This is a four player Quiz buzzer system.  The controller is designed with Ready & Reset buttons and will let you know who answered first,  There's also the option to pass the question to the remaining players that haven't answered yet!

This makes use of the nRF24L01 wireless devices which use 2.4GHz to transmit and receive.

I have also included an integrated lithium charge module based on the TP4056 chip to charge an internal 18640 battery.

The four buttons each contain an Arduino Pro MINI.

The buttons are wired up like this:

The main controller uses an Arduino Nano, although it could use a mini instead. This controller also connects to a DFPlayerMini board to provide sound effects every time a button is pressed.

The controller is wired up like this:

The source code can be downloaded from https://robsmithdev.co.uk/youtube/wirelessbuzzer.zip

For more information, and full build, see the YouTube Video:

3D models for Printing:

Thingiverse: https://www.thingiverse.com/thing:5396155
Tinkercad: https://www.tinkercad.com/things/k7JUDiFv1wr?sharecode=BaPiGkdqKju71d5xkFrCgnxJhQCo4WVAP1QIDcCe1sk

Parts List (Affiliate links)

nRF24L01+: https://amzn.to/3GxN7Hz (x10), https://amzn.to/3LLdtqn (x5)
nRF24L01+PA+LNA (Longer Range): https://amzn.to/3lKRe9i
nRF24L01+ 8-Pin Adapter: https://amzn.to/3z2A4Mi
TP4056 Based Charge/Boost Converter: https://amzn.to/3sYHXyx or https://amzn.to/3sWtLGt
18650 Battery Compartment: https://amzn.to/3GgvOdI
Arduino Pro Mini (16Mhz, 5V): https://amzn.to/3x8pnFF
FT232RL USB to TTL Converter (for programming the Arduino): https://amzn.to/3wLZRpf
Official Arduino Nano (Recommended): https://amzn.to/3FVaEBX
Arduino Nano (CH340 Version): https://amzn.to/3L3FLfv
DFPlayer Mini: https://amzn.to/38t9dOx
Red 10cm (4 inch) Arcade Button: https://amzn.to/39QotoZ
Yellow 10cm (4 inch) Arcade Button: https://amzn.to/38ueTI2
Green 10cm (4 inch) Arcade Button: https://amzn.to/3PgEMf6
Blue 10cm (4 inch) Arcade Button: https://amzn.to/3sx4jaa
Smaller Arcade Buttons (6cm) Alternative: https://amzn.to/3L8IT9Y
5V LED Lamps: https://www.arcadeworlduk.com/products/awuk-5v-10mm-wedge-base-led.html (not a sponsor)
M3 10mm Countersunk Screws: https://amzn.to/3MejVqM
M3 Metal Threadded Screw Inserts: https://amzn.to/3rgwhqB
Red PLA Plastic Filament: https://amzn.to/3yz7Bh2
Yellow PLA Plastic Filament: https://amzn.to/3swjccU
Green PLA Plastic Filament: https://amzn.to/37Ez45K
Blue PLA Plastic Filament: https://amzn.to/3yvmdxS
Spade Connectors: https://amzn.to/3w7GpUQ
Assorted 5mm LEDs: https://amzn.to/3LMT3gD
Plastic Chrome LED Panel Mount Holder: https://amzn.to/39Qnrtf
Assorted Resistors: https://amzn.to/3MRX6th
Wire Stripping Tool: https://amzn.to/321om6g