off script:

# nano /root/roff.py

add to the script:

#!/usr/bin/python
import RPi.GPIO as GPIO
import time

# custom variables
# connected RPi numbered pins
r1 = 35
r2 = 36
r3 = 37
r4 = 38
# delay in seconds
r1delay = 3
r2delay = 1
r3delay = 2
r4delay = 3
	
on = 0
off = 1

# hide warning
GPIO.setwarnings(0)

# pins setup
GPIO.setmode(GPIO.BOARD)

# set pin to output
GPIO.setup([r1,r2,r3,r4], GPIO.OUT)

# activate off sequence
if GPIO.input(r1) == off:
	print('Already OFF')
else:
	print ('Activate OFF sequence in %d s' % r1delay)
	time.sleep(r1delay)
	GPIO.output(r1, off)
	print ('#1 off  - wait %d s' % r2delay)
	time.sleep(r2delay)
	GPIO.output(r2, off)
	print ('#2 off - wait %d s' % r3delay)
	time.sleep(r3delay)
	GPIO.output(r3, off)
	print ('#3 off - wait %d s' % r4delay)
	time.sleep(r4delay)
	GPIO.output(r4, off)
	print ('#4 off')

# clear settings
GPIO.cleanup()

change file permission:

# chmod +x /root/*.py

relays on:

# /root/ron.py

relays off:

# /root/roff.py

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GPIO - Run Script Startup

create systemd service file:

# nano /lib/systemd/system/bshutdown.service

add to the file:

[Unit]
Description = GPIO shutdown button

[Service]
Type = idle
ExecStart = /root/bshutdown.py

[Install]
WantedBy = multi-user.target

enable the service:

# systemctl enable bshutdown

start the service:

# systemctl start bshutdown

dunghnguyen

Thanks @[deleted] for the tutorial. I can learn a bit from this. Let me to see if I can manage time to create some scripts running on Rpi0 to control RPi2 / Rune [WINKING FACE]

I hope even I can create the RPi that it controls itself when pressing the button [emoji1]. In this case, can you advise if we can use another pin for pin 40 instead since we often pin 40 as the DAT of i2s connection to external DAC?

rern

Of course you can use any pin+ground pairs except 3.3V and 5V power supply pins.

dunghnguyen

rern wroteOf course you can use any pin+ground pairs except 3.3V and 5V power supply pins.

Tks for your advice. I read about GPIO recently so if I am not wrong the exception is also pins 27 and 28 as they are for a specific purpose?