Missing Y Data from Logger

Simon

Hello all,

I've been going through the tutorial and have made a simple logging app based on the C# UWP FreeFall App. The app connects to my MetaWearC and MetaMotionR boards. I can start logging, download the data, and process it, but I am getting all zero data for my Y accelerometer axis. ex.   { X: -0.331g, Y: 0.000g, Z: 0.054g}  

In rare cases I do get Y data, which makes me think it could be a race condition? The MetaBase Android app works and I'm getting Y data from it, so I know the boards are OK. I've tried various data rates and ranges - no effect. I'm sorry the code isn't very readable below, but I've outlined a simplified example of my order of operators:

var accelerometer = metawear.GetModule<IAccelerometerBmi160>();  //Access the acceleration module

accelerometer.Configure(odr: sensorRate, range: sensorRange); //Configure the sensor using float variables (usually 200, 4)

metawear.GetModule<ILogging>().Stop(); //Stop logging in case it's running from a previous attempt that crashed

await metawear.GetModule<ILogging>().ClearEntries(); //Clear any entries. I added an await here since I figured this takes time.

await accelerometer.Acceleration.AddRouteAsync(source =>source.Log((raw_data) => DataHandler(raw_data)); //setup my logger

accelerometer.Acceleration.Start(); //start the sensors for logging

accelerometer.Start();

metawear.GetModule<ILogging>().Start(); //start logging

//Allow time to elapse here

 metawear.GetModule<ILogging>().Stop(); //stop logging and sensors

accelerometer.Stop();

accelerometer.Acceleration.Stop();

 await metawear.GetModule<ILogging>().DownloadAsync(...); //async download

//Here's my data handler, which stores incoming data to a list for future parsing

        private void DataHandler(IData RawData)

        {

            AccelData.Add(RawData);

        }

//The data is parsed:

foreach (IData pt in AccelData){

                span = pt.Timestamp.Subtract(AccelData[0].Timestamp);

                elapsedtime = (double)span.TotalMilliseconds / 1000.0;

                System.Diagnostics.Debug.Write(pt.Value<MbientLab.MetaWear.Data.Acceleration>().ToString()); //No Y data

                PlotSeries[0].Points.Add(new DataPoint(elapsedtime, (double)pt.Value<MbientLab.MetaWear.Data.Acceleration>().X));

                PlotSeries[1].Points.Add(new DataPoint(elapsedtime, (double)pt.Value<MbientLab.MetaWear.Data.Acceleration>().Y));

                PlotSeries[2].Points.Add(new DataPoint(elapsedtime, (double)pt.Value<MbientLab.MetaWear.Data.Acceleration>().Z));

}

As you can probably tell, I'm a novice in UWP so any help is appreciated.

Thanks in advance.

Eric

Try streaming the data on your UWP app first to see if everything is properly working.

Simon

The streaming works no problem. I will run through my code again. Any ideas? 

Simon

I 'fixed' the problem. I changed which DownloadAsync method I used and I'm getting all the data:

I was used this:

await metawear.GetModule<ILogging>().DownloadAsync(100, async (nEntries, totalEntries) => await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>

            {

                System.Diagnostics.Debug.Write(String.Format("Progress Update= {0}/{1}\n", nEntries, totalEntries));

                Sensor.DownLoadProgress = (100.0 - 100.0 * (double)nEntries / ((double)totalEntries));

            })

The Dispatcher was there because 'Sensor' ViewModel was using INotifyPropertyChanged to update my view in real time to update the progress bar.

Now I just use this:

await metawear.GetModule<ILogging>().DownloadAsync();

No more fancy progress bar, but at least I have data now. 

Eric

Hrm, that doesn't make sense as both DownloadAsync functions call the same underlying function but with different default parameters.

This log and download code snippets are working fine with my board:

private async Task Start(IMetaWearBoard metawear) {
    var accelerometer = metawear.GetModule();

    accelerometer.Configure(odr: 200f, range: 4f);
    await accelerometer.Acceleration.AddRouteAsync(source => source.Log(data =>
        System.Diagnostics.Debug.WriteLine(string.Format("time: {0}, data: {1}", data.FormattedTimestamp, data.Value()))
    ));

    metawear.GetModule().Start();
    accelerometer.Acceleration.Start();
    accelerometer.Start();
}

private async Task Stop(IMetaWearBoard metawear) {
    var accelerometer = metawear.GetModule();

    accelerometer.Stop();
    accelerometer.Acceleration.Stop();

    var logging = metawear.GetModule();
    logging.Stop();
    await logging.DownloadAsync(100, (nEntries, totalEntries) => System.Diagnostics.Debug.WriteLine(String.Format("Progress Update= {0}/{1}", nEntries, totalEntries)));
}