An HVAC Tech’s Journey in IOT

Incorporating swift-psychrometrics in my IOT build.

Over the last week or so, I’ve began my trip down the roll your own IOT sensor rabbit hole. And while this story is not about making the sensor or relays, it is about incorporating my recently open sourced swift project called swift-psychrometrics. I feel I should at least mention my setup and how I got to where I am now in the project.

I currently have implemented, what some are calling, the most complicated residential HVAC system. Which I’ve deemed #FrankenSystem. I’m going to need some more logic / control than I can find in current residential control systems. Sure, I could install a commercial BMS system and program it, but they are expensive, and seems a little less fun than learning / creating my own (and controlling the data from it).

Setup

I’ve got Home Assistant running on a raspberry-pi, the sensor / relay pack is created using ESPHome and sending MQTT messages. That may sound heavy / complicated, however most folks who have a little knowledge of IOT likely know those terms. Currently I’m using an ESP-32 development board, an 8 channel relay (which is overkill for what I will talk about in this article) and a DHT-11 temperature / humidity sensor (I will upgrade to a better sensor after prototyping is complete). All of these items were relatively…