Browan Object Locator and payload formatter

End Devices (Nodes) Hardware
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1

Hi everyone,

has anyone managed to do an uplink payload formatter on TTN for the Browan Object Locator?

I have used this but I am not getting correct location information:

function Decoder(bytes, port) {
var params = {
“bytes”: bytes
};
bytes = bytes.slice(bytes.length-11);
if ((bytes[0] & 0x8) === 0) {
params.gnss_fix = true;
} else {
params.gnss_fix = false;
}
// Mask off enf of temp byte, RFU
temp = bytes[2] & 0x7f;
acc = bytes[10] >> 5;
acc = Math.pow(2, parseInt(acc) + 2);
// Mask off end of accuracy byte, so lon doesn’t get affected
bytes[10] &= 0x1f;
if ((bytes[10] & (1 << 4)) !== 0) {
bytes[10] |= 0xe0;
}
// Mask off end of lat byte, RFU
bytes[6] &= 0x0f;
lat = bytes[6] << 24 | bytes[5] << 16 | bytes[4] << 8 | bytes[3];
lon = bytes[10] << 24 | bytes[9] << 16 | bytes[8] << 8 | bytes[7];
battery = bytes[1];
capacity = battery >> 4;
voltage = battery & 0x0f;
params.latitude = lat/1000000;
params.longitude = lon/1000000;
params.accuracy = acc;
params.temperature = temp - 32;
params.capacity = (capacity / 15) * 100;
params.voltage = (25 + voltage)/10;
params.port=port;
return params;
}

2

Hi, Did you manage to get the browan object locater installed? (Interrested because I just bought one and is on it’s way. I am now preparing on how to get it added to ttn)

3

Were you ever able to get an uplink formatter to work? I’ve been unsuccessful as well.

4

Are they not GNSS devices? So then you need a GNSS solver.

Have you tried

https://github.com/dasdigidings/the_things_stack_v3_tabs_decoder
1 Like
5

Try this:

function Decoder(bytes, port) {
    // Initialize params object with bytes
    var params = {
        "bytes": bytes
    };
    
    // Slice the last 11 bytes from the array
    bytes = bytes.slice(bytes.length - 11);
    
    // Check GNSS fix status
    if ((bytes[0] & 0x8) === 0) {
        params.gnss_fix = true;
    } else {
        params.gnss_fix = false;
    }

    // Extract and mask temperature byte
    var temp = bytes[2] & 0x7f;

    // Extract and compute accuracy
    var acc = bytes[10] >> 5;
    acc = Math.pow(2, parseInt(acc) + 2);

    // Mask off end of accuracy byte, so lon doesn’t get affected
    bytes[10] &= 0x1f;
    if ((bytes[10] & (1 << 4)) !== 0) {
        bytes[10] |= 0xe0;
    }

    // Mask off end of latitude byte
    bytes[6] &= 0x0f;

    // Combine bytes to form latitude and longitude
    var lat = (bytes[6] << 24) | (bytes[5] << 16) | (bytes[4] << 8) | bytes[3];
    var lon = (bytes[10] << 24) | (bytes[9] << 16) | (bytes[8] << 8) | bytes[7];

    // Extract battery information
    var battery = bytes[1];
    var capacity = battery >> 4;
    var voltage = battery & 0x0f;

    // Populate params with extracted and computed values
    params.latitude = lat / 1000000;
    params.longitude = lon / 1000000;
    params.accuracy = acc;
    params.temperature = temp - 32;
    params.capacity = (capacity / 15) * 100;
    params.voltage = (25 + voltage) / 10;
    params.port = port;

    // Return the final params object
    return params;
}