While recalling the fun one could have with the project kits and parts found in the Radio Shack of the 1970s, I found a little board I made in 1978 (as usual stumbling across it while looking for something else). Every part on this thing came from Radio Shack. The IC is a National Semiconductor LM3914N, which is a 10-LED bar/dot display driver which at the Shack cost $2.49. Solderless breadboards were a new thing back then, with CSC (that is Continental Specialties Corp.) being the primary vendor at the time. Radio Shack offered the perma-proto board seen here for about $1.79. The LEDs were sold in packs of 2 for $0.79 and with the wire, switch and a few passive parts the entire project cost about $10. The short demo videos show the bargraph and dot display modes.
I went on to make a stereo VU meter later that summer, again all parts from Radio Shack:
And while it came with a data sheet, remember–this was Radio Shack–they had Forrest Mims notebooks. This exact circuit is used twice:
I went on to do more with the LM3915, such as build a 70-LED spectrum analyzer. However I will save that for another day. (read: I have to find it!)
We are angry, frustrated, and in pain because of the violence and murder of Black people by the police because of racism. We are in the fight AGAINST RACISM. George Floyd was murdered, his life stolen. The Adafruit teams have specific actions we’ve done, are doing, and will do together as a company and culture. We are asking the Adafruit community to get involved and share what you are doing. The Adafruit teams will not settle for a hash tag, a Tweet, or an icon change. We will work on real change, and that requires real action and real work together. That is what we will do each day, each month, each year – we will hold ourselves accountable and publish our collective efforts, partnerships, activism, donations, openly and publicly. Our blog and social media platforms will be utilized in actionable ways. Join us and the anti-racist efforts working to end police brutality, reform the criminal justice system, and dismantle the many other forms of systemic racism at work in this country, read more @ adafruit.com/blacklivesmatter
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.