Defsystem Sensor Systems and Home Assistant
Home Assistant
can be used as a backend for our sensor systems. This gives you
great power and options.
Here we demonstrate this with our
smallest system for monitoring temperature and humidity.
Sensor system by Defsystem to measure environmental temperature and humidity
This is actually our smallest system. Just measures temperature and humidity and stores it somewhere as JSON data with REST calls over HTTPS using Wi‑Fi.
That somewhere could be a database system such as Dydra by Datagraph GmbH and then the measurements could be visualized and analyzed in Observable, just as it is done for the sensor device to monitor bottle fermentation. In fact, this is what some initial versions of this system also did for the last two or three years.
Enter Home Assistant
But now we added the option to use the open source home automation system Home Assistant. From the perspective of the sensor system it is not a big change, as Home Assistant supports a HTTP Sensor, that is dynamically created when data is sent.
Technically, this is really quite similar to how we send data to Dydra. It is just a different target for the REST calls, the JSON data is a bit different, bearer authentication with long-lived access tokens works a bit different and the actual REST API is also a bit different than the one of Dydra. But in principle this is all quite the same. It is easy for us to support a new backend.
But what we gain is the full power of Home Assistant!
You can define dashboards to look at the live data and you can do that using the mobile app of Home Assistant:
Or you can do detailed analyses of long-term data:
Of course, the dashboards are also available in the web site version of the Home Assistant:
… and data analysis may make also more sense on a bigger screen using the web site:
Extending Home Assistant and more power
On top of just looking, you can define alerts via the mobile app, via e-mail or whatever is set up. And you can define more complex automations than this alerting. For example, if a light sensor detects that it got dark you could switch on a light via an actor.
We have done such things in the past but there the client supplied its own backend system. Now, Home Assistant can be in place of such a custom system. It comes with a great variety of options, integrations and add-ons, including a mobile app that you can use to control your system. You might still want a custom branded user experience in the end, but for an early prototype or proof of concept, this is a great option.