PCWorld explains how to create an affordable CO2 air quality monitor using a Raspberry Pi and MH-Z19C sensor for under $40. This DIY project helps monitor indoor air quality since high CO2 levels ...

The Audio-Technica ATH-R50x look and sound great, and they benefit from their open-ear design in ways that have made them my ...

A reliable indicator of the air quality in offices, classrooms, or living rooms is the CO2 content. In fresh air, the concentration of carbon dioxide is around 400 ppm. This stands for “parts per ...

Resistance standards are incredibly useful, but like so many precision references they require regular calibration, ...

Part 1 in this series covered defrost cycle problems in heat pumps. Now, let's discuss the second major winter issue: heat pumps stuck in one mode. The customer calls and says the system won't switch ...

Some kind of continuity beeper has been a standard piece of gear since the dawn of electronics. Sure, you probably have an ohm meter, but sometimes you don’t care about the actual resistance. You just ...

For around $25, the Neoteck TS20D is a fully-featured, well-made, and decently accurate tool that will handle most multimeter-related tasks. It's small enough to drop into a pocket or toolbox, durable ...

High Performance HF Power meter using Arduino and a Directional Coupler This device can measure power over a wide dynamic range from 10uW to 1 KW and will derive SWR for a 50 Ohm load The front end ...

Your Windows 11 laptop has a secret power setting that's seriously useful - how to find it ...

We tested popular wideband O₂ controllers against lab-grade equipment to see how accurate their lambda readings really are ...

I reassured him and sent him to get another blood specimen drawn without a tourniquet. Why? Because I suspected that the ...