I built a small Android app that turns an Android phone into a fully functional ESPHome-compatible Bluetooth proxy so your devices keep reporting to Home Assistant even when you walk out of the house.
Background
After I released DJTPMS (a tyre-pressure monitor) and my Homeassistant Kawasaki Rideology BLE integration, I found a huge limitation, once I left the house the devices stopped reporting to Home Assistant. So I built a small Android app that turns any spare Android phone into an ESPHome-compatible Bluetooth proxy. it forwards BLE advertisements, supports GATT and native pairing (PIN/passkey), and works in foreground, background, and even on the lock screen.
Watch the demo: YouTube: COwJ1JocbVc
Grab the APK and source on GitHub: Zen3515/homeassistant-mobile-ble-proxy.
While I use wireguard vpn to connect back to home assistant, you can use it at home too.
Give it a try and may your old phone be useful again!