DIY Home Automation

To calculate and monitor the performance of my heat pumps (COP), I added several DS18B20 temperature sensors and a current sensor to measure the compressor's power input.

The temperature sensors are mounted in all relevant locations on the heat pump, such as the compressor discharge, and they terminate at a common ESP32. From there, the data is sent via MQTT to my Node-RED and CodeSys PLC. //Please don't judge me for my power supply. ;)

The COP calculation is still a bit off, but it is improving, and I can monitor the performance and power consumption over time via InfluxDB.

I've been dealing with the persistent failure of my old 433 MHz remote-controlled plugs. The issue likely stems from their inadequate capacitor power supplies, combined with my home voltage consistently exceeding their design specifications. Living near a transformer station means I can experience voltages up to 242 VAC. It's clear that an upgrade is necessary.

I’ve decided to switch to TASMOTA-compatible smart plugs from Amazon. Most of these plugs are built on the ESP32 platform with TASMOTA firmware, allowing seamless connection through MQTT.

After conducting some data probing, I successfully developed a flow in Node-RED. (Next time, I’ll be sure to consult the documentation first: https://tasmota.github.io/docs/MQTT.)

Additionally, coding this in Codesys-PLC is a feasible option as well.

(I got help from Grammarly by using AI prompts)

I finally managed to put all my raspberry pies into one cabinet: 

The heart of it all is still a Raspi3 with a codeSys SoftPLC running on it: 

It is snowing here in Austria. So, I spent some time porting a dewpoint calculation method to SCL (ST) and made a Function Block (FB):

https://github.com/MakeMagazinDE/Taupunktluefter/blob/main/Taupunkt_Lueftung.ino

Playing with your smart home is all fun until it also controls the heating ;) I use the temperature readout from my home-buttons as an external reference to control two heat pumps via node-red.  If the home-button fails (does not call for >35min) the PLC switches to the internal reference sensor. 

Most of the control logic happens on the PLC level. Only the communication with Mitsubishis melCloud takes place on the nodered. 

I was testing some DS18B20 Temperature Sensors. I hope to connect up to 8 Sensors via a 50m CAT cable to the AI-modules. (Arduino 2650)

This is how I combine the messages from 4 buttons into one.

So my PLC does not have to subscribe to too many topics and I can use each button input as a boolean. 

They look and feel great. 

To save on MQTT-subscribing-blocks on my Soft-PLC (Codesys) I summarized the buttons in Nodered:

After contemplating a DIY solution for physical light switches I stumbled upon a listing on Tindie. These https://www.tindie.com/products/plab/home-buttons-mini/ have four buttons and transmit temperature and humidity via MQTT.  So I decided to give them a try. -I'll update you as soon as they arrive. 

I decided to put two separate power supplies in. The bigger one is connected to most of the 24VDC-LED-strings (~300W) and the smaller PS supplies power to 24VDC IKea drawer lights and some utilities.  

This helps to save on stand power because the big 480W supply only gets switched on when someone turns on a light. In contrast, the Ikea drawer lights constantly need voltage to switch on via their internal sensors. 

To monitor the load on each supply I bought two cheap volt + amp-meters from Amazon. (the DIN-rail-holder is from Thingiverse: https://www.thingiverse.com/thing:3486542 )