The project itself is very simple: getting push notifications via MQTT when a wireless doorbell sounds. But as [Robin Reiter] points out, as the “Hello, world!” program is a time-honored tradition for coders new to a language, so too is his project very much the hardware embodiment of the same tradition. And the accompanying video build log below is a whirlwind tour that will get the first-timer off the ground and on the way to MQTT glory.
The hardware [Robin] chose for this primer is pretty basic – a wireless doorbell consisting of a battery-powered button and a plug-in receiver that tootles melodiously when you’ve got a visitor. [Robin] engages in a teardown of the receiver with attempted reverse engineering, but he wisely chose the path of least resistance and settled on monitoring the LEDs that flash when the button is pushed. An RFduino was selected from [Robin]’s ridiculously well-organized parts bin and wired up for the job. The ‘duino-fied doorbell talks Bluetooth to an MQTT broker on a Raspberry Pi, which also handles push notifications to his phone.
The meat of the build log, though, is the details of setting up MQTT. We’ve posted a lot about MQTT, including [Elliot Williams]’ great series on the subject. But this tutorial is very nuts and bolts, the kind of thing you can just follow along with, pause the video once in a while, and have a working system up and running quickly. There’s a lot here for the beginner, and even the old hands will pick up a tip or two.