Ble

No app install. No Play Store. No pairing. Open your phone’s browser, accept a certificate warning, and see live voltage readings with GPS coordinates — pushed over an encrypted WebSocket every 400ms. The path from Bluetooth to this point took 5 iterations, one afternoon, and an AI coding agent that tested every change on real hardware.

A complete Bluetooth voltage monitoring system — ESP32 reads voltage via ADS1115 ADC, broadcasts over BLE GATT, and an Android app displays live readings in real time. Built end-to-end in ~6 hours across 3 platforms.

The goal: measure voltage wirelessly and display it on your phone. Simple enough, but it means touching embedded C++, Bluetooth protocols, and Android Kotlin — all in one session. Here’s how the 6 hours broke down and what we learned along the way.