Stefan TabakovskiLori GrumJure UršičMark BreznikLuka Mali
Published

Boilarm

Never again do you have to check whether your water is boiling. Put on your headphones and let your phone notify you!

IntermediateFull instructions provided1 hour411
Boilarm

Things used in this project

Hardware components

Nano 33 BLE Sense
Arduino Nano 33 BLE Sense
×1
USB-A to Micro-USB Cable
USB-A to Micro-USB Cable
×1
Android device
Android device
×1

Story

Read more

Schematics

Schematic

Only a Bluetooth connection is needed.

Code

Boiling Water Recognition

Arduino
This is the arduino code used to recognize if water is boiling and send the information to your phone.
#define EIDSP_QUANTIZE_FILTERBANK   0

/* Includes ---------------------------------------------------------------- */
#include <PDM.h>
#include <vrenje_vode_inference.h>
#include <ArduinoBLE.h>
#include <BLEDevice.h>

/** Audio buffers, pointers and selectors */
typedef struct {
    int16_t *buffer;
    uint8_t buf_ready;
    uint32_t buf_count;
    uint32_t n_samples;
} inference_t;

static inference_t inference;
static signed short sampleBuffer[2048];
static bool debug_nn = false; // Set this to true to see e.g. features generated from the raw signal
BLEDevice central;
BLEService batteryService("180F");
BLEUnsignedCharCharacteristic batteryLevelChar("2A19", BLERead | BLENotify);


/**
 * @brief      Arduino setup function
 */
void setup()
{

 
    // put your setup code here, to run once:
    Serial.begin(115200);

    Serial.println("Edge Impulse Inferencing Demo");

    // summary of inferencing settings (from model_metadata.h)
    ei_printf("Inferencing settings:\n");
    ei_printf("\tInterval: %.2f ms.\n", (float)EI_CLASSIFIER_INTERVAL_MS);
    ei_printf("\tFrame size: %d\n", EI_CLASSIFIER_DSP_INPUT_FRAME_SIZE);
    ei_printf("\tSample length: %d ms.\n", EI_CLASSIFIER_RAW_SAMPLE_COUNT / 16);
    ei_printf("\tNo. of classes: %d\n", sizeof(ei_classifier_inferencing_categories) / sizeof(ei_classifier_inferencing_categories[0]));

    if (microphone_inference_start(EI_CLASSIFIER_RAW_SAMPLE_COUNT) == false) {
        ei_printf("ERR: Failed to setup audio sampling\r\n");
        return;
    }

    if (!BLE.begin()) {
     Serial.println("starting BLE failed!");
     while (1);
    }
    pinMode(LED_BUILTIN, OUTPUT);
    BLE.setLocalName("Vrenje");
    BLE.setAdvertisedService(batteryService); 
    batteryService.addCharacteristic(batteryLevelChar); 
    BLE.addService(batteryService); // Add the battery service
    BLE.advertise(); 
    Serial.println("Bluetooth device active, waiting for connections...");
    while (1) {
     central = BLE.central();
     if (central) {
     Serial.print("Connected to central: ");
     Serial.println(central.address());
     digitalWrite(LED_BUILTIN, HIGH);
     break;
     }
    }


}

/**
 * @brief      Arduino main function. Runs the inferencing loop.
 */
void loop()
{
    ei_printf("Starting inferencing in 2 seconds...\n");

    delay(2000);

    ei_printf("Recording...\n");

    bool m = microphone_inference_record();
    if (!m) {
        ei_printf("ERR: Failed to record audio...\n");
        return;
    }

    ei_printf("Recording done\n");

    signal_t signal;
    signal.total_length = EI_CLASSIFIER_RAW_SAMPLE_COUNT;
    signal.get_data = &microphone_audio_signal_get_data;
    ei_impulse_result_t result = { 0 };

    EI_IMPULSE_ERROR r = run_classifier(&signal, &result, debug_nn);
    if (r != EI_IMPULSE_OK) {
        ei_printf("ERR: Failed to run classifier (%d)\n", r);
        return;
    }

