KapaLa Moksha – Quiz Buzzer

March 23rd, 2009 by

A few months ago, I conducted a Kannada quiz for the Sacramento Kannada Sangha. Since people were fond of buzzer rounds, they requested me to have one. I hate buzzer rounds because it is very hard to arbitrate who hit the buzzer first. To solve this problem, I rigged up a micro-controller based Quiz Buzzer which talks directly to a computer via RS232 and clearly displays which team hit the buzzer first! Since we had a huge screen and a projector set up at the location, the entire audience could see the team number as soon as someone hit the buzzer.

I got some overwhelmingly good response for the buzzer and I decided to make it available for download.

KapaLa Moksha — Quiz Buzzer v0.1


  1. Supports up to 8 teams
  2. Communicates with a computer via RS232
  3. Windows software which displays team number on screen is included
  4. Additional LCD display which shows team number and other debug data

Hardware requirements

  1. PSoC CY3210 PSoCEVAL Kit. I had this kit from a course I had taken in grad school. The PSoC is a very versatile platform and facilitates rapid implementation on hardware, which is exactly what you are looking for when you are trying to rig a project in 3hours.
  2. A computer with a RS232 port
  3. Lots of wires and n* push button switches

*n = number of teams < 8

Thats it!

Downloads and implementation instructions

  1. Get the kit and connect n switches between Port A ( or whichever posrt you choose to make the input) and ground.  Should look something like this
  2. dscf3521

  3. Download and burn HEX code availabe in the C source code package under the folder quizBuzzer\output\quizBuzzer.hex onto the PSoC chip. Or you can open quizBuzzer.soc in PSoC Designer(comes with the kit, or you can download it from www.cypress.com )
  4. Connect to a computer with an active RS232 port (NOTE: otherwise, the program will crash) and run this program
  5. Hit reset and press one of the team buttons. You will hear a buzzer sound form the computer and the team number will be displayed! Screenshot below



The thing is really nifty and can make audience very happy!

The Name: KapaLa Moksha in kannada stands for “One tight slap”.