ABACUS: Annika's Buzzers for Ascertaining Competitive Unique Signals

a lower-cost buzzer system for quizbowl competitions

the 3D models were based on https://www.thingiverse.com/thing:12686 and https://www.thingiverse.com/thing:1432052 and https://www.thingiverse.com/thing:1155457

check out the 'real' website for these!

I don't yet have detailed directions for building it, but you should definitely:

• get a PCB; you can fabricate these files, or I'll send you one (almost certainly for cheaper and potentially for free) if you contact me
• buy stuff from DigiKey (I don't know if this list is complete... you also will definitely need a speaker and some resistors and please, like, email me about this or Discord me or something if you are going to build this! I will help you!)
• print 10 of the 3D models for the buzzers and one of the 3D models for the case (which I still need to move the hole for the cord down to make it actually fit....)
• cut in half your 4p4c cables, push the wire ends through, solder the pushbutton switch to the right wires (this should be RED and GREEN but maybe double check with a multimeter?) and the LED positive lead to black and ground lead to yellow.
  • be sure to use electrical tape or heatshrink to make it not short itself out!
• glue the buzzers together, and maybe put some superglue around the bottom to stop people from yanking the cord out
• solder all the jacks to the PCB and resistors to limit the current to the LEDs to the board --- whatever you need to reduce 3.3V to a reasonable amount of current given the diode drop of the LED you're using, but I used 50-60 Ohms and mine haven't broken yet.
• solder the Raspberry Pi to the board, maybe with headers if desired
• put red + green LEDs and a switch into the case with wires attached, then attach the wires either directly to the board with solder in the appropriate places, or through headers
• glue the switch into the case, and close the case
• download the software and you're off!