Wireless Trivia Game Buzzers Using HopeRF RFM69

TV game shows follow a formula that hasn’t changed much in sixty years. The celebrity presenter, the glamorous assistant, the catch phrases, the gaudy plywood sets, the nervous contestants, and of course the buzzers.

If you want to do a trivia quiz of your own it’s easy enough to dispense with presenter, assistant, set, and catch phrase, but as well as the contestants you’ll still need the buzzers. You can make a mess of wires that the TV technicians of old would have concealed within that set, but in your home or at the pub that could rapidly become inconvenient.

[Larry] solved his trivia game buzzer problems by building a wireless buzzer set. It features 3D printed enclosures containing Adafruit Feather microcontrollers, and instead of wires it uses RFM69 900MHz radio modules. The master unit displays the quickest contestant on an OLED screen, it features a low power standby mode between button presses to save battery power, and care has been taken to add a random timing to button presses to try to avoid collisions.

The buttons themselves started with a 3D printed button working a single tactile switch, but moved to a set of three switches in a triangle after edge presses failed to activate the single switch.

We’ve featured a wired game show buzzer before, but for the complete game show experience how about this countdown timer?

2 thoughts on “Wireless Trivia Game Buzzers Using HopeRF RFM69

  1. “and care has been taken to add a random timing to button presses to try to avoid collisions.”

    Please explain how this works. If you have two button presses that are 10 ms apart, and you delay the early one by a random value of 10 ms, they’re still going to collide. It seems to me that all this is going to do is introduce errors into the results.

  2. Upon button press, the buzzer sends a packet to the base station and waits a random amount of time before reattempting if it does not receive an ack packet back. That way if there is deadlock, each buzzer will wait a small random amount of time and thus will break the deadlock.

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