MQTT
I was originally looking at MQTT right now in the context of Presence Detection. It turned out that Home Assistant already had a good integration with UniFi so I stopped working on that. Now I am building an ESP8266 Arduino (WeMos D1) light strip controller.
My Mosquitto MQTT Server is in a docker container on Bellman. I can log into that container and run commands to learn more.
Listen for presence messages from anyone. QOS is set to 'at least once'. -d is for debug. -t defines what I listen to, where the "+" is a wildcard.
docker exec -it mosquitto mosquitto_sub -t 'sensors/+/presence' -q 1 -d
Send a message.
docker exec -it mosquitto mosquitto_pub -t 'sensors/unifi/presence' -q 1 -d -m 'Julie arrived'
How should my messages look?
- PUB Home Assistant will publish desired LED settings.
- SUB The Arduino will subscribe and adjust the LEDs accordingly.
- PUB After making changes the Arduino will send current settings. On power up the Arduino will restore the last state of the strip and send status.
- SUB Home Assistant will subscribe and display the LED settings.
I should be able to mock both sides with a bit of Python.
Python for testing
conda create --name mqtt conda activate mqtt conda install -c conda-force paho-mqtt
Here's my very first program. It sends a 1 or a 0 to whatever wants to hear it.
import paho.mqtt.publish as publish
import time
HOST = "192.168.123.2"
state = True
target = "blinker"
while(1):
print(state)
publish.single(target, "1" if state else "0", hostname=HOST)
time.sleep(1)
state = not state
Arduino
Now I need to make the WeMos D1 listen and respond. First I tried the Adafruit library and their sample code. It works, but the MQTT server is out there in the cloud and interfaces with a web page at Adafruit. I want to keep a lid on things.
Per the article in the Resources section I am trying PubSubClient which can be installed from the Library Manager in the Arduino IDE.
I wrote my own little MQTT program that just communicated with RGBW numbers, like this: 0100 0100 0300 0400. It worked great and I was able to send commands from the MQTT console in the Developer section of Home Assistant. Then I found this: https://github.com/corbanmailloux/esp-mqtt-rgb-led
I used the name mqtt-hallway and topics state: home/rgbw and command: home/rgbw/set.
Resources
Books - There are some good books in Safari including "Hands-on MQTT Programming With Python".
