ESP32 Rotary Phone Interface

A project that interfaces a vintage rotary phone with an ESP32-S2 microcontroller, converting rotary dial pulses into MQTT messages for modern IoT applications.

Hardware Requirements

• LOLIN S2 Mini (ESP32-S2) development board
• Rotary phone with three connections:
  • Pulse pin (Green wire)
  • Dial pin (White wire)
  • Hook switch pin
• USB cable for programming

Features

• Converts rotary dial pulses to digital numbers
• Detects phone on/off hook state
• Publishes events via MQTT:
  • phone/dial: Dialed numbers
  • phone/hook: Phone state (picked up/hung up)
  • phone/status: Connection status

Setup

1. Install PlatformIO
2. Clone this repository
3. Configure WiFi and MQTT settings in src/main.cpp
4. Connect the rotary phone wires to the ESP32:
   • Pulse pin → GPIO 21
   • Dial pin → GPIO 17
   • Hook switch → GPIO 34
5. Build and upload using PlatformIO

Serial Monitor

• Baud rate: 115200
• Data bits: 8
• Parity: None
• Stop bits: 1

Dependencies

• PubSubClient (MQTT client)
• ESP32Ping (Network utilities)