I can not send data with writeCharacteristics

[ltobiomynuvola]

Hello everybody,

I have a bluethooth device (HM10) that receives an 'a' as a test, but I do not know how to send this string as an array buffer.

The device connects, the problem is the sending of this data

This is my code:

`
var service = evothings.ble.getService(app.device, app.SERVICE_UUID);
var characteristic = evothings.ble.getCharacteristic(service, app.CHARACTERISTIC_UUID);
app.display(JSON.stringify(characteristic));

    var data = new Uint8Array(1);
    data[0] = 'a';
    evothings.ble.writeCharacteristic(
    app.device,
    characteristic,
    data, // Buffer view with data to write
    function()
    {
        app.display('characteristic written');
    },
    function(errorCode)
    {
        app.display('writeCharacteristic error: ' + errorCode);
    });

`

NOTE:

I have also sent:

'a' binary
var data = new Uint8Array(8);
data[0] = '0';
data[1] = '1';
data[2] = '1';
data[3] = '0';
data[4] = '0';
data[5] = '0';
data[6] = '0';
data[7] = '1';

'a' Hexa
var data = new Uint8Array(2);
data[0] = '6';
data[1] = '1';