Harry's GPS Suite Forum

Hi,

I was wondering if there is a setting to read G-force measurements from the bluetooth GPS device vs the iPhone itself?

Thank you!
Zachary Wong

Hi,

GPS and accelerator are different sensors. While the iPhone has both (and some more), a GPS mouse is GPS only. So there is no alternative for measured forces. What you can do however, is calculating the forces from the GPS plot. This is pretty well implemented for LapTimer and available in Lap Details. Press the 'Calculate' button to overwrite measured values with calculated values. This is especially useful for motorcycle drivers as lateral acceleration is zero here.

- Harry

my apologies, i wasn't clear. my gps device actually can measure GPS and g-forces so was hoping i wouldn't have to mount my iphone and store it somewhere else in the car (securely of course) rather than window mounting it. it's not a deal killer at all, just thought there might be a setting i was missing.

thank you!
Zach

Hi,

Please let me know what device this is (I'm not aware of a BT GPS including acceleration measures) and I will check if I can support it.

- Harry

Hi Harry,

The BT GPS i am using is the QStarz BT-Q1000eX (http://www.qstarz.com/Products/GPS%20Pr ... EXQR-F.htm).

I have a fellow racer using a Wintec G-Rays (http://www.semsons.com/wigiwblgpsre.html) that also measures G-forces, unless in both cases we are being fooled and they are calculating the G-forces from GPS data as you mentioned.

Thanks!
Zach

Looking into the description I doubt they measure g forces.

- Harry

My Porsche Cayman S 981 has a dashboard G meter, which is one of several displays available.

The source of these data, I believe, is the Event Data Recorder.

G forces are used in calculating the force needed for airbag deployment. This is the case for most recently built cars sold in the United States.

Perhaps these data are available via the OBD port.

No, oddly not using standard PIDs. Acceleration sensors are available on all modern cars, but the data is kept secret or need to be licensed for a lot of money.

- Harry

If you use a VBOX Sport, the .vbo file recorded on the internal SD card will have speed, lateral and lineal acceleration. But it's calculated from the GPS data, not measured with accelerometers. Racelogic sells an IMU unit that measures acceleration and rotation rates for three axes, but it only attaches to a VBOX3i. They don't list a price for either, but I'd bet it's on the order of $5,000 US for both. It's really great if price is no object. It drastically reduces the noise in the speed and acceleration data and gives you yaw, pitch and roll as well.