Adafruit will not be shipping USPS orders Monday February 18, 2019 for the federal holiday, Presidents Day.
Expedited USPS orders placed after 11am ET Friday February 15 will go out Tuesday February 19.
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.
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, or even use Arduino IDE. Circuit Playground Express is the newest and best Circuit Playground board, with support for MakeCode, CircuitPython, 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.