MQTT for ScratchGPIO

I’ve been playing with using MQTT to send messages between computers around the house and I’ve now built in the capability of using it in ScratchGPIO for the Raspberry Pi

Setting Up

You have to install MQTT python support before launching ScratchGPIO

Launch a Terminal window and enter

sudo pip install paho-mqtt

Once installed you can close the terminal window and launch ScratchGPIO

Simply create a variable called MQTTBroker and enter the name of the broker you want to use.

e.g set MQTTBroker to

or in my case

set MQTTBroker to win8.local (my own broker running 24/7 on main windows PC)

Then setup one Pi to receive msgs

broadcast MQTTSubscribe topic

and then on the sending Pi

broadcast SendMQTT topic,payload

You should now see a sensor variable on the receiving Pi called topic and its value should be payload

If you simply want to just test getting some external test data into you Pi – I recommend just doing the script on the left and then displaying the current cheerlights sensor value.

Then tweet a colour to @cheerlights

e.g. @cheerlights red

and watch the sensor value update within a minute