Your old Android phone has a sensor suite that most IoT devices can only dream of

Old Android phones contain a rich sensor suite including gyroscope, ambient light sensor, microphone, barometer, magnetometer, and camera — hardware that rivals or surpasses dedicated IoT devices costing $30–$60 each. Rather than discarding them, these phones can be repurposed as smart home sensor nodes using tools like Home Assistant Companion or Tasker. Practical use cases include 3D printer monitoring, baby/pet monitoring, and garage door detection. Tips include keeping the screen off or using kiosk mode to manage heat, and factory resetting before deployment to free up CPU resources.