Hardware Connection

As shown in the diagram, connect the red, green, and blue pins of the RGB-LED module to the Arduino pins 1, 2, and 3 on the development board. The RGB-LED used here is a common cathode LED, with the common pin connected to GND. If using a common anode LED, it should be connected to 3.3V.


RGB-LED Module Schematic：https://oshwhub.com/jinleili/rgb-led-module


Code Analysis

 #include "BLEDevice.h"

 

 // Choose the RGB LED type

 // #define AnodeRGB

 #define CathodeRGB

 

 // Choose 3 PWM pins for RGB LED pins refer to the pinmap of using board

 #define LED_RED 1

 #define LED_GRN 2

 #define LED_BLU 3

 

 #define UART_SERVICE_UUID      "6E400001-B5A3-F393-E0A9-E50E24DCCA9E"

 #define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"

 #define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"

 

 #define STRING_BUF_SIZE 100

 

 BLEService UartService(UART_SERVICE_UUID);

 BLECharacteristic Rx(CHARACTERISTIC_UUID_RX);

 BLECharacteristic Tx(CHARACTERISTIC_UUID_TX);

 BLEAdvertData advdata;

 BLEAdvertData scndata;

 bool notify = false;

 

 void readCB(BLECharacteristic* chr, uint8_t connID)

 {

     printf("Characteristic %s read by connection %d \n", chr->getUUID().str(), connID);

 }

 

 void writeCB(BLECharacteristic* chr, uint8_t connID)

 {

     printf("Characteristic %s write by connection %d :\n", chr->getUUID().str(), connID);

     uint16_t datalen = chr->getDataLen();

     if (datalen > 0) {

         if (chr->readData8() == '!') {

             uint8_t command[datalen];

             chr->getData(command, datalen);

             if (command[1] == 'C') {

                 // print hex

                 printf("Color command R = %x G = %x B = %x \n", command[2], command[3], command[4]);

                 // print decimal

                 // printf("Color command R = %d G = %d B = %d \n", command[2], command[3], command[4]);

 #if defined(CathodeRGB)

                 analogWrite(LED_RED, command[2]);

                 analogWrite(LED_GRN, command[3]);

                 analogWrite(LED_BLU, command[4]);

 #elif defined(AnodeRGB)

                 analogWrite(LED_RED, (255 - command[2]));

                 analogWrite(LED_GRN, (255 - command[3]));

                 analogWrite(LED_BLU, (255 - command[4]));

 #else

                 printf("Error, please choose the RGB LED type \n");

 #endif

             }

         } else {

             Serial.print("Received string: ");

             Serial.print(chr->readString());

             Serial.println();

         }

     }

 }

 

 void notifCB(BLECharacteristic* chr, uint8_t connID, uint16_t cccd)

 {

     if (cccd & GATT_CLIENT_CHAR_CONFIG_NOTIFY) {

         printf("Notifications enabled on Characteristic %s for connection %d \n", chr->getUUID().str(), connID);

         notify = true;

     } else {

         printf("Notifications disabled on Characteristic %s for connection %d \n", chr->getUUID().str(), connID);

         notify = false;

     }

 }

 

 void setup()

 {

     Serial.begin(115200);

 

     pinMode(LED_RED, OUTPUT);

     pinMode(LED_GRN, OUTPUT);

     pinMode(LED_BLU, OUTPUT);

 

     analogWrite(LED_RED, 255);

     analogWrite(LED_GRN, 255);

     analogWrite(LED_BLU, 255);

 

     advdata.addFlags(GAP_ADTYPE_FLAGS_LIMITED | GAP_ADTYPE_FLAGS_BREDR_NOT_SUPPORTED);

     advdata.addCompleteName("AMEBA_BLE_DEV");

     scndata.addCompleteServices(BLEUUID(UART_SERVICE_UUID));

 

     Rx.setWriteProperty(true);

     Rx.setWritePermissions(GATT_PERM_WRITE);

     Rx.setWriteCallback(writeCB);

     Rx.setBufferLen(STRING_BUF_SIZE);

     Tx.setReadProperty(true);

     Tx.setReadPermissions(GATT_PERM_READ);

     Tx.setReadCallback(readCB);

     Tx.setNotifyProperty(true);

     Tx.setCCCDCallback(notifCB);

     Tx.setBufferLen(STRING_BUF_SIZE);

 

     UartService.addCharacteristic(Rx);

     UartService.addCharacteristic(Tx);

 

     BLE.init();

     BLE.configAdvert()->setAdvData(advdata);

     BLE.configAdvert()->setScanRspData(scndata);

     BLE.configServer(1);

     BLE.addService(UartService);

 

     BLE.beginPeripheral();

 }

 

 void loop()

 {

     if (Serial.available()) {

         Tx.writeString(Serial.readString());

         if (BLE.connected(0) && notify) {

             Tx.notify(0);

         }

     }

     delay(100);

 }

To know more: https://www.amebaiot.com/en/amebapro2-arduino-ble-pwm/

Compilation and Upload

 

Testing Process


Conclusion

This article introduces the Ai-Thinker BW21-CBV-Kit development kit to implement a Bluetooth RGB light. It covers the project introduction, code analysis, operation process, and effect display, providing a reference for development in wireless control and other IoT applications.