Remote GPIO with GPIO Zero, pigpio and the Traffic HAT Ben Nuttall Raspberry Pi Foundation UK Charity 1129409 

Open Thonny Python IDE 

Type into the shell 

>>> from gpiozero import * >>> th = TrafficHat() >>> th.lights.on() >>> th.lights.blink() >>> th.buzzer.on() >>> th.buzzer.off() >>> th.button.when_pressed = th.on >>> th.button.when_released = th.off 

Source/values >>> th.lights.green.value False >>> th.button.value False >>> th.button.value True >>> th.lights.green.source = th.button.values 

GPIO Zero pin factories ● GPIO Zero allows use with various pin libraries: – RPi.GPIO (default) – RPIO – pigpio – Native – Mock ● You can select one to use at launch ● Or you can change on the fly! 

pigpio ● Pin library implemented in C ● Runs as a daemon as root ● You can communicate to it with sockets (without root) ● Lots of advanced GPIO features built-in ● Accepts socket requests over the network, allowing remote GPIO capabilities ● Remote GPIO works between two Pis, or from PC to Pi 

Close Thonny and open a Terminal 

Start the pigpio daemon $ sudo pigpiod 

Find your IP address $ hostname -I 

Launch Thonny with another Pi’s IP address $ GPIOZERO_PIN_FACTORY=pigpio PIGPIO_ADDR=10.3.12.117 thonny& 

Connect to the remote Traffic HAT >>> from gpiozero import * >>> th = TrafficHat() >>> th.pin_factory >>> th.lights.blink() 

Examples! 

AND logic gate # launch with remote Pi’s IP address as default pin factory from gpiozero import Button, LED from gpiozero.pins.rpigpio import RPiGPIOFactory from gpiozero.tools import all_values local = RPiGPIOFactory() other_led = LED(22) # remote other_btn = Button(25) # remote my_btn = Button(25, pin_factory=local) # local other_led.source = all_values(my_btn.values, other_btn.values) 

OR logic gate # launch with remote Pi’s IP address as default pin factory from gpiozero import Button, LED from gpiozero.pins.rpigpio import RPiGPIOFactory from gpiozero.tools import any_values local = RPiGPIOFactory() other_led = LED(22) # remote other_btn = Button(25) # remote my_btn = Button(25, pin_factory=local) # local other_led.source = any_values(my_btn.values, other_btn.values) 

PingServer from gpiozero import TrafficHat, PingServer from gpiozero.tools import negated th = TrafficHat() ps = PingServer(‘10.3.15.15’) th.lights.green.source = ps.values th.lights.red.source = negated(ps.values) 

CPUTemperature from gpiozero import LEDBarGraph, CPUTemperature leds = LEDBarGraph(22, 23, 24, pwm=True) cpu = CPUTemperature(min_temp=40, max_temp=70) print(cpu.temperature) leds.source = cpu.values 

CPUTemperature buzzer from gpiozero import PWMOutputDevice, CPUTemperature buzzer = PWMOutputDevice(5) cpu = CPUTemperature(min_temp=40, max_temp=70) print(cpu.temperature) buzzer.source = cpu.values 

Multi-room motion alert from gpiozero import LEDBoard, MotionSensor from gpiozero.pins.pigpio import PiGPIOFactory from signal import pause ips = ['192.168.1.3', '192.168.1.4', '192.168.1.5', '192.168.1.6'] remotes = [PiGPIOFactory(host=ip) for ip in ips] leds = LEDBoard(2, 3, 4, 5) # leds on this pi sensors = [MotionSensor(17, pin_factory=r) for r in remotes] # remote sensors for led, sensor in zip(leds, sensors): led.source = sensor.values pause() 

Multi-room doorbell from gpiozero import LEDBoard, MotionSensor from gpiozero.pins.pigpio import PiGPIOFactory from signal import pause ips = ['192.168.1.3', '192.168.1.4', '192.168.1.5', '192.168.1.6'] remotes = [PiGPIOFactory(host=ip) for ip in ips] button = Button(17) # button on this pi buzzers = [Buzzer(pin, pin_factory=r) for r in remotes] # buzzers on remote pins for buzzer in buzzers: buzzer.source = button.values pause() 

Sense HAT from gpiozero import LightSensor from gpiozero.pins.pigpio import PiGPIOFactory from sense_hat import SenseHat factory = PiGPIOFactory(host='192.168.1.4') light = LightSensor(4, pin_factory=factory)) # remote motion sensor sense = SenseHat() # local sense hat blue = (0, 0, 255) yellow = (255, 255, 0) while True: if light.value > 0.5: sense.clear(yellow) else: sense.clear(blue) 

Remote button robot from gpiozero import Button, Robot from gpiozero.pins.pigpio import PiGPIOFactory factory = PiGPIOFactory(host='192.168.1.17') robot = Robot(left=(4, 14), right=(17, 18), pin_factory=factory) # remote pins # local buttons left = Button(26) right = Button(16) fw = Button(21) bw = Button(20) fw.when_pressed = robot.forward fw.when_released = robot.stop left.when_pressed = robot.left left.when_released = robot.stop right.when_pressed = robot.right right.when_released = robot.stop bw.when_pressed = robot.backward bw.when_released = robot.stop 

Remote pot robot from gpiozero import Robot, MCP3008 robot = Robot(left=(4, 14), right=(17, 18)) left = MCP3008(0) right = MCP3008(1) robot.source = zip(left.values, right.values) 

Remote pot robot from gpiozero import Robot, MCP3008 from gpiozero.tools import scaled robot = Robot(left=(4, 14), right=(17, 18)) left = MCP3008(0) right = MCP3008(1) robot.source = zip(scaled(left.values, -1, 1), scaled(right.values, -1, 1)) 

What can you control remotely? ● Pi with LEDs showing who is home (ping known mobile phone IP addresses) ● Pi with LEDs showing sensor data from other rooms ● Pi with LEDs showing data from the internet (e.g. tube line info) ● Control robot remotely from your PC ● Use two HATs at once ● Run the same script on multiple Pis from one control PC