Have you ever seen a pocket calculator from the 1970s? If you have, you know that many used a series of tiny, red, LED seven-segment displays. These displays used little “bars” of light-emitting material which were placed behind little magnifying bubbles to make them more readily visible. They were very crisp and readable, and used a lot less power than vacuum fluorescent displays (VFD), which were also in use at that time.
I recall the little LED bubble displays were at one time in all sorts of handheld electronics and, in a slightly different form, watches. By the time LCDs became cheap in the late 1970’s, the more power-hungry LED display was on its way out.
I was pleasantly surprised back in 2011 to find on ebay a seller with numerous rails of HP 5082-7433 LED displays. These are three-digit displays in a 12-pin standard DIP format. I bought a few rails since the price was good. I’ve a tendency to get “stuff” and then never get around to using it so I decided this time there would be a project to make use of all the displays.
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.