IMadeAThing on karl

Monitoring HVAC system with ESPHome

Sat, 02 Nov 2024 00:00:00 +0000

Using ESPHome to Monitor HVAC System

Here’s a quick “show-and-tell” about a recent project I completed.

The concept

I’m not sure how I first came across the idea of measuring air pressure drop across a filter to gauge its remaining life, but I remember thinking it was a great idea.

Conceptual diagram for the project.

The idea has been lurking in the back of my mind for a while, but I never got around to implementing it… until now.

Watch Band RFID fob

Sat, 14 Sep 2024 00:00:00 +0000

Watch Band RFID fob

This is a quick project to create a wearable RFID fob that can be easily attached to a watch band. The idea is to have a small RFID tag that can be used for various purposes, such as access control or identification that is - more or less - as convenient as a surgically implanted tag, but without the need for embedding anything in your body.

I made a thing: GPS/PPS clock source for ntpd

Sat, 15 Oct 2022 00:00:00 +0000

Tip

This is just a ‘pointer’ post.

All the details are in the kquinsland/yet-another-gps-pps-opnsense repo on github.

For the longest time, I had a dedicated raspberry pi with a GPS module acting as the ntp server for my home network. I chose to use a dedicated host for this because my router - at the time - did not have a serial port that I could leverage.