MQTT with NRF24
In this page, I suppose:
- 10 sensors send their data (temperature, humidity and brightness) via their NRF24 antennas
- One NRF24 is plugged into the USB port of a Raspberry and receives the values
- The values are then sent to Home Asssitant via MQTT.
Read data from serial port
Find Serial port
The message that arrives on USB port is similar to:b'23;3;172;460;235\n
We read the input on the USB port with the following code:
my_serial.py
import serial
#Serial takes these two parameters: serial device and baudrate
ser = serial.Serial('/dev/ttyUSB0', 9600)
while True:
data = ser.readline()
d=data.decode()
dd = d.rstrip("\n")
ddd=dd.split(';')
count = ddd[0]
id = ddd[1]
temp = str(float(ddd[2]) / 10)
lumi = str(float(ddd[3]) / 10)
humi = ddd[4]
print(f"\ncount `{count}`")
print(f"id `{id}`")
print(f"Temp `{temp}°C`")
print(f"Lumi `{lumi}`")
print(f"Humi `{humi}`")
MQTT Submit
First, install MQTT library
Example :
We want to submit json:
#!{"Temperature":11.44751815947774,"Humidite":85.19176787958504"} on topic NRF24/Cuisine
# python 3.6
# See https://www.emqx.com/en/blog/how-to-use-mqtt-in-python
import random
import time
from paho.mqtt import client as mqtt_client
broker = 'homeassistant.local'
port = 1883
client_id = f'NRF24_sensor_2.4_GHz'
username = 'homeassistant'
password = 'weiyai1eFeidaeLithoom6go0OhThooz1IePhaiPh0thae5haephei5siele8aM2'
def connect_mqtt():
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\n", rc)
client = mqtt_client.Client(client_id)
client.username_pw_set(username, password)
client.on_connect = on_connect
client.connect(broker, port)
return client
def publish(client):
while True:
time.sleep(1)
# {"Temperature":11.44751815947774,"Humidite":85.19176787958504"}"
## Cuisine
topic = "NRF24/Cuisine"
temp = random.uniform(10.0, 20.0)
humi = random.uniform(80.0, 99.0)
msg = '{"temperature": ' + str(temp) + ',"humidite": ' + str(humi) + '}'
result = client.publish(topic, msg)
# result: [0, 1]
status = result[0]
if status == 0:
print(f"Send `{msg}` to topic `{topic}`")
else:
print(f"Failed to send message to topic {topic}")
def run():
client = connect_mqtt()
client.loop_start()
publish(client)
if __name__ == '__main__':
run()
See the result with MQTT Explorer
# python 3.6
# See https://www.emqx.com/en/blog/how-to-use-mqtt-in-python
import random
import time
from paho.mqtt import client as mqtt_client
broker = 'homeassistant.local'
port = 1883
# generate client ID with pub prefix randomly
client_id = f'RaspCuisine'
username = 'homeassistant'
password = 'weiyai1eFeidaeLithoom6go0OhThooz1IePhaiPh0thae5haephei5siele8aM2'
def connect_mqtt():
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\n", rc)
client = mqtt_client.Client(client_id)
client.username_pw_set(username, password)
client.on_connect = on_connect
client.connect(broker, port)
return client
def publish(client):
while True:
time.sleep(1)
# {"Temperature":11.44751815947774,"Humidite":85.19176787958504"}"
## Cuisine
topic = "NRF24/Cuisine"
temp = random.uniform(10.0, 20.0)
humi = random.uniform(80.0, 99.0)
msg = '{"temperature": ' + str(temp) + ',"humidite": ' + str(humi) + '}'
result = client.publish(topic, msg)
# result: [0, 1]
status = result[0]
if status == 0:
print(f"Send `{msg}` to topic `{topic}`")
else:
print(f"Failed to send message to topic {topic}")
def run():
client = connect_mqtt()
client.loop_start()
publish(client)
if __name__ == '__main__':
run()
Finaly:
# python 3.6
import random
import time
import serial
ser = serial.Serial('/dev/ttyUSB0', 9600)
from paho.mqtt import client as mqtt_client
broker = 'homeassistant.local'
port = 1883
# generate client ID with pub prefix randomly
client_id = f'RaspCuisine'
username = 'homeassistant'
password = 'weiyai1eFeidaeLithoom6go0OhThooz1IePhaiPh0thae5haephei5siele8aM2'
def connect_mqtt():
def on_connect(client, userdata, flags, rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\n", rc)
client = mqtt_client.Client(client_id)
client.username_pw_set(username, password)
client.on_connect = on_connect
client.connect(broker, port)
return client
def publish(client):
while True:
# Wait for a new line on the serial port
# b'23;3;172;460;235\n'
data = ser.readline()
d=data.decode()
dd = d.rstrip("\n")
ddd=dd.split(';')
# Decrypt received string
count = ddd[0]
id = ddd[1]
temp = str(float(ddd[2]) / 10)
lumi = ddd[3]
humi = str(float(ddd[4]) / 10)
print(f"\ncount `{count}`")
print(f"id `{id}`")
print(f"Temp `{temp}°C`")
print(f"Lumi `{lumi}`")
print(f"Humi `{humi}`")
topic = "NRF24/Unknow Sensor"
# Submit the values to the correct topic
if (id == "13"): # Cuisine
topic = "NRF24/Cuisine_NRF24"
elif (id == "2"): # Bureau
topic = "NRF24/Bureau_NRF24"
elif (id == "3"): # Chambre parents
topic = "NRF24/Chambre_parent_NRF24"
elif (id == "4"): # Chambre parents
topic = "NRF24/Garage_NRF24"
elif (id == "5"): # Exterieur devant maison
topic = "NRF24/Exterieur_NRF24"
elif (id == "11"): # Salle de bain
topic = "NRF24/Salle_de_bain_NRF24"
elif (id == "12"): # Vide sanitaire
topic = "NRF24/Vide_sanitaire_NRF24"
elif (id == "19"): # Chambre Damien
topic = "NRF24/Chambre_Damien_NRF24"
elif (id == "22"): # Chambre Amélie
topic = "NRF24/Chambre_Amelie_NRF24"
else:
print("Unknow id")
msg = '{"temperature": ' + temp + ',"humidite": ' + humi + '}'
print (msg)
result = client.publish(topic, msg)
# result: [0, 1]
status = result[0]
if status == 0:
print(f"Send `{msg}` to topic `{topic}`")
else:
print(f"Failed to send message to topic {topic}")
def run():
client = connect_mqtt()
client.loop_start()
publish(client)
if __name__ == '__main__':
run()
Edit the file /etc/rc.local using the editor of your choice. You must edit it with root permissions:
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