Home Assistant

Roger Cheng

Notes on Home Assistant Core vs Home Assistant Operating System

Once I decided to try Home Assistant, the next decision is how to run it. Installation documentation listed many options. Since I’m in the kick-the-tires trial stage, I am not yet ready to dedicate a computer to the task (not even a Raspberry Pi) so I quickly focused on running Home Assistant inside a virtualized environment on my home server. But even then, that left me with two options: run Home Assistant Core in a Docker container, or run Home Assistant Operating System in a virtual machine.

Reading into more details, I was surprised to learn that both cases run Home Assistant Core in a Docker container. The difference is that Home Assistant Operating System also includes a “Supervisor” module that helps manage the Docker instance, doing things like automatic updates (and rollback in case of failure), making backups, and setting up additional Docker instances for Home Assistant add-ons. (ESPHome dashboard is one such addon.) If I opt out of supervisor to run Home Assistant Core on my existing Docker host, I will have to handle my own updates, backups, and add-ons.

Since I already had a backup solution for data used by Docker containers running on my server, I decided to start by running Home Assistant Core directly. After running in this fashion for a week, I’ve learned a few facts in favor of running Home Assistant Operating System on a physical computer:

  • Home Assistant Core updates very frequently, three updates in the first week of playing with it. Thanks to Docker it’s no great hardship to pull a new image and restart, but it’d be nice to have automatic rollback in case of failure.
  • When browsing the wide selection of Home Assistant integrations, there’s usually a little “Add Integration” button that held the promise to automatically set everything up for us. When the thing is an addon that requires running its own Docker container (like the ESPHome dashboard) the promise goes unfulfilled because we’d need the supervisor module for that.
  • When managed by the supervisor, addons like ESPHome can be integrated into the Home Assistant user interface. Versus opening up a separate browser tab when running in a Docker container I manage manually. This also means an addon can integrate with Home Assistant permissions so there’s no need to set up a separate username and password for access control.
  • Some addons like the ESPHome dashboard requires hardware access. In the case of ESPHome, a USB cable is required for flashing initial firmware on an ESP8266/ESP32. Further updates can be done over the network, but that first one needs a cable. Some Docker hosting environments allow routing a physical USB port to the Docker instance, but mine does not.

I could work around these problems so none of them are deal-breakers. But if I like Home Assistant enough to keep it around, I will seriously consider running it on its own physical hardware. Whether that’d be a Raspberry Pi or something else is to be determined.

In the meantime, I will continue running Home Assistant Core in a container. The documentation even gave us a docker-compose.yml file all ready to go, but I was skeptical about running it as-is.

Roger Cheng

Window Shopping Home Assistant

I learned about Home Assistant in a roundabout way, but once I started looking at it, I saw an interesting new tool I want to add to my toolbox. It started off on my good side with description on the project’s home page: “Open source home automation that puts local control and privacy first.” I like everything about that sentence and the tone it sets for the project.

I was once very interested in the promises of having a “smart home” and I was one of the early adopters of a Nest thermostat. (Before they were acquired by Google.) However, several years of Nest thermostat ownership also soured me on the concept of home automation via cloud services. Every once in a while, a server I never knew existed goes down and I get an error message on my Nest. To Nest’s credit, when their backend goes offline the thermostat continues running the last program it remembers. So it would never be worse than a “dumb” thermostat. Unfortunately not all “smart home” devices has such a graceful failure mode. For example whenever AWS us-east-1 suffers an outage, I would read about people not being able to get into their house because their Alexa-enabled smart lock wouldn’t unlock. If my smart home fails, I want it to be my own fault.

With an aversion to this class of failure, I have not bought any more Nest devices and became cool to the whole smart home concept. But maybe that will change if I could have local control and execution, and that is something Home Assistant offers. This also means any data is stored on my home server instead on somebody else’s AWS/Azure/GCP instance. It is popular for people to run on a Raspberry Pi dedicated to the purpose, but I could also run it in a Docker container on my home server as I’ve been doing for many other software pieces in this project.

While I intend to start playing with Home Assistant with DIY nodes built from ESP8266/ESP32, it offers integration with many home automation systems beyond those running ESPHome. It can even integrate with Google Nest, Amazon Alexa, and the like. But there’s a catch: to integrate with cloud-based services I would then have to either (1) open my instance of Home Assistant to the internet, or (2) use Nabu Casa’s cloud-hosted Home Assistant service.

In the near term that would not be a problem because I’m going to leave my Nest as-is. Until I’m more comfortable with the system, I’m not going to let Home Assistant control anything with drastic failure modes like locking me out of my house. I’m going to start simple and keep stakes low.

Roger Cheng

Learned About Home Assistant From ESPHome Via WLED

I thought Adafruit’s IO platform was a great service for building network-connected devices. If my current project had been something I wanted to be internet-accessible with responses built on immediate data, then that would be a great choice. However, my current intent is for something locally at home and I wanted the option to query and analyze long term data, so I started looking at Home Assistant instead.

I found out about Home Assistant in a roundabout way. The path started with a tweet from GeekMomProjects:

A cursory look at WLED’s home page told me it is a project superficially similar to Ben Hencke’s Pixelblaze: an ESP8266/ESP32-based platform for building network-connected projects that light up individually addressable LED arrays. The main difference I saw was of network control. A Pixelblaze is well suited for standalone execution, and the network interface is primarily to expose its web-based UI for programming effects. There are ways to control a Pixelblaze over the network, but they are more advanced scenarios. In contrast, WLED’s own interface for standalone effects are dominated by less sophisticated lighting schemes. For anything more sophisticated, WLED has an API for control over the network from other devices.

The Pixelblaze sensor board is a good illustration of this difference: it is consistent with Pixelblaze design to run code that reacts to its environment with the aid of a sensor board. There’s no sensor board peripheral for a WLED: if I want to build a sensor-reactive LED project using WLED, I would build something else with a sensor, and send commands over the network to control WLED lights.

So what would these other network nodes look like? Following some links led me to the ESPHome project. This is a platform for building small network-connected devices using ESP8266/ESP32 as its network gateway, with a library full of templates we can pick up and use. It looks like WLED is an advanced and specialized relative of ESPHome nodes like their adaptation of the FastLED library. I didn’t dig deeper to find exactly how closely related they are. What’s more interesting to me right now is that a lot of other popular electronics devices are available in the ESPHome template library, including the INA219 power monitor I’ve got on my workbench. All ready to go, no coding on my part required.

Using an inexpensive ESP as a small sensor input or output node, and offload processing logic somewhere else? This can work really well for my project depending on that “somewhere else.” If we’re talking about some cloud service, then we’re no better off than Adafruit IO. So I was happy to learn ESPHome is tailored to work with Home Assistant, an automation platform I could run locally.