Raspberry Pi Pico W Bluetooth Low Energy

BT Server

• Gets temperature data from Pico's onboard thermometer
• Provides Generic Attribute Profile (GATT) Environmental Sensing service with Temperature Celsius characteristic, enabling clients to connect to it (connection is exclusive)
• If the client has enabled notifications, they are being sent every second
• When no client is connected, acts as a peripheral role in Generic Access Profile (GAP) and periodically sends out advertising packets that have the temperature embedded.

BT Client

• Scans devices within reach and looks for Environmental sensing service being provided
• When found, it connects to the server and looks for Temperature Celsius characteristic
• When found, it subscribes for notifications.

How to compile

mkdir build
cd build
export PICO_SDK_PATH=~/pico/pico-sdk  # Or where pico-sdk is cloned
cmake ..
make

How to run

Files bt_server.uf2 and bt_client.uf2 were created.
Hold BOOTSEL button on Pi Pico while connecting it to the PC.
Then copy one of the files to it.

Listen to Pico

Prints from Pico can be listened to on the terminal

sudo minicom -b 115200 -o -D /dev/ttyACM0

Resources

• Getting started with Pico
• Pico C SDK Documentation
• Pico W Bluetooth
• BTStack Documentation
• BTStack Repo