I gave this a try: It seems to be a reliable indicator when a battery is stone dead. The trick is to drop the battery vertically. Neat!
It turns out that when the alkaline in a battery wears down, it produces a gas that fills the inside. So if you’ve got a box of random batteries you want to test, and don’t have access to a voltmeter or any other device, you can simply drop them vertically a short distance onto a hard surface. A charged battery will make a solid thump sound and often remain standing, while a dead battery makes a muffled sound, bounces repeatedly, and then topples over.
Adafruit has had paid day off for voting for our team for years, if you need help getting that going for your organization, let us know – we can share how and why we did this as well as the good results. Here are some resources for voting by mail, voting in person, and some NY resources for our NY based teams as well. If there are additional resources to add, please let us know – adafruit.com/vote
Stop breadboarding and soldering – start making immediately! Adafruit’s Circuit Playground is jam-packed with LEDs, sensors, buttons, alligator clip pads and more. Build projects with Circuit Playground in a few minutes with the drag-and-drop MakeCode programming site, learn computer science using the CS Discoveries class on code.org, jump into CircuitPython to learn Python and hardware together, TinyGO, or even use the Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for CircuitPython, MakeCode, and Arduino. It has a powerful processor, 10 NeoPixels, mini speaker, InfraRed receive and transmit, two buttons, a switch, 14 alligator clip pads, and lots of sensors: capacitive touch, IR proximity, temperature, light, motion and sound. A whole wide world of electronics and coding is waiting for you, and it fits in the palm of your hand.