Zephyr TLM Eddystone Beacon

[gavo]

Hi There,

New to the Forum and I have started to use the Zephyr RTOS in Visual Studio Code:

I am trying to get an Eddystone Beacon based off the nRF528323 and I am transmitting the URL Frame and the TLM frame.

I have the URL Eddystone Beacon working sending Data to the nRF Connect AP but somehow I can't seem to see the TLM Data and i just need to display the battery data. I have tried this plenty of different ways but i simply cannot see the TLM data. Any help would be great appreciated!, below is the code I am using and the prj.conf file as well as the overlay file

#include <bluetooth/bluetooth.h>
#include <bluetooth/hci.h>
#include <drivers/adc.h>
#include <hal/nrf_saadc.h>
#include <drivers/gpio.h>
#include <zephyr.h>
#include <nrf.h>
#include <logging/log.h>
#include <sys/byteorder.h>


#define ADC_RESOLUTION 10
#define ADC_GAIN ADC_GAIN_1_4
#define BATTERY_CHANNEL_ID 0
#define BATTERY_INPUT NRF_SAADC_INPUT_AIN0
#define LED_PORT DT_LABEL(DT_NODELABEL(gpio0)) // Assuming LEDs are connected to GPIO0
#define LED_PIN 15 // Pin number for the first LED
#define LED_PIN_2 18 // Pin number for the second LED

static uint16_t adc_sample_buffer;
static const struct device *led_dev;
static const struct device *adc_dev;

static const struct adc_channel_cfg my_channel_cfg = {
    .gain = ADC_GAIN,
    .reference = ADC_REF_INTERNAL,
    .acquisition_time = ADC_ACQ_TIME_DEFAULT,
    .channel_id = BATTERY_CHANNEL_ID,
    .input_positive = BATTERY_INPUT,
};

static const struct bt_data ad[] = {
    BT_DATA_BYTES(BT_DATA_UUID16_ALL, 0xAA, 0xFE), // Eddystone service UUID
    BT_DATA_BYTES(BT_DATA_SVC_DATA16,
    0xAA, 0xFE,   // Eddystone service UUID
    0x10,         // Eddystone-URL frame type
    0xF8,         // Calibrated Tx power at 0m
    0x01,         // URL Scheme 'http://www.'
    's', 't', 'r', 'a', 't', 'a', '.', 'c', 'o', 'm'), // URL

};

static int led_init(void) {
    led_dev = device_get_binding(LED_PORT);
    if (!led_dev) {
        printk("LED device not found\n");
        return -ENODEV;
    }

    int err = gpio_pin_configure(led_dev, LED_PIN, GPIO_OUTPUT_ACTIVE);
    if (err) {
        printk("Failed to configure LED pin (err %d)\n", err);
        return err;
    }

    err = gpio_pin_configure(led_dev, LED_PIN_2, GPIO_OUTPUT_ACTIVE);
    if (err) {
        printk("Failed to configure LED pin 2 (err %d)\n", err);
        return err;
    }

    return 0;
}

static int adc_init(void) {
    adc_dev = device_get_binding(DT_LABEL(DT_NODELABEL(adc)));
    if (!adc_dev) {
        printk("ADC device not found\n");
        return -ENODEV;
    }

    int err = adc_channel_setup(adc_dev, &my_channel_cfg);
    if (err) {
        printk("Failed to set up ADC channel (err %d)\n", err);
        return err;
    }

    return 0;
}

static uint16_t read_battery_voltage(void) {
    if (!adc_dev) {
        printk("ADC device not found\n");
        return 0;
    }

    const struct adc_sequence sequence = {
        .channels = BIT(my_channel_cfg.channel_id),
        .buffer = &adc_sample_buffer,
        .buffer_size = sizeof(adc_sample_buffer),
        .resolution = ADC_RESOLUTION,
    };

    int err = adc_read(adc_dev, &sequence);
    if (err) {
        printk("Failed to read ADC (err %d)\n", err);
        return 0;
    }

    return (adc_sample_buffer * 3300) / (1 << ADC_RESOLUTION)* (2.979 / 3.296);
   // return (adc_sample_buffer * 3300 * 4) / (1 << ADC_RESOLUTION); // Convert to millivolts

