Talking MQTT


Ha! Today has been a good day. I’ve got my Air Quality sensor talking MQTT to the Connected Humber server and sending messages. This has been a bit of an adventure, mainly because I had to mess around with the libraries for the Heltec device that I’m using.

Anyhoo, I’m now sending messages over both LoRa and MQTT at the same time. Go me. Now I just need to add some configuration options and I think we might actually have a product here.

Incidentally, I’m using a Windows app called MQTTBox to view the messages on the server and post test messages to my sensor. Works rather nicely. And free.

Air Quality Sensor Version 1.0

If you think that all I've done over the last week is work on my Air Quality sensor you'd be wrong. But I have been quite busy with it. I've now got a proper menu system with messages and numeric input. Plus a box. The box has been particularly fun to design, especially as the Heltec micro controller, in common with lots of similar devices, doesn't seem to provide any way that it can be fitted into a case. I've ended up making a little clamp that holds it in position. I'm not happy with this, but then again I'm not crazy about my looks either - but what are you going to do? 

To say that the case is printed version 1.0 it has gone together quite well. I'm using the "dead cockroach" assembly technique, where you regard the chip as a dead cockroach lying on its back and connect the wires to the upturned legs. There are no components other than the devices that I'm wiring together. The only tricky bit is that the clock and the temperature sensor share the same SDA and SCL lines and so I've had to make up some custom cables. But it's all working, and now I have a box with all my sensors and whatnot that I can start to to build software for. 


This is the ugly truth about what's in the box. We'll gloss over the way that the wires for the RTC are too short to allow it to be fitted onto its mounting post, and the wire for the sensor is far too long......

The next step is to add a "WiFi Setup" mode that can be used to get the device onto the internet and then we can start pushing readings into the cloud. You can track the project on GitHub here. Bear in mind that this is a work in progress, and so nothing is fixed. This is all part of the Connected Humber Monitaire project, you can find out more here