Pasco SPARKvue Data Collection

I must admit one of the features that most intrigued me when I got my first generation iPod Touch was the built in three axis accelerometer. I just thought it was very cool that with applications such as iSeismometer you could use the Touch as a data collection device.   Now, years later, the iPad has reached the point that it may well become a general purpose data collection and analysis tool.  In this posting I review SPARKvue, an app that allows one to collect data from the accelerometers, but also from a wide array of other Pasco sensors through a wireless interface.

The world of data collection, at least for high school and university physics classrooms, is largely dominated by two companies, PASCO and Vernier.  The physics classroom that I teach in has a bunch of iMacs, and for each a Pasco interface box and a variety of sensors that are used through the Pasco Data Studio software.  In this review I will cover the Pasco SPARKvue, a free app for data collection.   It can be used as is with the built-in accelerometers, or with a purchased bluetooth interface (called the PASPORT AirLink 2) to connect other PASCO PASPORT sensors (nearly 100 are available).  For this review I have only used it with the built-in accelerometers.

When you first start the SPARKvue app it seems rather bare.  I later realized this was deliberately to leave the graphical display as uncluttered as possible.  You double click the display to bring up the controls, that are mainly at the four corners, and a start stop button at the bottom of the display in the centre.

After you have worked with it an hour or so the application does grow on you.  To get started with a new experiment you press the + button on the top right.  This brings up a dialog box that allows you to name the experiment, add a description , and also specify what is to be measured, the units, sample rate and duration of sampling.  You can either have it sample continuously, or you can set it to sample for a duration such as 10 s.  If you have no interface box, the only options for what to measure are either the net acceleration, or the component in the x, y or z direction (see next paragraph).   For acceleration the units can be either in terms of standard m/s /s, or in terms of the acceleration due to gravity, g. You can have sampling rates up to 100 Hz, but it can also be used in very slow sampling mode, e.g. you could set it to take a sample every 50 minutes.  With the range of PASCO sensors, this wide range of easily set  sampling rates is a nice feature.

The standard display will be an xy line graph, and the program fills in the units.  One very nice feature is if you want it to auto scale so that the data fills most of the screen, you just tap with two fingers, and it does a great job!  After I got used to this, I like it a lot.  If you want finer control, you can pinch or drag to change the scaling or the range shown.  After using the program for an hour, I found the interface (while certainly more limiting in terms of features), for basic scaling of data much easier than the Pasco Data Studio software we use on the Macs.  You can add a second, third, etc. run by pressing the go/pause button that appears at the bottom of the graph.  On the left of the screen will appear a little box with 1,2,3,4 etc. and an arrow.  Pressing the arrow will give you the option of eliminating any sets you want just by selecting them and then delete.  You can also choose which to display in the same way.  You can have up to 99 data runs, although the screen would probably look pretty messy by then! There are three modes, the standard xy graph one that will be most useful, but also by sliding horizontally (in landscape mode) you can go to analog or digital meter settings.

The three axis accelerometer on the iPad (and iPhone, iPod touch) is oriented in the following way.  If you hold the iPad vertically in portrait mode so that the Home button is at the bottom,  then the x axis is horizontally (positive to the right), and the y axis is vertically.  The z axis is obviously perpendicular to the display.   It samples to 100 Hz, and I believe the maximum range is +/- 2g (I could not find this definitively anywhere).

The program has very limited abilities to analyze the data compared to the full Mac versions of PASCO software.  There is a summation symbol near the bottom right, and when you press that it will give you some basic information like the mean value, min, max, data point count and the standard deviation.  This may be useful if students do multiple runs of the same experiment.  A screen capture from my iPad showing a typical display is here, along with the data summary.

If you teach basic general relativity one nice feature is that if you simply measure the vertical component of the acceleration when it is fixed it will read (about) 9.8 m/s/s.  A very elegant demonstration that you can't tell the difference between being in a gravitational field, and an accelerated reference frame.  This also, using the mean and standard deviation features on a data set, allows your students to find g to rather good precision very simply.  

In most cases you will want to export the data for further manipulation.  There is a curved arrow icon on the bottom right that allows you to email the data in comma separated format for use in a spreadsheet program.  If (and only if) you have a single data run, the same button will export the data to Numbers (if you have it on your iPad) and it opens perfectly, with columns labelled.  Very slick!

The app will run on iPod touch (as long as running iOS 3.1.3 or later), iPhone or iPad (either original or 2).  It uses 1.6 MB of memory.

It is very nice that they gave this away in a useful mode even if you don't buy a wireless interface and any sensors.  Of course,  it would have been even nicer if they had built in use of the microphone for sound waveform display, or perhaps even the camera as a rough light sensor.  The software could also be more fully featured, e.g. allowing such simple manipulations as subtracting a constant value, or a simple fit.

Nevertheless, I am impressed with the app, and I am sure that additional versions will bring new features.  It offers exciting possibilities for having your students make measurements at the amusement park, in a moving vehicle (as long as they are not the driver!), or on the playground.   Overall I give it 8 (out of 10).  It's free, why not download it and give it a spin yourself?  If your students have used it for some innovative applications, why don't you (or they) leave a comment below.  I will update this if we get the bluetooth interface so I can try some of our sensors.

Note (2017):  There have been many changes to Pasco SPARKvue since this was written.  We will be doing a full review of the current version later in 2017.