Posted in home hacks Tagged chemical sensors, ESP32, home-assistant, hot tub, mqtt, ORP sensor, pH sensor Dip Your Toes In The Open Water Of Raspipool October 9, 2019 by Kristina Panos 25 Comments ...

That’s right, these parking sensors are powered by an Arduino board, and the only extra components that were used in the project are a HC SR04 ultrasonic sensor, an active buzzer, and jumper wires.

If you have allergies than you've likely considered picking up an air quality sensor for you house at some point. However, a good air quality monitor will run you upwards of $290.