air quality

A University of Michigan Medicine demonstration of building a cheap DIY air purifier from a box fan and a HEPA or high-MERV filter using hardware-store parts. It explains why this helps against dust, smoke and viruses and ties it to local air quality readings.

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.

Chef Chris Young shows a simplified triple-cooked method for making crisp frozen fries in an air fryer, based on Heston Blumenthal's technique.

Tech Ingredients shows how to build a liquid panel with a specialty paint that, placed outside, cools below ambient air temperature. It demonstrates radiative sky cooling.

A This Old House segment where Richard Trethewey installs a heat exchanger that uses waste heat from a central air conditioner to heat a swimming pool.

Matt Risinger covers installing a Zehnder ERV fresh-air system in a tight passive house, explaining balanced ventilation, the benefits of heat recovery and the costs involved.

Matt Risinger demonstrates a blower door test on a house, using a fan to measure air leakage and find where air gets in and out. It shows how the test reveals the quality of the build.

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.

Dave Jones of EEVblog shows hand soldering of surface-mount parts, including drag soldering and tack-and-reflow of 0.5mm fine-pitch ICs, with solder paste and hot air.

A short walkthrough of a hack that tricks a Brother laser printer into accepting third-party toner by working around its genuine-toner check. It notes this may void the warranty.

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.

A short, nearly wordless demonstration of making sourdough pizza at home using a cast iron pan and the oven. It shows a Neapolitan-style result without a pizza steel or stone.

Technology Connections shows a cheap method for capturing analog video: a composite-to-HDMI upscaler feeding an HDMI capture dongle, aimed at digitizing home movies and VHS tapes.

A walkthrough of installing Synapse, Riot and Jitsi from scratch on Debian to run your own Matrix communication service. The description warns it is now quite outdated and links to updated material.

The Thought Emporium shows how to receive clear images directly from GOES-15, 16 and 17 and Himawari 8 geostationary weather satellites with software-defined radio. It covers the extra effort needed to receive GOES data.

Tech Ingredients builds a pair of large Voigt speakers and explains ported, transmission line and horn designs. It tests them in an anechoic chamber and uses constrained layer damping for the enclosure.