old computers

This Old House's Ross Trethewey explains MERV filter ratings and how air filtration works, then shows how to build a localized DIY air filter, including a box fan with multiple filters.

A guided Wim Hof breathing session of three rounds at a slow pace, building from a 30 second to a 90 second breath hold. An on-screen bubble animation helps you keep the rhythm.

DIY Perks shows how to modify devices that use older USB connectors so they charge and connect over USB Type-C. He solders in a USB-C connector board and works through cases such as dongle-dependent gadgets and a mouse receiver.

NightHawkInLight shows how to make radiative sky cooling paint from grocery and hardware store materials, including a novel calcium carbonate microsphere synthesis. The paint can cool a surface below ambient air temperature in direct sunlight without electricity.

NightHawkInLight shows how to make ultra-white radiative paint that cools surfaces below ambient temperature without electricity. He walks through the research papers and the household-materials process.