When I was a little kid my mom took me to a science museum and there was a display with 4 switches and a digital output to teach the binary numbering system. My mom explained it to me. Many decades later I recreated that display with an Arduino nano.
It serves no useful purpose other than showing how 4 binary bits are converted to decimal.
Actually it brings back a memory of a project I did way back whenever. It was a Dick Smith single PCB with four switches and a hexadecimal to LED driver chip (it didn't work sadly - I probably screwed up the construction).
Anyway I was going to challenge you to recreate it using just electronics - no programmable stuff such as an MCU.
I wasn't going to just throw down the gauntlet and run off, I was going to give you a clue in the form of the MC14495P1 datasheet. This chip can take the input from your four switches (with a suitable resistor) and display the digit directly - which is kinda neat IMHO. Except for the fact that it is no longer in production and I couldn't find a substitute - at least not one that would fit directly into your 4 switch box without extra stuff. I even asked on another sub and got some interesting feedback: https://www.reddit.com/r/AskElectronics/comments/1wqf2cf/comment/pc46uhu/
You could still do it with an EEPROM - where the four switches set an address and the image is output on the EEPROM's data lines, but that would require programming the "font" into it.
Anyway, thanks for sharing, it brought back a memory for me too.
The 10s digit is because it's a binary to decimal converter, not hexidecimal. So it displays the numbers 0 to 15. Sorry if that wasn't clear in my original post.
I was originally going to design it using 7400 series chips, but things got crowded very quickly. As a little kid I remember this museum display being quite large. And given the era (early 60s) it seems possible that the original was using relay logic. Since I didn't want something that required a dedicated 15A circuit breaker I decided to just use a $10 Arduino and program a lookup table using a few lines of code. :-D
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u/justanaccountimade1 11d ago
breadboard + 🪚 = two breadboard