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Bluetooth Low Energy is energy conversing wireless procotol that help IoT microcontroller to save a great deal of power as compared to using WiFi. Here we use Realtek's RTL8722 dual-band WiFi and BLE 5.0 IoT microcontroller to demo how to output PWM signal to a RGB led over BLE UART Materials Ameba D [RTL8722 CSM/DM] x 1 RGB LED Android / iOS smartphone Example Introduction 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. Refer to the other example guides for detailed explanations of the BLE UART service. Procedure Connect the RGB LED to the RTL8722 board following the diagram, the common LED pin may need to connect to 3.3V or GND depending on the type of LED (common anode / common cathode). 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”. 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. Code Reference The RGB values are sent as three consecutive bytes prefixed by “!C” characters. The “!” exclamation mark is used to indicate that the following data is a command, and the “C” character is used to indicate that the data is RGB values. The received UART message is checked in the callback function for “!C” first, otherwise it is treated as a regular message and printed to the serial terminal.
E-ink display comes in very handy in cutting power consumption when not refreshing the screen, it becomes more power conserving when combined with ARM Cortex M33 microcontroller-- RTL8722 from Realtek. This microcontroller sports dual-band WiFI and BLE 5.0 withh max clock at 200MHz, which make it possible to parse long string of a URL and generate a QR code locally. In this demo, we will show how to generate QR code and display it on a E-ink display. https://youtu.be/KYI5WBmC6ac
A BLE beacon broadcasts its identity to nearby Bluetooth devices, to enable the other devices to determine their location relative to the beacon, and to perform actions based on information broadcast by the beacon. Example applications of beacons include indoor positioning system, location-based advertising and more. From the definition of its purpose as a broadcast device, a BLE beacon thus cannot be connected to, and can only send information in its Bluetooth advertisement packets. There are several BLE beacon protocols. The Ameba BLEBeacon library supports the iBeacon and AltBeacon protocols.
BLE connections use a server client model. The server contains the data of interest, while the client connects to the server to read the data. Commonly, a Bluetooth peripheral device acts as a server, while a Bluetooth central device acts as a client. Servers can contain many services, with each service containing a some set of data. Clients can send requests to read or write some data and can also subscribe to notifications so that the server can send data updates to a client. In this example, a basic battery service is set up on the Ameba Bluetooth stack. A mobile phone is used to connect the the Ameba peripheral device and read the battery data. GitHub page https://github.com/Realtek-AmebaApp/ Official pages https://www.amebaiot.com/en/ Facebook pages https://www.facebook.com/groups/AmebaIoT/