Decode Help

tknman0700 · September 29, 2020, 9:15pm

We are using javascript and trying to understand how to get usable information from the hex after we unpack it. We tried https://reelyactive.github.io/advlib/ but it seems to not properly parse the packet. Any direction you can offer as to how to get usable information from the hex is greatly appreciated.

aprilpea · September 30, 2020, 2:16am

We wrote a tool ble viewer which is written in javascript. You should use msgpack library to decode the package first.

please see the code

github.com

AprilBrother/ble-viewer/blob/master/renderer.js#L61


    console.log("connected")
    client.subscribe(topic)
})

$('#container').html(loadTemplate("devices-cont", null));
client.on('message', function (topic, message) {
    if (!is_fetch) {
        return;
    }

    var data = msgpack.decode(message);
    if (typeof data.devices == "undefined") {
        return;
    }
    data.cnt = data.devices.length;

    var t, filter = $('#mac-filter').val();
    if (filter.length && !(filter.length % 2)) {
        filter = filter.toUpperCase().match(/.{2}/g).join(' ');
        for(var i = 0; i < data.devices.length; i++) {
            t = toFormatHex(data.devices[i]);

did you get the BLE advertising data from the packet?

tknman0700 · September 30, 2020, 3:35pm

we have the msgpack part handled and we have the advertising binary but we dont know how to translate that to data that is useful to us - readable text.

tknman0700 · September 30, 2020, 3:42pm

trying to make sure we can read the data off the advertising packet including the mac of the beacon / bluetooth device we are seeing.

tknman0700 · October 2, 2020, 2:17pm

Anyone able to help? we have the data unpacked but trying to see if there are any JS libraries to help with decoding the HEX data into readable text?

tknman0700 · October 6, 2020, 4:44pm

is there a better way to get support?

aprilpea · October 9, 2020, 2:35am

There’s no exists js library to parse whole data. But you can get RSSI and mac address from the data first. see the packet format.

Do you want get the iBeacon format? Please check the link

I will try to find javascript library to parse BLE advertising data today

aprilpea · October 9, 2020, 2:43am

Please check bleadvertise and ble-packet-parser

tknman0700 · October 9, 2020, 6:44pm

ok thank you we will look at this - we struggled to get them to parse properly. We are working with ibeacon. Do you have any working code samples that would allow us to get UUID, battery, rssi, mac from the beacon.

aprilpea · October 10, 2020, 2:59am

Please also check node-beacon-scanner’s parser. It supports iBeacon protocol. You may change a little code to match your requirements.