This project implements a low-power temperature measurement solution with connectivity to a peer-to-peer client via Bluetooth Low Energy (BLE).
- STM32WB15CG
- Download the project into the
STM32Cube_FW_WB_V1.22.1\Projects\NUCLEO-WB15CC\Applications\BLEdirectory. - Upload the
BLE_Stack_fullbinary to the coprocessor on your STM32WB15 board.
This project is a modification of the ST example BLE_HealthThermometer, originally designed for the STM32WB55. It replicates the same functionality on the STM32WB15 while introducing optimizations to minimize power consumption. Key enhancements include:
- Low-Power Advertising: Advertising interval increased from ~100 ms to ~1.5 s to reduce power usage.
- Standby Mode Support: The device enters standby mode between measurements, achieving an idle current consumption of approximately 1.1 μA.
- Connection Interval Adjustment: Upon connection, a request is made to change the connection interval to about 1 s to optimize power and performance.
- Power-Consuming Features Disabled: Unnecessary timers, LED blinking, button functions, and other peripherals are disabled to save power.
The ADC calibration and startup are consolidated within the HTSAPP_Measurement_start function, which is triggered by a timer. This approach ensures the ADC is enabled only when needed, optimizing power consumption by avoiding repeated calibration after waking from standby.
- Currently, calibration occurs at each measurement start.
- Potential improvement: Save and restore the calibration factor in software to reduce initialization time, assuming stable temperature and voltage during ADC power-down.
Measurements are triggered every 1 second by a timer initialized in the HTSAPP_Init function (hts_app.c).
To view the measured data using the ST BLE Toolbox application:
- Flash the program onto your Nucleo board.
- Launch the ST BLE Toolbox app and start scanning.
- Locate and connect to the device named
HTSTM. - After connection, select the Health Thermometer profile to display temperature data.
Caution : Issues and the pull-requests are not supported to submit problems or suggestions related to the software delivered in this repository. The STM32WB15 Low-Power Health Temperature Sensor example is being delivered as-is, and not necessarily supported by ST.
For any other question related to the product, the hardware performance or characteristics, the tools, the environment, you can submit it to the ST Community on the STM32 MCUs related page.
