🛠 Beacon BLE 5 : le « hello radio » d'une puce sans Wi-Fi

The ESP32-H2 has no Wi-Fi stack: its "hello radio" is Bluetooth 5 LE. Tutorial: broadcast a named beacon using the NimBLE stack from ESP-IDF (menuconfig → Component config → Bluetooth → BLE). The H2 supports long-range Coded PHY (125 and 500 kbps, RX sensitivity down to −106.5 dBm), Bluetooth Mesh, and a TX power of −24 to +20 dBm — up to 100 mW with the optional +20 dBm setting, exceptional for a SoC in this price range (DevKitM-1 ≈ $10, Waveshare ESP32-H2-DEV-KIT ≈ $6.65). Code structure: nimble_port_init, host synchronization callback, construction of the advertising payload (flags + complete local name), then ble_gap_adv_start in connectable and discoverable mode. Test with a BLE scanner on your phone. Porting pitfall #1: any example copied from ESP32, C3, or C6 that touches Wi-Fi or Matter-over-Wi-Fi is simply not executable here. BLE coexists with 802.15.4 on the same 2.4 GHz radio — we will leverage this coexistence at the intermediate level.