An Ethernet-enabled Geiger-Müller counter and environmental data logger based on the WIZnet W55RP20-EVB-PICO, with local microSD logging, a built-in web dashboard and optional remote server logging.

A standalone ESP32-based YouTube subscriber counter with three large 3-digit 7-segment displays, a TM1640 display driver, automatic brightness control, local web configuration, and Wi-Fi access point locking for networks that use range extenders with the same SSID.

A low-cost Geiger counter built around the Soviet SI3BG (СИ-3БГ) Geiger-Müller tube. Powered by three AA batteries, it displays CPM and µSv/h readings while reproducing the classic radiation click through a piezo buzzer.

A low-power ATTiny1614-based capacitive soil moisture sensor that chirps like a cricket when your plants need water. Runs for up to two years on two AAA batteries and requires no app, Wi-Fi, or cloud service.