How to use BLE with: Seeed XIAO nRF52840 Sense

Products & Technology
10

This getting more and more confusing…
Now I have solved the microphone problem, works ok. But now I can´t connect the BLE. My computer sees the SEEED, but can´t connect…
Can you see whats wrong with this code? I have tryed everything soon, even asked ChatGPT… no solution…

#include <ArduinoBLE.h>
#include <mic.h>

// BLE HID service and characteristic
BLEService hidService("1812"); // HID service UUID
BLECharacteristic inputReportCharacteristic("2a4d", BLERead | BLENotify, 8);

// Microphone settings
#define SAMPLES 800  // Number of audio samples per cycle
mic_config_t mic_config{
  .channel_cnt = 1,
  .sampling_rate = 16000,
  .buf_size = 1600,
#if defined(ARDUINO_ARCH_NRF52840)
  .debug_pin = LED_BUILTIN  // Debug pin (LED_BUILTIN)
#endif
};

NRF52840_ADC_Class Mic(&mic_config);  // Initialize the microphone
int16_t recording_buf[SAMPLES];   // Buffer to store audio data
volatile uint8_t recording = 0;
volatile static bool record_ready = false;
int soundLevel = 0;  // Calculated sound level from the microphone

// Threshold to trigger keypress
const int threshold = 100;

// Function to send 'A' as a keypress
void sendKeyA() {
    uint8_t report[8] = {0};  // HID Report: Modifier, Reserved, Key1, ...
    report[2] = 0x04;         // HID Keycode for 'A'

    // Send key press
    Serial.println("Sending 'A' key press...");
    inputReportCharacteristic.writeValue(report, sizeof(report));

    delay(10);  // Simulate keypress duration

    // Send key release
    report[2] = 0;  // Release the key
    inputReportCharacteristic.writeValue(report, sizeof(report));
}

// Callback function for PDM (Microphone)
static void audio_rec_callback(uint16_t *buf, uint32_t buf_len) {
    static uint32_t idx = 0;

    // Copy audio data from DMA buffer to our buffer
    for (uint32_t i = 0; i < buf_len; i++) {
        recording_buf[idx++] = buf[i];  // Store audio sample in the buffer

        if (idx >= SAMPLES) {
            idx = 0;
            recording = 0;
            record_ready = true;
            break;
        }
    }
}

void setup() {
    Serial.begin(115200);
    while (!Serial) { delay(10); }

    // Initialize BLE
    if (!BLE.begin()) {
        Serial.println("Starting BLE failed!");
        while (1);
    }
    BLE.setLocalName("XIAO BLE Keyboard");
    BLE.setAdvertisedService(hidService);
    hidService.addCharacteristic(inputReportCharacteristic);
    BLE.addService(hidService);
    BLE.advertise();

    // Initialize the microphone and set callback
    Mic.set_callback(audio_rec_callback);

    if (!Mic.begin()) {
        Serial.println("Mic initialization failed");
        while (1);
    }

    Serial.println("Mic initialization done.");
}

void loop() {
    BLEDevice central = BLE.central();  // Check if a central device is connected

    // If recording is done and audio data is available
    if (record_ready) {
        // Calculate sound level by summing and averaging the absolute sound strength
        soundLevel = 0;
        for (int i = 0; i < SAMPLES; i++) {
            soundLevel += abs(recording_buf[i]);  // Take the absolute value for each sample
        }
        soundLevel /= SAMPLES;  // Average sound strength

        Serial.print("Sound Level: ");
        Serial.println(soundLevel);

        // If sound level exceeds the threshold, trigger a keypress
        if (soundLevel > threshold) {
            if (central) {
                Serial.println("Loud sound detected! Device connected. Sending 'A'...");
                sendKeyA();
            } else {
                Serial.println("Loud sound detected, but device is NOT connected.");
            }
        }

        // Reset the status after processing the sound
        record_ready = false;
    }

    delay(10);  // Short delay for stability
}