Provided by: python3-gpiozero_1.6.1-0ubuntu1_all 
NAME
remote-gpio - GPIO Zero remote GPIO guide
GPIO Zero supports a number of different pin implementations (low-level pin libraries
which deal with the GPIO pins directly). By default, the RPi.GPIO
<https://pypi.python.org/pypi/RPi.GPIO> library is used (assuming it is installed on your
system), but you can optionally specify one to use. For more information, see the api_pins
documentation page.
One of the pin libraries supported, pigpio <http://abyz.me.uk/rpi/pigpio/python.html>,
provides the ability to control GPIO pins remotely over the network, which means you can
use GPIO Zero to control devices connected to a Raspberry Pi on the network. You can do
this from another Raspberry Pi, or even from a PC.
See the recipes_remote_gpio page for examples on how remote pins can be used.
PREPARING THE RASPBERRY PI
If you're using Raspberry Pi OS (desktop - not Lite) then you have everything you need to
use the remote GPIO feature. If you're using Raspberry Pi OS Lite, or another
distribution, you'll need to install pigpio:
$ sudo apt install pigpio
Alternatively, pigpio is available from abyz.me.uk
<http://abyz.me.uk/rpi/pigpio/download.html>.
You'll need to enable remote connections, and launch the pigpio daemon on the Raspberry
Pi.
Enable remote connections
On the Raspberry Pi OS desktop image, you can enable Remote GPIO in the Raspberry Pi
configuration tool: [image]
Alternatively, enter sudo raspi-config on the command line, and enable Remote GPIO. This
is functionally equivalent to the desktop method.
This will allow remote connections (until disabled) when the pigpio daemon is launched
using systemctl (see below). It will also launch the pigpio daemon for the current
session. Therefore, nothing further is required for the current session, but after a
reboot, a systemctl command will be required.
Command-line: systemctl
To automate running the daemon at boot time, run:
$ sudo systemctl enable pigpiod
To run the daemon once using systemctl, run:
$ sudo systemctl start pigpiod
Command-line: pigpiod
Another option is to launch the pigpio daemon manually:
$ sudo pigpiod
This is for single-session-use and will not persist after a reboot. However, this method
can be used to allow connections from a specific IP address, using the -n flag. For
example:
$ sudo pigpiod -n localhost # allow localhost only
$ sudo pigpiod -n 192.168.1.65 # allow 192.168.1.65 only
$ sudo pigpiod -n localhost -n 192.168.1.65 # allow localhost and 192.168.1.65 only
NOTE:
Note that running sudo pigpiod will not honour the Remote GPIO configuration setting
(i.e. without the -n flag it will allow remote connections even if the remote setting
is disabled), but sudo systemctl enable pigpiod or sudo systemctl start pigpiod will
not allow remote connections unless configured accordingly.
PREPARING THE CONTROL COMPUTER
If the control computer (the computer you're running your Python code from) is a Raspberry
Pi running Raspberry Pi OS (or a PC running Raspberry Pi Desktop x86
<https://www.raspberrypi.org/downloads/raspberry-pi-desktop/>), then you have everything
you need. If you're using another Linux distribution, Mac OS or Windows then you'll need
to install the pigpio <http://abyz.me.uk/rpi/pigpio/python.html> Python library on the PC.
Raspberry Pi
First, update your repositories list:
$ sudo apt update
Then install GPIO Zero and the pigpio library for Python 3:
$ sudo apt install python3-gpiozero python3-pigpio
or Python 2:
$ sudo apt install python-gpiozero python-pigpio
Alternatively, install with pip:
$ sudo pip3 install gpiozero pigpio
or for Python 2:
$ sudo pip install gpiozero pigpio
Linux
First, update your distribution's repositories list. For example:
$ sudo apt update
Then install pip for Python 3:
$ sudo apt install python3-pip
or Python 2:
$ sudo apt install python-pip
(Alternatively, install pip with get-pip <https://pip.pypa.io/en/stable/installing/>.)
Next, install GPIO Zero and pigpio for Python 3:
$ sudo pip3 install gpiozero pigpio
or Python 2:
$ sudo pip install gpiozero pigpio
Mac OS
First, install pip. If you installed Python 3 using brew, you will already have pip. If
not, install pip with get-pip <https://pip.pypa.io/en/stable/installing/>.
Next, install GPIO Zero and pigpio with pip:
$ pip3 install gpiozero pigpio
Or for Python 2:
$ pip install gpiozero pigpio
Windows
Modern Python installers for Windows bundle pip with Python. If pip is not installed, you
can follow this guide <https://projects.raspberrypi.org/en/projects/using-pip-on-windows>.
Next, install GPIO Zero and pigpio with pip:
C:\Users\user1> pip install gpiozero pigpio
ENVIRONMENT VARIABLES
The simplest way to use devices with remote pins is to set the PIGPIO_ADDR environment
variable to the IP address of the desired Raspberry Pi. You must run your Python script or
launch your development environment with the environment variable set using the command
line. For example, one of the following:
$ PIGPIO_ADDR=192.168.1.3 python3 hello.py
$ PIGPIO_ADDR=192.168.1.3 python3
$ PIGPIO_ADDR=192.168.1.3 ipython3
$ PIGPIO_ADDR=192.168.1.3 idle3 &
If you are running this from a PC (not a Raspberry Pi) with gpiozero and the pigpio
<http://abyz.me.uk/rpi/pigpio/python.html> Python library installed, this will work with
no further configuration. However, if you are running this from a Raspberry Pi, you will
also need to ensure the default pin factory is set to PiGPIOFactory. If RPi.GPIO
<https://pypi.python.org/pypi/RPi.GPIO> is installed, this will be selected as the default
pin factory, so either uninstall it, or use the GPIOZERO_PIN_FACTORY environment variable
to override it:
$ GPIOZERO_PIN_FACTORY=pigpio PIGPIO_ADDR=192.168.1.3 python3 hello.py
This usage will set the pin factory to PiGPIOFactory with a default host of 192.168.1.3.
