RPICT and MQTT

There are two ways to setup MQTT.
1/ Running a python script.
2/ Using Emonhub.

Using Python Script

In this setup the Raspberrypi where the RPICT is will be the MQTT broker. A script will run to convert the serial string from the RPICT into channel feed.

Setup Mosquito broker

Install Mosquitto using the commands below:

sudo apt install -y mosquitto mosquitto-clients

Enable the service to start at boot time:

sudo systemctl enable mosquitto.service

Make the script

A simple python script can be edited. Create a file with the content of the script below:

MQTT_SERV = "localhost"
MQTT_PATH = "RPICT7V1"
MQTT_USER = "emonpi"
MQTT_PASS = "emonpimqtt2016"

CHANNELS = ["NodeID", "RP1", "RP2", "RP3", "RP4", "RP5", "RP6", "RP7",
		"Irms1", "Irms2", "Irms3", "Irms4", "Irms5", "Irms6", "Irms7",
		"Vrms"]

import paho.mqtt.client as mqtt
import serial
ser = serial.Serial('/dev/ttyAMA0', 38400)

client = mqtt.Client("P1")
client.username_pw_set(MQTT_USER, MQTT_PASS)
client.connect(MQTT_SERV)

try:
	while 1:
		# Read one line from the serial buffer

line = ser.readline()

# Remove the trailing carriage return line feed line = line[:-2]

# Create an array of the data Z = line.split(' ')

# Print it for debug print line

# Publish to the MQTT broker

		for i in range(len(Z)):
			client.publish("%s/%s" % (MQTT_PATH, CHANNELS[i]), Z[i]) 

except KeyboardInterrupt:
	client.disconnect()

ser.close()