}

static void update_tlm_data(uint16_t battery_voltage) {
    uint8_t tlm_data[] = {
        // Eddystone TLM header
        0xAA, 0xFE,                   // Eddystone UUID
        0x20,                         // TLM frame type
        0x00,                         // Version
        0x00, 0x00,                   // Battery voltage (placeholder)
        0x00, 0x00,                   // Temperature (placeholder)
        0x00, 0x00, 0x00, 0x00,       // PDU count (placeholder)
        0x00, 0x00, 0x00, 0x00        // Time since boot (placeholder)
    };

    // Convert battery voltage to fixed point format and place in advertising packet
    sys_put_be16(battery_voltage, &tlm_data[4]);

    // Update the advertising data
    const struct bt_data ad_tlm[] = {
        BT_DATA(BT_DATA_MANUFACTURER_DATA, tlm_data, sizeof(tlm_data)),
    };

    int err = bt_le_adv_update_data(ad_tlm, ARRAY_SIZE(ad_tlm), NULL, 0);
    if (err) {
        printk("Failed to update advertising data (err %d)\n", err);
    }
}

void print_advertising_data(const struct bt_data *ad, size_t ad_len) {
    printk("Advertising Data:\n");
    for (size_t i = 0; i < ad_len; i++) {
        printk("Type: %d, Data: ", ad[i].type);
        for (size_t j = 0; j < ad[i].data_len; j++) {
            printk("%02X ", ad[i].data[j]);
        }
        printk("\n");
    }
}



void bt_ready(int err) {
    if (err) {
        printk("Bluetooth init failed (err %d)\n", err);
        return;
    }

    printk("Bluetooth initialized\n");

    if (led_init()) {
        printk("LED init failed\n");
        return;
    }

    if (adc_init()) {
        printk("ADC init failed\n");
        return;
    }

    const struct bt_le_adv_param adv_params = {
        .options = BT_LE_ADV_OPT_CONNECTABLE,
        .interval_min = BT_GAP_ADV_FAST_INT_MIN_2,
        .interval_max = BT_GAP_ADV_FAST_INT_MAX_2,
    };


    // Print advertising data for debugging
    print_advertising_data(ad, ARRAY_SIZE(ad));

    // Start advertising
    err = bt_le_adv_start(&adv_params, ad, ARRAY_SIZE(ad), NULL, 0);
    if (err) {
        printk("Failed to start advertising (err %d)\n", err);
        return;
    }

    printk("Advertising started\n");

    while (1) {
        // Read battery voltage and update TLM data
        uint16_t battery_voltage = read_battery_voltage();
        printk("Battery Voltage: %d mV\n", battery_voltage);
        update_tlm_data(battery_voltage);

        // Stop advertising
        bt_le_adv_stop();
        printk("Advertising stopped\n");
        
        // Wait a bit to ensure advertising has stopped
        k_sleep(K_SECONDS(1));

        // Set LED and start advertising Eddystone-URL
        gpio_pin_set(led_dev, LED_PIN, 1); // Turn on LED
        err = bt_le_adv_start(&adv_params, ad, ARRAY_SIZE(ad), NULL, 0);
        if (err) {
            printk("Advertising Eddystone-URL failed to start (err %d)\n", err);
            gpio_pin_set(led_dev, LED_PIN, 0); // Turn off LED if advertising fails
        } else {
            printk("Eddystone URL Advertising started\n");
            k_sleep(K_SECONDS(10)); // Adjust as needed
        }

        // Ensure LED is turned off
        gpio_pin_set(led_dev, LED_PIN, 0);
        
