Stealing Joules From An Aluminium-Air Battery

While batteries are cheap and readily obtainable today, sometimes it’s still fun to mess around with their less-common manifestations. Experimenting with a few configurations, user [will.stevens] has assembled an aluminium-air battery and combined it with a joule thief to light an LED.

To build the air battery, soak an activated charcoal puck — from a water filter, for example — in salt-saturated water while you cut the base off an aluminium can. A circle of tissue paper — also saturated with the salt water — is pressed between the bare charcoal disk and the can, taking care not to …read more

Paul Jacob Evans


Measuring Air Flow with Ultrasonic Sensors

Measuring air flow in an HVAC duct can be a tricky business. Paddle wheel and turbine flow meters introduce not only resistance but maintenance issue due to accumulated dust and debris. Being able to measure ducted airflow cheaply and non-intrusively, like with this ultrasonic flow meter, could be a big deal for DIY projects and the trades in general.

The principle behind the sensor [ItMightBeWorse] is working on is nothing new. He discovered a paper from 2015 that describes the method that measures the change in time-of-flight of an ultrasonic pulse across a moving stream of air in a duct. …read more

Paul Jacob Evans

Air-Powered Wheelchair Goes Like The Wind

Electric wheelchairs are responsible for giving back independence to a great many people the world over. They do have their limitations, however, including long recharge times and a general aversion to large amounts of water. Being weatherproof is one thing, but taking one to a waterpark is another thing entirely. Fear not, for The University of Pittsburgh has the answer: the air-powered wheelchair.

Known as the PneuMobility project, the chair relies on a couple of compressed air tanks as a power source. They appear to be a of composite construction, which would cut down on weight significantly and help reduce …read more

Paul Jacob Evans