View source for RPICT and MQTT



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

=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==

First of all install the mqtt python module
 sudo pip install paho-mqtt

<small>If not installed already install pip first with sudo apt-get install python-pip</small>

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 = ""
 MQTT_PASS = ""
 
 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()

Modify the five parameters '''MQTT_SERV''', '''MQTT_PATH''', '''MQTT_USER''', '''MQTT_PASS''' and '''CHANNELS''' to your needs. We are using a default RPICT7V1 for our example here.

Save the file and launch it with the command
 python myfile.py

When running the above script all channels will be published as soon as data are sent by the RPICT board.

==Test it==

Test the channels by subscribing to one channel as below:
 mosquitto_sub -h localhost -t RPICT7V1/Vrms -u "" -P ""

The value of Vrms will be printed on the terminal.

=Using Emonhub=

If the Emoncms image is used then MQTT is already setup. Simply use Emonhub.

Include the following config in the emonhub config.

 <nowiki>[[MQTT]]</nowiki>
     Type = EmonHubMqttInterfacer
     [[[init_settings]]]
         mqtt_host = 127.0.0.1
         mqtt_port = 1883
         mqtt_user = 'emonpi'
         mqtt_passwd = 'emonpimqtt2016'
 
     [[[runtimesettings]]]
         pubchannels = ToRFM12,
         subchannels = ToEmonCMS,
 
         # emonhub/rx/10/values format
         # Use with emoncms Nodes module
         node_format_enable = 1
         node_format_basetopic = emonhub/
 
         # emon/emontx/power1 format - use with Emoncms MQTT input
         # http://github.com/emoncms/emoncms/blob/master/docs/RaspberryPi/MQTT.md
         nodevar_format_enable = 1
         nodevar_format_basetopic = emon/

Make sure the config also include the sensor config for the RPICT. For our RPICT7V1 example this is:

  <nowiki>[[11]]</nowiki>
    nodename = my_RPICT7V1
    hardware = RPICT7V1
    [[[rx]]]
       names = RP1, RP2, RP3, RP4, RP5, RP6, RP7, Irms1, Irms2, Irms3, Irms4, Irms5, Irms6, Irms7, Vrms
       datacode = 0
       scales = 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
       units =W,W,W,W,W,W,W,mA,mA,mA,mA,mA,mA,mA,V

Test the final setup using the command below:
 mosquitto_sub -h localhost -t emon/my_RPICT7V1/Vrms -u emonpi -P emonpimqtt2016