gigawatts / SerialMQTTGateway

Script to transfer Serial to MQTT and vice-versa

SerialMQTTGateway Script

Python program to convert serial traffic to MQTT and vice versa.

Serial data arrives as comma delimited in the following form (comma delimited, colons separate MQTT topic and message):

{sending_node_number},{topic}:{message},{topic}:{message}

example:

5,Temperature:20.6,Battery:LOW

using the topic and message from the serial read, the MQTT topics are updated:

sensors/</[sending_node_number]/{topic} {message}

example from above:

Topic: sensors/</5/Temperature Message: 20.6
Topic: sensors/</5/Battery     Message: LOW

MQTT topic sensors/>/# is subscribed to. MQTT Topics should be:

sensors/>/{nodeid} {message}
  or
sensors/>/{nodeid}/{topic} {message}

Any new data is sent to serial as:

<{nodeid}:{topic}:{message}>

eg Topic: sensors/>/5/LED Message:ON or Topic: sensors/>/5 Message:LED:ON would be sent to serial as:

<5:LED:ON>

Which the attached arduino broadcasts over the wireless network. The code in the arduino should look for the start marker "<" and the end marker ">". Any message destined for node 1 (the gateway ardunio) is written to serial without sending node.

Developed for use with Moteinos https://lowpowerlab.com/guide/moteino/ using a modified gateway sketch (to format serial data as comma delimited).

Primary functionality from Python MQTT client from Eclipse Paho http://www.eclipse.org/paho/

Paho documentation at https://pypi.python.org/pypi/paho-mqtt/1.1