[mircemk] had previously built a frequency counter using an Arduino, with a useful range up to 6 MHz. Now, they’ve implemented a new design on a far more powerful STM32 chip that boosts the ...

[Wolf] sent in this site a while back, and I thought that this frequency meter how-to looked pretty useful. It’s based on an Atmel AT89C52 and a gutted multi-meter. The circuit isn’t too bad.

Smart meters provide detailed information so a customer can make choices about how and when to use energy and save money, ...