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Turn an Old Android Phone into a Home Assistant Sound Sensor

Learn step‑by‑step how to repurpose an old Android phone as a sound sensor for Home Assistant using IP Webcam, RTSP streams, and the FFmpeg Noise integration.
7 February 2026 by
TechStora Editorial Board

Overview

Sound sensors can be used for many home‑automation tasks such as detecting a fall, a crying baby, or simply acting as a clapper to toggle lights. By turning an old Android phone into a network microphone you can feed audio into Home Assistant without any cloud services.

Required Materials

  • Old Android phone with Wi‑Fi
  • IP Webcam app (or any app that can output an RTSP audio stream)
  • Home Assistant instance on the same network
  • FFmpeg installed (built‑in on Home Assistant OS)

Set Up IP Webcam on the Phone

Install the IP Webcam app from the Play Store. In the app settings enable Audio mode (not “Audio only”) and keep the video feed disabled to save battery. Start the server; the app will display an HTTP address and port.

Build the RTSP URL

Home Assistant needs an RTSP stream, so convert the shown HTTP address to the following format:

rtsp://<IP_ADDRESS>:<PORT>/audio

Replace <IP_ADDRESS> and <PORT> with the values shown on the phone.

Add FFmpeg Noise Integration

Edit configuration.yaml (or use the UI file manager) and add a ffmpeg_noise sensor:

  • platform: ffmpeg_noise
  • name: Phone Sound Sensor
  • input: rtsp://IP_ADDRESS:PORT/audio
  • Optional parameters: noise_threshold, reset_threshold, duration, reset

Restart Home Assistant to load the new sensor.

Create an Automation

Use the new sensor to trigger actions. A simple clapper automation might look like:

  • Trigger: state change of sensor.phone_sound_sensor to “on”
  • Action: toggle a light (e.g., light.bedroom)

You can customize the action to set brightness, color, or control multiple devices.

Tips & Alternatives

  • Use an app that streams audio only to reduce battery drain.
  • If you run Home Assistant in a Docker container, install FFmpeg on the host.
  • Samsung Galaxy devices can be repurposed via the Galaxy Upcycle program for SmartThings.
  • Consider adding a motion or light sensor to the same phone for richer automations.
  • Reusing old phones reduces e‑waste and extends the device’s ROI.