I needed a gateway that does not depend on a reliable WiFi connection, so Ethernet was the only option. The ESP32 processor is already designed to be used with Ethernet, using a LAN8720 interface module, which is available from Aliexpress etc. for under €3. This combination is well supported by the Arduino universe and the ETH library. To work properly, the module needs one minor modification, as described here or here. The MySensors website has instructions for how to build
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Link quality estimation for MySensors with NRF24
The NRF24 chips don’t provide a “Received Signal Strength Indicator” (RSSI) like a WiFi link does, but there is a way to get an indicator of link quality which was good enough for my application. When the NRF24 chip doesn’t receive an acknowledge for a transmitted message, it tries to send it again, up to 15 times. The number of retries needed to get the message to its destination (“automatic re-transmit count”, ARC) is held in a chip register, and that
Continue readingSoil moisture sensor with WiFi
In summer, I have a lot of potted plants out on the balcony, and I need to know when to water them. Indoors, most of my home automation gadgets are based on MySensors, but out on the balcony the signal is too weak, so I needed something WiFi-based, but without the high battery consumption typical of WiFi solutions. This was an opportunity to learn about optimizing a WiFi based gadget for low power consumption, and I will share my insights
Continue readingListen! … voice interaction with home automation
I have used an openHAB based home automation setup for several years now, and I am mostly happy with it … except in those very lazy moments where I just want to turn on a light, and wish I didn’t have to to pull my phone from my pocket, unlock it, open the openHAB app, navigate to the right UI page, and push a button. So … I decided it was time for voice-based interaction, Alexa style.
Continue readingRhasspy satellite with Raspberry Pi — UPDATED
I have several Raspberry Pies around the house, serving as voice interfaces (Rhasspy “satellites”), some of them also as media players using Kodi. They all have a ReSpeaker 2-Mics Pi HAT sound card, which contains two microphones and an audio output, connected to a small speaker.
Continue readingRhasspy with openHAB
I wanted my voice interaction solution to be fairly independent from openHAB, in order to have the option to switch to a different home automation controller in the future. That drove my design decisions in how to couple Rhasspy and openHAB.
The solution also needed to extensible: I expect to add more openHAB items for lights and other gadgets in the future, and I don’t want to have to manually edit lists of expected voice command sentences every time I do that.
I implemented three kinds of voice interaction: voice announcements, voice commands and voice questions and answers.
Continue readingBasic Satellite
I needed a few text-to-speech announcement nodes dotted around the house, to work with my openHAB and Rhasspy based home automation system. The basic idea was to find a cheap, small speaker with decent audio quality for voice output, and drive it from an ESP32-based board with ESP32 Rhasspy Satellite firmware, or my fork of it.
Continue readingMyDashboard for openHAB — home automation status at a glance
Before I leave the house, I want to see an overview of all relevant home automation variables: are all the windows and doors closed? are all the lights off? is my computer off? is the washer or dryer still running?
For this, I built a small, battery-powered display next to the front door. It has a Wifi connection to the home network, and pulls all relevant OpenHAB variables via its REST interface, every hour, and at the push of a button
Continue readingLight control for indoor plants
Winter is approaching, so I needed to bring my kitchen herbs collection inside, and I thought some artificial light might help to keep them thriving during the dark part of the year.
Continue readingFreezer door open alarm
We all need to minimize energy consumption these days, so what you really don’t want is for the freezer door to be not completely closed, accidentally, wasting a lot of electrical energy.
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