I received a subway emergency brake from a friend, which I connected to an ESP32. When activated, an I2C display shows an alarm and sends notifications to mobile phones.

Technical details

  • ESP32 microcontroller with WiFi
  • I2C display for status information
  • Push notifications via the Pushover API
  • Discord integration for alerts
  • Custom 3D-printed case

Future plans

  • Adding a speaker and microphone for intercom functionality between the server room and my room
  • Two-way communication
  • Web interface for configuration