433toMQTTto433 - Bidirectional Arduino gateway between RF 433Mhz signal and MQTT

The goal of the Arduino 433toMQTTto433 is to act as a gateway between 433Mhz sensors and a MQTT broker or between the MQTT broker and 433Mhz actuators, It enables to:

• receive MQTT data from a topic and send RF 433Mhz signal corresponding to the received MQTT data 
• publish MQTT data to a different topic related to received 433Mhz signal 

It can be an interesting part in an home automation system so as to interface sensors and actuators with software like openhab.

The interest of putting this gateway to an arduino and not on a raspberry pi is to be able to manage security actions at arduino level (power on a siren, cut power to certain devices) following RF data received by sensors without being dependent to the PI for security related actions.

[EDIT] all infos are now centralized into the github repository take a look at it you will find up to date info about OpenMQTTGateway

You need:

• Arduino UNO 
• W5100 Ethernet shield 
• 433Mhz Receiver XD RF 5V and transmitter FS1000A 

Transmitter VCC must be plugged to pin 9, signal to pin 10, Receiver signal to pin 2
Here is the schematic:

The transmitter VCC is connected to a signal PIN of the arduino so as to activate it on needs, if it was linked to permanent VCC we would not be able to receive data due tu conflicts between the receiver and the transmitter. That's why we activate the PIN9 on demand when we need to send RF data.

In real life:

Download the following libraries into your arduino environment:

• RCSwitch
• PubSubClient
• Ethernet

Install Mosquitto to your server.

Download the code of the gateway:

The code of the gateway can be found here https://github.com/1technophile/433toMQTTto433

Modify the lines of the sketch so as to make it communicate with your mosquitto server:

1. First line is the MAC adress of the arduino, you can put what you want as long as it respect MAC adress requirement
2. Second line is the IP of your Mosquitto server
3. Third line is the Arduino IP
4. Fourth line set the port used to communicate to Mosquitto 1883 is the default one

	byte mac[] = { 0xDE, 0xED, 0xBA, 0xFE, 0x34, 0x99 };
	byte localserver[] = { 192, 168, 1, 45 };
	byte ip[] = { 192, 168, 1, 23 }; PubSubClient client(localserver, 1883, callback,ethClient);

Upload the sketch to your arduino and open the serial monitor with a speed set to 9600b.

Launch or verify that you mosquitto broker is up and running

If the connexion to mosquitto is ok you should see on the serial monitor of the arduino "connected" & "subscription OK to home/MQTTto433/"

Now you can do some tests to verify that all is working as expected, here is some usefull commands to test gateway with mosquitto from the server, on your mosquitto server:

• Subscribe to the subject for data reiception from RF signal 

mosquitto_sub -t home/433toMQTT

• Send data by MQTT to convert it on RF signal 

mosquitto_pub -t home/MQTTto433/ -m 1315156

Arduino serial data received when publishing data by MQTT

We see that the Arduino receive the value 1315156 on the MQTT subject "MQTTto433" and send the data by RF

Enjoy!