The pin factory can be changed inline in the code, as seen in the following sections.
With this usage, you can write gpiozero code like you would on a Raspberry Pi, with no
modifications needed. For example:
from gpiozero import LED
from time import sleep
red = LED(17)
while True:
red.on()
sleep(1)
red.off()
sleep(1)
When run with:
$ PIGPIO_ADDR=192.168.1.3 python3 led.py
will flash the LED connected to pin 17 of the Raspberry Pi with the IP address
192.168.1.3. And:
$ PIGPIO_ADDR=192.168.1.4 python3 led.py
will flash the LED connected to pin 17 of the Raspberry Pi with the IP address
192.168.1.4, without any code changes, as long as the Raspberry Pi has the pigpio daemon
running.
NOTE:
When running code directly on a Raspberry Pi, any pin factory can be used (assuming the
relevant library is installed), but when a device is used remotely, only PiGPIOFactory
can be used, as pigpio <http://abyz.me.uk/rpi/pigpio/python.html> is the only pin
library which supports remote GPIO.
PIN FACTORIES
An alternative (or additional) method of configuring gpiozero objects to use remote pins
is to create instances of PiGPIOFactory objects, and use them when instantiating device
objects. For example, with no environment variables set:
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
factory = PiGPIOFactory(host='192.168.1.3')
led = LED(17, pin_factory=factory)
while True:
led.on()
sleep(1)
led.off()
sleep(1)
This allows devices on multiple Raspberry Pis to be used in the same script:
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
factory3 = PiGPIOFactory(host='192.168.1.3')
factory4 = PiGPIOFactory(host='192.168.1.4')
led_1 = LED(17, pin_factory=factory3)
led_2 = LED(17, pin_factory=factory4)
while True:
led_1.on()
led_2.off()
sleep(1)
led_1.off()
led_2.on()
sleep(1)
You can, of course, continue to create gpiozero device objects as normal, and create
others using remote pins. For example, if run on a Raspberry Pi, the following script will
flash an LED on the controller Pi, and also on another Pi on the network:
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
remote_factory = PiGPIOFactory(host='192.168.1.3')
led_1 = LED(17) # local pin
led_2 = LED(17, pin_factory=remote_factory) # remote pin
while True:
led_1.on()
led_2.off()
sleep(1)
led_1.off()
led_2.on()
sleep(1)
Alternatively, when run with the environment variables GPIOZERO_PIN_FACTORY=pigpio
PIGPIO_ADDR=192.168.1.3 set, the following script will behave exactly the same as the
previous one:
from gpiozero import LED
from gpiozero.pins.rpigpio import RPiGPIOFactory
from time import sleep
local_factory = RPiGPIOFactory()
led_1 = LED(17, pin_factory=local_factory) # local pin
led_2 = LED(17) # remote pin
while True:
led_1.on()
led_2.off()
sleep(1)
led_1.off()
led_2.on()
sleep(1)
Of course, multiple IP addresses can be used:
from gpiozero import LED
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
factory3 = PiGPIOFactory(host='192.168.1.3')
factory4 = PiGPIOFactory(host='192.168.1.4')
led_1 = LED(17) # local pin
led_2 = LED(17, pin_factory=factory3) # remote pin on one pi
led_3 = LED(17, pin_factory=factory4) # remote pin on another pi
while True:
led_1.on()
led_2.off()
led_3.on()
sleep(1)
led_1.off()
led_2.on()
led_3.off()
sleep(1)
Note that these examples use the LED class, which takes a pin argument to initialise. Some
classes, particularly those representing HATs and other add-on boards, do not require
their pin numbers to be specified. However, it is still possible to use remote pins with
these devices, either using environment variables, or the pin_factory keyword argument:
import gpiozero
from gpiozero import TrafficHat
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
gpiozero.Device.pin_factory = PiGPIOFactory(host='192.168.1.3')
th = TrafficHat() # traffic hat on 192.168.1.3 using remote pins
This also allows you to swap between two IP addresses and create instances of multiple
HATs connected to different Pis:
import gpiozero
from gpiozero import TrafficHat
from gpiozero.pins.pigpio import PiGPIOFactory
from time import sleep
remote_factory = PiGPIOFactory(host='192.168.1.3')
th_1 = TrafficHat() # traffic hat using local pins
th_2 = TrafficHat(pin_factory=remote_factory) # traffic hat on 192.168.1.3 using remote pins
You could even use a HAT which is not supported by GPIO Zero (such as the Sense HAT
<https://www.raspberrypi.org/products/sense-hat/>) on one Pi, and use remote pins to
control another over the network:
from gpiozero import MotionSensor
from gpiozero.pins.pigpio import PiGPIOFactory
from sense_hat import SenseHat
remote_factory = PiGPIOFactory(host='192.198.1.4')
pir = MotionSensor(4, pin_factory=remote_factory) # remote motion sensor
sense = SenseHat() # local sense hat
while True:
pir.wait_for_motion()
sense.show_message(sense.temperature)
Note that in this case, the Sense HAT code must be run locally, and the GPIO remotely.
REMOTE GPIO USAGE
Continue to:
• recipes_remote_gpio
• pi_zero_otg
AUTHOR
Ben Nuttall
COPYRIGHT
2015-2021 Ben Nuttall