    // print the predictions
    ei_printf("Predictions ");
    ei_printf("(DSP: %d ms., Classification: %d ms., Anomaly: %d ms.)",
        result.timing.dsp, result.timing.classification, result.timing.anomaly);
    ei_printf(": \n");
    for (size_t ix = 0; ix < EI_CLASSIFIER_LABEL_COUNT; ix++) {
        ei_printf("    %s: %.5f\n", result.classification[ix].label, result.classification[ix].value);
    }

    // BLE:
    if ( result.classification[0].value > result.classification[1].value ) {
        if (central.connected()) batteryLevelChar.writeValue(1);
      }
    if ( result.classification[0].value < result.classification[1].value ) {
        if (central.connected()) batteryLevelChar.writeValue(0);
      }

   
    
#if EI_CLASSIFIER_HAS_ANOMALY == 1
    ei_printf("    anomaly score: %.3f\n", result.anomaly);
#endif
}

/**
 * @brief      Printf function uses vsnprintf and output using Arduino Serial
 *
 * @param[in]  format     Variable argument list
 */
void ei_printf(const char *format, ...) {
    static char print_buf[1024] = { 0 };

    va_list args;
    va_start(args, format);
    int r = vsnprintf(print_buf, sizeof(print_buf), format, args);
    va_end(args);

    if (r > 0) {
        Serial.write(print_buf);
    }
}

/**
 * @brief      PDM buffer full callback
 *             Get data and call audio thread callback
 */
static void pdm_data_ready_inference_callback(void)
{
    int bytesAvailable = PDM.available();

    // read into the sample buffer
    int bytesRead = PDM.read((char *)&sampleBuffer[0], bytesAvailable);

    if (inference.buf_ready == 0) {
        for(int i = 0; i < bytesRead>>1; i++) {
            inference.buffer[inference.buf_count++] = sampleBuffer[i];

            if(inference.buf_count >= inference.n_samples) {
                inference.buf_count = 0;
                inference.buf_ready = 1;
                break;
            }
        }
    }
}

/**
 * @brief      Init inferencing struct and setup/start PDM
 *
 * @param[in]  n_samples  The n samples
 *
 * @return     { description_of_the_return_value }
 */
static bool microphone_inference_start(uint32_t n_samples)
{
    inference.buffer = (int16_t *)malloc(n_samples * sizeof(int16_t));

    if(inference.buffer == NULL) {
        return false;
    }

    inference.buf_count  = 0;
    inference.n_samples  = n_samples;
    inference.buf_ready  = 0;

    // configure the data receive callback
    PDM.onReceive(&pdm_data_ready_inference_callback);

    // optionally set the gain, defaults to 20
    PDM.setGain(80);
    PDM.setBufferSize(4096);

    // initialize PDM with:
    // - one channel (mono mode)
    // - a 16 kHz sample rate
    if (!PDM.begin(1, EI_CLASSIFIER_FREQUENCY)) {
        ei_printf("Failed to start PDM!");
        microphone_inference_end();

        return false;
    }

    return true;
}

/**
 * @brief      Wait on new data
 *
 * @return     True when finished
 */
static bool microphone_inference_record(void)
{
    inference.buf_ready = 0;
    inference.buf_count = 0;

    while(inference.buf_ready == 0) {
        delay(10);
    }

    return true;
}

/**
 * Get raw audio signal data
 */
static int microphone_audio_signal_get_data(size_t offset, size_t length, float *out_ptr)
{
    numpy::int16_to_float(&inference.buffer[offset], out_ptr, length);

    return 0;
}

/**
 * @brief      Stop PDM and release buffers
 */
static void microphone_inference_end(void)
{
    PDM.end();
    free(inference.buffer);
}

#if !defined(EI_CLASSIFIER_SENSOR) || EI_CLASSIFIER_SENSOR != EI_CLASSIFIER_SENSOR_MICROPHONE
#error "Invalid model for current sensor."
#endif

Android App APK

This is the APK required to install the app on your Android phone

Credits

Stefan Tabakovski

Stefan Tabakovski

1 project • 0 followers
Lori Grum

Lori Grum

1 project • 0 followers
Jure Uršič

Jure Uršič

1 project • 0 followers
Mark Breznik

Mark Breznik

1 project • 0 followers
Luka Mali

Luka Mali

7 projects • 11 followers
Maker Pro, prototyping enthusiast, head of MakerLab, a lecturer at the University of Ljubljana, founder.

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