BLE (Bluetooth Low Energy) is a wireless technology with a short range, about ten metres, and very low power draw, designed for battery-powered objects. It is the go-to link between a sensor and a smartphone. Not to be confused with the “classic” Bluetooth of audio headsets: BLE carries no sound, it aims at sparse and brief data.
How does it work?
The data rate stays moderate, enough for readings and commands, not for a video stream. Like Wi-Fi, BLE is often built into the microcontroller, the ESP32 carrying both. Putting it to work is covered in Bluetooth LE on the ESP32. For a standalone sensor that has to last for months, pairing BLE with deep sleep is a classic: the device wakes only to transmit, and only briefly.
See also
- Wireless technologies — hub: where BLE sits among the others
- BLE on the ESP32 — putting it to work
- Wi-Fi — a high-rate alternative, but a hungry one
- Deep sleep — the low-power mode that pairs naturally with BLE
- ESP32 — a microcontroller with BLE (and Wi-Fi) built in