remote-gpio - GPIO Zero remote GPIO guide

Ben Nuttall

2015-2024 Ben Nuttall 2.0.1 Feb 15, 2024 REMOTE-GPIO(7)

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.

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 RemoteGPIORecipes page for examples on how remote pins can be used.

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=pigpioPIGPIO_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 SenseHAT <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.

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 RaspberryPiDesktopx86 <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. RaspberryPi 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 MacOS 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 followthisguide <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

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. Enableremoteconnections On the Raspberry Pi OS desktop image, you can enable RemoteGPIO in the Raspberry Pi configuration tool: [image] Alternatively, enter sudoraspi-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 sudopigpiod 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 sudosystemctlenablepigpiod or sudosystemctlstartpigpiod will not allow remote connections unless configured accordingly.

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