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()

@ratarchivos using MQTT probabbly isn't the best solution there then, look at something simpler like websockets

Can you provide a simple example sending and/or receiving with an external client? Maybe using paho-mqtt

Can you provide a simple example sending and/or receiving with an external client? Maybe using paho-mqtt

Node-RED is an external MQTT client, but if you want to know the topics and payloads that you need to publish the topic is MYNAME/GPIO/[PIN] where [PIN] is the GPIO pin number and then the payload is simply a 1 or 0 to turn the pin on or off

Thanks @sammachin. I need something that I can control programmatically (closed-loop optimization), and I wasn't sure if Node-RED was the way to go for that. I came up with a solution based on this gist in public_mqtt_sdl_demo with a notebook showing the external client sending commands and receiving data in 4.0-paho-mqtt-colab-sdl-demo.ipynb.

Do you know if Node-RED would be amenable to running things in a closed loop, preferably some Python API, or is the way I approached it above more like what you'd recommend?

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