rainbow.MOV
In the CMD+O workshop 2019 of T-Systems (Deutsche Telekom), I have implemented a Bluetooth Low Energy (BLE) communication channel between a smartphone and an ESP32 microcontroller to control some LEDs (for a Christmas bauble 🎄). After the workshop's end, I have refactored and extended a moderately large amount of code (mainly because I unfortunately lost my original sketch file).
- ESP32-DevKitC development board
- WS2812b LED strip
- Power source
- Arduino IDE
- esp32 boards by Espressif Systems (then choose board ESP32 Dev Module with the correct port)
- Adafruit NeoPixel library by Adafruit
- USB to UART bridge VCP driver by Silicon Labs (can be installed as an optional update from Windows Update)
- nRF Connect app or any equivalent for BLE
Functional BLE service with two characteristics: ctrl to turn the LED strip on and off, and mode to switch between six main light orchestration modes.
Sent and received values over BLE are handled in each characteristic's two callback functions, which also consider malformed values.
mode |
Description |
|---|---|
red, orange, yellow, green, blue, indigo, violet, white |
Fill the entire strip with one color. |
allcolors |
The full strip displays one color after another. |
bounce |
One LED "bounces" from one end to the other end of the strip. When reaching an end, it changes to a random color. |
train, + one predefined color from the first mode (else white) |
Groups of LEDs move across the strip. |
rainbow |
All LEDs shift through different hues across the strip (example from NeoPixel). |
idle (the default for unsupported input) |
The strip brightens in white and then dims. |