Freematics Forum

Hey All,

(repost)

I recently purchased a Freematics Vehicle Data Logger. We are measuring fuel consumption for the Technical University of Eindhoven (The Netherlands) and are very happy with the options from the Freematics.
We have gathered a lot of data in the mean time but unfortunately we can't understand the data as it is in a different format as stated in the tutorials and documentation. A sample data below:

50 20 717 -44 -766
0 21 -7 1 0
0 22 -574 1039 653
50 20 721 -34 -770
0 21 -5 2 0
0 22 450 -433 -308
51 20 727 -44 -758
0 21 -6 1 -2
0 22 1858 1039 -1523
50 20 723 -45 -762
0 21 -7 3 -1
0 22 770 783 1677


Is there a way to read this? What am i seeing?
I am very pleased if someone could help us!

Thanks in advance

Mark

Well, I'm no expert, but I think it's reading only the integrated accelerometer+gyroscope+compass (the data from the MPU9150 chip):

The first number from each line is the milliseconds passed from the previous Reading.
The second would show the number of the PID being logged. The MPU is set up so that the accelerometer reads as PID 0x20, gyro as 0x21 and compass as 0x22.
Naturally, the next three numbers on each line show the values measured on each of the axis of the device in question.

thanks!

that seems to be logical. so i'll integrate the data, that should give some speed plots we're looking for.
I think i need to put a different sketch on it. i think i can figure out how with the detailed info on this site.

thanks again

Mark

The datalogger.h file contains all the information. The first column is the time elapsed in ms. The second is the PID # (0x20, 0x21, 0x22 for accelerometer, gyroscope and compass). The following 3 numbers are the data.

Hello markiempje.

Have you find any method to generate a chart from the data?

Regards,
Jesus.

I have some poorly written windows forms code that puts the information into a graph form. I also have the accelerometer setup to display as a little bubble in a box that moves around and gets bigger or smaller.

You might be able to plot something with excel's graphing functions. pull everything 20/21/22 and show its points accordingly.

protomor wrote:
> I have some poorly written windows forms code that puts the information
> into a graph form. I also have the accelerometer setup to display as a
> little bubble in a box that moves around and gets bigger or smaller.
>
> You might be able to plot something with excel's graphing functions. pull
> everything 20/21/22 and show its points accordingly.

Hello protomor.
Would you share it? I really need a form to obtain a graph of the captured data, but on excel, with the data format used it seems very complicated.
Can you send me a private message? The system does not avoid me to send yet.
Thank you in advance.
Jesas

If you have any way to interpret the data into a graph would it be possible for you to share it, I'm using this as a university project and i am struggling to find a way to view the data in a comprehensive way

Give me a few days to finish some stuff and make my code a little more pretty. I've just been coding it off the top of my head so it isn't very efficient and it's just one giant file. I can't guarantee it will load logs without tiny modifications. It's written pretty specifically for me.

Requires VS 2012 and windows. Although I guess I could release just the exe?

Well here's a link to just the EXE by itself. https://drive.google.com/file/d/0ByBda7 ... sp=sharing

File->Open and select your CSV file. I haven't tested the "save as torque" option but it should theoretically still work. Right now it averages between the farthest points instead of tweening. So far it hasn't been an issue but the GPS plots are a bit off from time to time (brakes in the line).

But basically, the top half is for basic log information and the bottom half is specifically for the GPS outputs. You can click on the chart to view that plot's specific data. The funny gray box in the middle right is a "bubble" output of the GPS. There's no factoring for up/down or whatever so it's not useful outside of a cool graphic. Click part of the graph and hit play to replay the log at 2x speed. You can click/select a section of the chart to zoom in. The zoom out button zooms out but also the bottom left of the chart has a zoom out button that you can't really see. There's also a scroll bar down there if you zoom in.

The google map output splices the selected data to the left into 7 color segments. Red is the lowest value and there's a pink for the highest. Eventually you'll pick your own colors. Also, as it renders the google map on screen, it's dumping "output.kml" into the working folder. At least I think it still is. You can load that on google earth if you'd like.

So far, the logger assumes you have GPS and accelerometer data with the PID outputs. I think it will break otherwise. I'm not sure.

Suggestions welcome.