A free, hands-on Bluetooth Low Energy course. Every lesson runs on your own computer, with working code in 12 languages and no hardware to buy.

Learn Bluetooth Low Energy by running it. This free course starts with your first scan and ends with a connection that streams data. Every lesson runs on your own computer, in your language, with nothing to buy.

How each lesson works

Each lesson teaches one idea and has you run it:

Concept. A short explanation and one diagram.
Code. A complete program in C++, C, Python, Java, Rust, Node.js, React Native, Kotlin Multiplatform, Swift, Dart, Delphi or Android. Pick your language once and every lesson opens in it.
What you should see. The output that tells you it worked.
Exercise. One change to make on your own.
Troubleshooting. The fixes for the problems learners hit most often.
Tool. A free SimpleBLE browser tool for the lesson's topic.

What you need

A computer with Bluetooth. Windows, macOS or Linux.
SimpleBLE for your language. Installation lists the package for each language. For Python, run pip install simplepyble.
A device to talk to. A phone with nRF Connect for Mobile, a free app for Android and iOS, or a second computer running these lessons.

A computer without Bluetooth uses an nRF52840 USB dongle with the free Dongl firmware. The dongle appears as a Bluetooth adapter next to the computer's own.

Module 1: First contact

Find the devices around you and read what they broadcast.

1. What Is Bluetooth Low Energy (BLE)?

How BLE differs from Bluetooth Classic, how devices exchange data, and your first program.

2. BLE Central and Peripheral Roles

The roles devices play, and which ones are around you.

3. Scan for BLE Devices From Your Computer

Discover nearby devices and find the closest one.

4. Read BLE Advertisement Data

Names, manufacturer data, services and transmit power.

5. BLE RSSI: Signal Strength and Distance

Watch signal strength change as a device moves.

Module 2: Advertising

Make your computer visible and broadcast data of your own.

6. BLE Advertising

Advertising channels, packet types, scan responses and extended advertising.

7. BLE Manufacturer Data and Beacons

Company identifiers and the iBeacon and Eddystone formats.

8. Advertise BLE From Your Computer

Make your computer a peripheral that a phone can find.

9. BLE Advertising Interval and Discovery Time

How advertising and scan timing decide how fast a device is found.

Module 3: Connections and GATT

Connect to a device and exchange data with it.

10. Connect to a BLE Device

Open a connection, list its services and disconnect cleanly.

11. GATT Services and Characteristics

How a connected device organizes its data.

12. Bluetooth UUIDs

16-bit and 128-bit UUIDs, standard and custom.

13. Read and Write BLE Characteristics

Read values, and write with and without a response.

14. BLE Notify vs Indicate

Receive new values the moment they change.

15. BLE MTU and Throughput

How much data fits in a packet and how fast it moves.

16. BLE Connection Interval, Latency and Timeout

How connection parameters trade power for speed, and who sets them.

Coming next

Module 4: Build a peripheral. Serve GATT from your computer, build a heart rate service end to end, and connect your own central to it.
Module 5: Real devices. Read a heart rate strap, test your nRF or ESP32 devkit, and keep a device connected with a reconnect loop.
Module 6: Debugging and shipping. Disconnects, error codes, HCI logs, addresses and privacy, OS permissions and concurrency.

Go deeper

The Fundamentals pages are the reference for each topic, and the Recipes show the patterns for production code. The free SimpleBLE tools decode advertisements, look up UUIDs, validate connection parameters and more, in the browser.

SimpleBLE is a source-available Bluetooth Low Energy library for Windows, macOS, Linux, iOS and Android. The course uses it so the same lesson runs on every operating system and in every language.

Learn Bluetooth Low Energy: Free BLE Course