Android : JSON data POST to server

I want to POST accelerometer JSON data to a server. acc is acceleration variable.

acc.x represents accelerometer x axis valye
acc.y (same) y axis value
acc.z (same) z axis value

This is the function which POST acceleration data as JSON format.

var acc;

function request() {
    alert("Entering request function");
    alert(acc.x);
    alert(acc.y);
    alert(acc.z);
    var fromData = json; //Here to put JSON format that is given in next codeblock
    alert(JSON.stringify(fromData));

    var fromDatan = JSON.stringify(fromData);
    alert(fromDatan);
    $.ajax({
        url: "abc.com",
        headers: {
            "x-api-key": "abcd=",
            "content-type": "application/json"
        },
        type: "POST",
        data: fromDatan,

        success: function(fromData, status, jqXHR) {
            alert(JSON.stringify(fromData));
        },

        error: function(jqXHR, status) {
            alert(JSON.stringify(jqXHR));
        }
    });
    return false;

};

Now the server expects this JSON:

{
    "version": "1.0.1",
    "observations": [{
        "sensor": "", //sensor ID to be put manually or by form
        "record": [{
            "starttime": "1-JAN-2014 15:30:00 IST",
            "output": [{
                "name": "", //in "", Accelerometer_X
                "value": "" //in "" acc.x
            }, {
                "name": "", //in "", Accelerometer_Y
                "value": "" //in "" acc.y
            }, {
                "name": "", //in "", Accelerometer_Z
                "value": "" //in "" acc.z
            }]
        }]
    }]
}

Now, in previous codeblock, in var formData, I have to assign this JSON with accelerometer variables mentioned above. But as I am new to these things o I am unable to guess how to do that. So please help me out :)

After assigning it in formData, it is expected that it will take accelerometer value and POST to server. in 1st code, to debug I added alert of x, y, z values and it is giving perfectly accelerometer data. Now I need to POST. So please review code and suggest please :)