Talking to a DDM18SD Energy Meter

I had obtained three samples of a DDM18SD DIN rail mounted energy meter unit. I got mine from a UK supplier on eBay, but they are available here at AliExpress and in many different places. The unit I obtained was a single phase unit for directly measuring up to 5A and 240V AC, but up … more

CO2 Monitor

I’ve had a low cost carbon dioxide (CO2) sensor sitting on my desk for over a year! I thought why not get this thing recording, as I have already done a load of work sending data to MQTT feeds. The CO2 sensor I purchased was the MH-Z14A. The datasheet is available here. I did a … more

COVID Cases Monitor

I wanted to produce a small display for simple items of data streamed/taken from the internet. My initial plan was to look at environmental monitoring, but this was Feb 2020 and covid-19 hit the UK about this time. I saw that the UK government were making the cases data publicly available & so I set … more

Creating a Weather Display

This post covers making an E-Paper display to show me the daily weather forecast. Obviously I can just use my phone to do this, but I wanted a free standing, battery powered display to show me this info quickly and easily. E-Paper is perfect as I can just get this info every few hours and … more

TTGO E-Paper Display

I picked up a really nice and low priced E-Paper display, called the TTGO E-Paper Series. Mine is the T5 V2.3, which uses a 2.19″ E-Paper display, has an SD card slot, a bit of flash memory, one I/O button and some clever power management ICs. It uses the ESP-32 WiFi System on a Chip … more