Kahoot loudness meter

This program measures sound and sends to 'connected' UDP clients how loud the sound is in the range [0, 4096).

The server accepts UDP packets on port 3333. Clients have to send a 'connection packet' in order to be added to the 'connected client list'.

The server accepts a maximum number of 64 clients in this list. Once the connected list is full new clients are accepted if a client in the list has not sent a keep alive in the past 5 seconds. In this case the idle client is 'disconnected' and the new client is accommodated.

Protocol

Packets are prefixed with the packet id (1 byte).

• Packet ids:
  • Server-side:
    • Data packet:
      • Id: 0
      • Data:
        1. Unsigned-Short (2 bytes big-endian): It contains an unsigned short with the sound measurement
    • Disconnect packet:
      • Description: sent by the server when a client is removed from the connected clients list
      • Id: 2
      • Empty data
  • Client-side:
    • Connect packet:
      • Description: It asks the server to add the client address to the connected list to receive data packets
      • Id: 0
      • Empty data
    • Keep alive:
      • Description: It tells the server that the client is still alive
      • Id: 1
      • Empty data
    • Disconnect packet:
      • Description: it tells the server to remove the client from the connected list
      • Empty data

Hardware Required

This example can be run on any commonly available ESP32 development board: https://www.espressif.com/en/products/hardware/esp32/overview

Configure the project

make menuconfig

Set following parameter under Component Config -> WI-FI:

• Set Max number of WiFi dynamic TX buffers to 128.

Set following parameters under KahootLoudnessMeter Configuration Options:

• Set WiFi SSID of the Router (Access-Point).

• Set WiFi Password of the Router (Access-Point).

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

make -j4 flash monitor

(To exit the serial monitor, type Ctrl-].)