The "brain" of the radio. It uses a state machine to manage whether the device is Advertising (broadcasting its presence), Scanning (looking for others), or in a Connection state exchanging data. 2. The Host (The "Brain")
To "put together" a BLE system, you need to understand three major building blocks that work in tandem: the , the Host , and the Application . 1. The Controller (The "Radio") Inside bluetooth low energy
Defines the "who's who." It determines if a device is a Central (like your phone) or a Peripheral (like a heart rate sensor). The "brain" of the radio
Bluetooth Low Energy (BLE) is essentially the "minimalist" sibling of classic Bluetooth, designed to stay in a near-zero power state and wake up only for tiny bursts of communication. This architecture allows devices like heart rate monitors and smart tags to run for years on a single coin-cell battery. The Host (The "Brain") To "put together" a
This is the hardware layer responsible for actually sending and receiving signals over the 2.4 GHz band.
Handles pairing and encryption to keep the data stream private. 3. The Application (The "User Interface") BLE with ESP32 tutorial part 1: the Server
Handles the "raw bits" and frequency hopping across 40 channels to avoid interference.