Wireless-Trivia-Buzzers

What is it?

There will be four buzzer boxes and one main box. Each buzzer box will represent a team (Teams A, B, C, and D) and will have four buttons, one for each player. The main box will house a screen that allows the host to see which player buzzed in first and will also include a reset button to clear all buzzes. For the time being, I plan to include two modes. The first mode allows only one player per team to buzz in, any player from the team can buzz, but only the first buzz from that team will register. The second mode is a free-for-all, where all 16 players can buzz in individually, regardless of their team.

Backstory

Basically this idea came to me while me and a couple of friends were practicing for a trivia competition that my school's Classics club hosts semi-annually (with other neighboring schools). I realised that many other schools didn't have the funds to buy the "official" buzzers that all the other schools use, which means that they just end up using some horrible online version, which are very dependent on how good your wifi is. Moreover, these buzzers we're SO HEAVY and annoying to set up that half the time my friends and I didn't even bother practicing because we were too lazy to set up the buzzers and get an actual competition environment going.

Architecture & Features

Hardware

• Display: 16x2 LCD With an I2C Module
• Chip: ESP32
• Audio:
  • DAC: MAX98357A
  • Speakers: 2W Speakers
• Power: 9V Battery or USB-C

Pictures

3D Model

Wiring Diagram

PCBs

Buzzer Box

Main Box

BOM

Item	Purpose	Source	Price	Inventory
5x ESP32 (38 Pin) Dev Board	Controller	Link	$32.10	Owned
16x2 LCD with I2C Module	Output	Link	$3.47	Owned
Speakers	Output	Link	$2.99	Owned
5 LEDS	Output	Link	$0.50	Owned
MAX98357A	Output	Link	$2.53	Owned
17x Push Buttons	Input	Link	$10.25	Owned
16x Charger Wires (Any work)	Input	Link	$14.43	Owned
Micro SD Card Module	Input	Link	$1.28	Highway Provided
5x USB-C Port	Input	Link	$4.11	Owned
5x 9V Battery	Power	Link	$12.69	Highway Provided
5x 9V Battery Connector	Power	Link	$0.51	Owned
5x DC - DC Buck Converter	Power	Link	$4.65	Highway Provided
5x 3 Way (SPDT) Switch	Switch	Link	$0.41	Highway Provided
2.54mm Headers	Connector	Link	$0.84	Highway Provided
Buzzer Box PCB (w/ Shipping)	PCB	JLCPCB	$10.00	Highway Provided
Main Box PCB (w/ Shipping)	PCB	JLCPCB	$5.00	Highway Provided
		Total:	$105.76
		Total (Highway Provided):	$34.87