Raspberry Pi PicoW MQTT-GPIO With Node-RED

README.md

This will require the umqtt.simple library on the PicoW,

You can install this with upip by running:

import upip
upip.install('umqtt.simple')

If you use a public MQTT broker such as test.mosquitto.org you should change the prefix value in line 8 of the micropython from MYNAME to something unique or you may recieve other peoples commands

Also you will need to update the topics in the flow from MYNAME

You will need to enter the WiFi Details for your network in like 12 of the micropython, change YOUR_WIFI_SSID and YOUR_WIFI_PASSWORD to appropriate values

flow.json

[{"id":"a1278c3bb2492ac8","type":"tab","label":"Flow 1","disabled":false,"info":"","env":[]},{"id":"072eb8be8fa5b953","type":"mqtt out","z":"a1278c3bb2492ac8","name":"","topic":"","qos":"","retain":"","respTopic":"","contentType":"","userProps":"","correl":"","expiry":"","broker":"f59f047b7402cb1e","x":710,"y":120,"wires":[]},{"id":"436051cad470a16e","type":"inject","z":"a1278c3bb2492ac8","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"MYNAME/GPIO/15","payload":"1","payloadType":"num","x":180,"y":140,"wires":[["072eb8be8fa5b953"]]},{"id":"91d674ba9493c9cb","type":"mqtt in","z":"a1278c3bb2492ac8","name":"","topic":"MYNAME/pico","qos":"2","datatype":"auto","broker":"f59f047b7402cb1e","nl":false,"rap":true,"rh":0,"inputs":0,"x":120,"y":300,"wires":[["330a1ccd80e08cdc"]]},{"id":"330a1ccd80e08cdc","type":"debug","z":"a1278c3bb2492ac8","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","x":330,"y":300,"wires":[]},{"id":"92c6361a251d3684","type":"inject","z":"a1278c3bb2492ac8","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"MYNAME/GPIO/15","payload":"0","payloadType":"num","x":180,"y":180,"wires":[["072eb8be8fa5b953"]]},{"id":"c3f373ccb42e5d2c","type":"inject","z":"a1278c3bb2492ac8","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"MYNAME/GPIO/20","payload":"1","payloadType":"num","x":180,"y":60,"wires":[["072eb8be8fa5b953"]]},{"id":"b5a434643a3e22fb","type":"inject","z":"a1278c3bb2492ac8","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"MYNAME/GPIO/20","payload":"0","payloadType":"num","x":180,"y":100,"wires":[["072eb8be8fa5b953"]]},{"id":"f59f047b7402cb1e","type":"mqtt-broker","name":"","broker":"test.mosquitto.org","port":"1883","clientid":"","autoConnect":true,"usetls":false,"protocolVersion":"4","keepalive":"60","cleansession":true,"birthTopic":"","birthQos":"0","birthPayload":"","birthMsg":{},"closeTopic":"","closeQos":"0","closePayload":"","closeMsg":{},"willTopic":"","willQos":"0","willPayload":"","willMsg":{},"sessionExpiry":""}]

gpio-mqtt-keepalive.py

import network
import time
from machine import Pin
from umqtt.simple import MQTTClient

prefix = "MYNAME/"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect('YOUR_WIFI_SSID', 'YOUR_WIFI_PASSWORD')
while not wlan.isconnected() and wlan.status() >= 0:
	print("Waiting to connect:")
	time.sleep(1)


def callback(topic, msg):
    t = topic.decode("utf-8").lstrip(prefix)
    print(t)
    if t[:5] == 'GPIO/':
        p = int(t[5:])
        data = int(msg)
        led = Pin(p, Pin.OUT)
        led.value(data)
        client.publish(prefix+'pico', str(p)+"-"+str(data))

def heartbeat(first):
    global lastping
    if first:
        client.ping()
        lastping = time.ticks_ms()
    if time.ticks_diff(time.ticks_ms(), lastping) >= 300000:
        client.ping()
        lastping = time.ticks_ms()
    return

client = MQTTClient(prefix+"picow", "test.mosquitto.org",user=None, password=None, keepalive=300, ssl=False, ssl_params={})
client.connect()
heartbeat(True)
client.set_callback(callback)
client.subscribe(prefix+"GPIO/#")
while True:
    client.check_msg()
    heartbeat(False)

gpio-mqtt.py

import network
import time
from machine import Pin
from umqtt.simple import MQTTClient

prefix = "MYNAME/"

wlan = network.WLAN(network.STA_IF)
wlan.active(True)
wlan.connect('YOUR_WIFI_SSID', 'YOUR_WIFI_PASSWORD')
while not wlan.isconnected() and wlan.status() >= 0:
	print("Waiting to connect:")
	time.sleep(1)


def callback(topic, msg):
    t = topic.decode("utf-8").lstrip(prefix)
    print(t)
    if t[:5] == 'GPIO/':
        p = int(t[5:])
        data = int(msg)
        led = Pin(p, Pin.OUT)
        led.value(data)
        client.publish(prefix+'pico', str(p)+"-"+str(data))
    
client = MQTTClient(prefix+"picow", "test.mosquitto.org",user=None, password=None, keepalive=300, ssl=False, ssl_params={})
client.connect()
client.set_callback(callback)
client.subscribe(prefix+"GPIO/#")
while True:
    client.wait_msg()

Spotted a tiny typo in the read-me, like/line.