        // Wait a bit before next iteration
        k_sleep(K_SECONDS(10));
    }
}


void main(void) {
    int err = bt_enable(bt_ready);
    if (err) {
        printk("Bluetooth init failed (err %d)\n", err);
        return;
    }
}
  

Below is my prj.conf file:

# General Bluetooth options
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_BROADCASTER=y
CONFIG_BT_DEVICE_NAME_MAX=30
CONFIG_BT_DEVICE_NAME="GAVO"
CONFIG_ADC=y
CONFIG_SERIAL=y
CONFIG_UART_CONSOLE=y
CONFIG_LOG=y
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_BT_RX_STACK_SIZE=2048
CONFIG_BT_DEBUG_LOG=y
CONFIG_BT_L2CAP_DYNAMIC_CHANNEL=y
CONFIG_BT_SETTINGS=y
CONFIG_BT_GATT_DYNAMIC_DB=y
CONFIG_BT_GATT_SERVICE_CHANGED=y

# Security Manager Protocol (SMP) for Bluetooth
CONFIG_BT_SMP=y  # Ensure this is set if BT_L2CAP_DYNAMIC_CHANNEL is used

# Logging options
CONFIG_LOG=y

# Bluetooth stack sizes
CONFIG_BT_RX_STACK_SIZE=2048
CONFIG_BT_HCI_TX_STACK_SIZE_WITH_PROMPT=y

and my overlay file is also below:

&uart0 {
    current-speed = <115200>;
    status = "okay";
    tx-pin = <6>;
    rx-pin = <8>;
};

[Brian Kim]

Hello Gavin,

Please allow me two questions for better support.

-. Eddystone is deprecated since 2010 by Google. Are you aware of this and do you still want to use it?

-. According to your description, it sounds like that TLM frame is not shown on the scanner side. Is this your main issue?

  I just ran the Zephyr Eddystone example and see it works without any issue. Could you correct me if I missed your point?

//Brian

[gavo]

Hi Brian,

Do you have a link to the example code please? Yes my issue is the TLM data not showing up in the scanner side

[Brian Kim]

Hello Gavo,

Sorry for not noticing this reopen.Please allow a quick question?

Q1. I believe you could see TLM data using the example I shared before? correct?

Q2. If yes, are you struggling to apply it to your application and this is your current issue?

Best regards,

Brian

[gavo]

Hi Brian,

No problems at all, I used the example and all I could see what what I attached, still can't see the TLM Data even though I used the original Zephyr Example code

[Brian Kim]

That's weird. There must be something wrong then.

I will try again with the example code and the application you are using.

What mobile application do you use for this?

[gavo]

I am using the nrF Connect Application, version 2.6.7

[Brian Kim]

Thanks. Initially, I verified it with the application(nRF Connect 4.26.1) for Android. Have you tried it?

I just tested it on Apple phone and confirmed it's almost same as yours. I am internally checking why this is not parsed and will keep you updated soon.

However, now that the example is already there, if the purpose is to see if it's TLM type and validify of the data on your beacon, you can verify it on Android. 

If not, could you tell me what we can assist for you?

//Brian

[gavo]

Ah that might be the issue, I have been using an iPhone, let me try on an Android Device...

[gavo]

Hi Brian,

Attached is what I am seeing on my Android Tablet

The Raw Data 0x0201040303AAFE1416AAFE1000007A657068797270726F6A65637408 does not show any of the TLM Data,

My tablet is very old I will try a new Android Device tomorrow

[Brian Kim]

Hello Gavin,

It will show like that at first, but as I told you before, TLM will be shown up after idle timeout defined 30seconds. Could you wait and let me know the result?

//Brian

[gavo]

Hi Brian,

I did wait but still nothing....I am trying another piece of code and will advise

[Brian Kim]

Hello Gavin,

No problem. I can send the  verified binary of the example for you. If you have any Nordic DK, just let me know what it is(nRF52DK or nRF52840DK, or anything else)and I can share the binary. (or you can send the binary for any of DKs the other way around and then I can verify here..)

//Brian