PWM over BLE UART

In this example, a smartphone app is used to transmit commands over BLE UART to control the PWM outputs and change the color of a RGB LED.

Description

Bluetooth version 4.0 is known as Bluetooth Low Energy or BLE. It is also referred by other names such as Bluetooth smart or Wibree. It is low power variation of original traditional Bluetooth standard. Like Bluetooth, it is also managed and maintained by Bluetooth SIG. Due to low power consumption and low power sleep modes.

Details

Ameba RTL8722DM is a low-power dual-band WLAN and Bluetooth Low Energy SoC by Realtek. The RTL8722DM also include memory for Wi-Fi protocol functions and application making it simple for anyone to develop various kind of IoT applications. At the same time it has a wide range of peripheral interfaces. With all these interfaces, it can connect to most of the electronics components like LEDs, temperature and humidity sensors, and so on.

More Resources:

If you need additional technical documents or the source code for this project. Please visit the official websites and join the Facebook group and forum.

Ameba Official Website: https://www.amebaiot.com/en/
Ameba Facebook Group: https://www.facebook.com/groups/amebaioten
Ameba Forum: https://forum.amebaiot.com/

Components

1 × RTL8722DM_MINI Microcontroller

1 × RGB LED Fiber Optics / Emitters

Build Instructions

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1

Setup

Connect the RGB LED with AmebaD [RTL8722DM_MINI]. The common LED pin may need to connect to 3.3V or GND depending on the type of LED (common anode / common cathode).
2

Programming

Ensure that the required app is installed on your smartphone, it is available at:
– Google Play Store:
https://play.google.com/store/apps/details?id=com.adafruit.bluefruit.le.connect

– Apple App Store:
https://apps.apple.com/us/app/bluefruit-connect/id830125974

Open the example, “Files” -> “Examples” -> “AmebaBLE” -> “PWM_over_BLEUart”.
3

Final Results

Upload the code and press the reset button on Ameba once the upload is finished.
Open the app on your smartphone, scan and connect to the board shown as “AMEBA_BLE_DEV” and choose the controller -> color picker function in the app.
Using the color selection wheel, saturation, and brightness sliders, choose a desired color and click select to send the RGB values to the board. You should see the RGB LED change to the matching color.