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Discussion Starter #1
Looking at getting a tablet very soon. They are available with gps antennas built in. Anybody know about gps based basic daq apps? I know they are available and powerful enough to be worth having on ios; what about android?
 

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I've played with trackmaster a few times. Awesome app and constantly being updated. Lap times seem pretty much spot on when comparing my video with the app. I've never tried using the Apple stuff so I can't compare, but it's basically the only data acquisition available for Android (haven't looked in a while though). Has GPS, driving lines, accelerometer, etc.

It does use google maps for you to set sector areas so I'm thinking you would definitely need some sort of data connection. Don't think wifi would be enough at the tracks. Autocross maybe.
 

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I use Harry's Laptimer Pro on my iPhone to do the GPS, OBD2, Accelerometer, and HD Video. It overlays everything together in one video file at the end. Lots of guys in my region use it for autocross. We even suggested to Harry to put n an Autocross feature, and now it is there. I don't think it works on Android though.
 

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Discussion Starter #4
trackmaster can use an external bluetooth gps antenna, I'm presuming it would play nice with a 20 hz unit, and work much better than a $500 maxqdata unit from 5 years ago.... Now I'm looking for a bluetooth tablet instead of a gps tablet.

you mean you'd need wifi to register the gps location data against a real map, right? I'd be ok with not having that on location. For day of event data, I'd most be interested in segment time comparison between runs at autocross, and g-curves while cornering between different drivers.
 

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trackmaster can use an external bluetooth gps antenna, I'm presuming it would play nice with a 20 hz unit, and work much better than a $500 maxqdata unit from 5 years ago.... Now I'm looking for a bluetooth tablet instead of a gps tablet.

you mean you'd need wifi to register the gps location data against a real map, right? I'd be ok with not having that on location. For day of event data, I'd most be interested in segment time comparison between runs at autocross, and g-curves while cornering between different drivers.
Yeah you would need some kind of connection to load google maps but I guess you wouldn't need that for autocross. I could be wrong but from what I remember you can walk the course with your tablet/phone and then set a segment location based on your current position.
 

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I use trackmaster with an external 5hz GPS unit. Works fine. I think the phone processors are not fast enough to handle high hz GPS units. I have an HTC EVO phone. It won't work with 10hz external GPS.

Here what trackmaster said about that:
A question that comes up a lot when using an external bluetooth GPS with Trackmaster is whether to use 5 Hz or 10 Hz GPS. With Trackmaster it's a misconception that 10 Hz is better than 5 Hz. In fact, it can be worse. If your device does not have a powerful processor that can handle the 10 Hz rate, you will have data logging issues. Data will be dropped or delayed. Only the latest devices with very powerful processors (1GHz+) can handle the higher rate. Also keep in mind that you are generating much more data with 10 Hz. So post-processing the data will take longer for analysis and export.

10 Hz is NOT more accurate than 5 Hz. Trackmaster interpolates data. This allows it to be very accurate. Some people attempt an accuracy calculation based on the refresh rate .2 secs (5Hz) and .1 secs (10Hz). Because Trackmaster interpolates data, this calculation is incorrect.

Unless you have a specific need for 10 Hz and have a powerful device, I recommend using a 5 Hz GPS over 10 Hz.

If you already have a 10 Hz GPS and are experiencing issues, you may be able to reprogram the GPS for a lower rate. The QStarz GPS allows you to do this.

Jeff
However the most important part for me is to have the proper software to analyze the data. In that department the trackmaster is still lacking.

AIM now makes a nice GPS based lap timer that is only $399. Aim SOLO. I am looking a buying one of these. It has a 3-axis G sensor and 10hz gps.

I also used to own a Racelogic Performance box. Easy to install use and the software is great. It was easy to take from car to car and compare to other drivers with the performancebox. Used 10hz update rate. Price is not bad at $499. I bought mine for $450 during a group buy.
 

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I use trackmaster with an external 5hz GPS unit. Works fine. I think the phone processors are not fast enough to handle high hz GPS units. I have an HTC EVO phone. It won't work with 10hz external GPS.

Here what trackmaster said about that:


However the most important part for me is to have the proper software to analyze the data. In that department the trackmaster is still lacking.

AIM now makes a nice GPS based lap timer that is only $399. Aim SOLO. I am looking a buying one of these. It has a 3-axis G sensor and 10hz gps.

I also used to own a Racelogic Performance box. Easy to install use and the software is great. It was easy to take from car to car and compare to other drivers with the performancebox. Used 10hz update rate. Price is not bad at $499. I bought mine for $450 during a group buy.
I looked at the data points on their informational stuff on the website, and it looks like there isn't that much data being collected, at least a 1hz. Still, if I'm buying a tablet anyway, it is probably worth $45 or whatever for a bluetooth gps antenna and the app... It says it exports to excel. Have you done that? Do you think you could send me an excel file to play around with? I'm pretty handy with excel, and might, if the data looks good (for example, does it time stamp each data point so the data can be correlated with other data, like say obd2 data?) I might be able to write something up to crunch the data in some useful ways that could be done at an event....
 

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I can send an excel file from a run session with 5hz external GPS. Need an E-mail address.

I haven't really looked at the data. I have just used it as a lap time.

Also if your phone rings trackmaster freezes. One of the disadvantages of using a phone as a lap timer.
 

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Discussion Starter #10
I can send an excel file from a run session with 5hz external GPS. Need an E-mail address.

I haven't really looked at the data. I have just used it as a lap time.

Also if your phone rings trackmaster freezes. One of the disadvantages of using a phone as a lap timer.
PM sent. I live in an area where there is only one carrier that gets reception reliably, and I can't justify the cost of one of their phone data plans, so I'll definitely be running it on an android tablet with wifi only if I go this route. It is still unclear to me if you can really use this app without a live connection to google earth... If not, well, here's hoping the developers keep developing :D
 

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I use google earth to set split markers but its optional. I think you can also import the split data from a computer.
 

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I can send an excel file from a run session with 5hz external GPS. Need an E-mail address.

I haven't really looked at the data. I have just used it as a lap time.

Also if your phone rings trackmaster freezes. One of the disadvantages of using a phone as a lap timer.
Thank you for sending the file. It gives me a good idea of what I'd be getting. Just enough to be tempting, but no where near what the hardware is capable of. I notice the file you sent me is only 1hz. at first I thought it was just the accelerometer data, but it is the gps too. Did you know you were only getting 1hz data for that set (error is which file you sent or something), or maybe does the software in its own analysis provide interpolated 5 hz so you think you are getting more than you are?
 

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I am not sure which session was 1hz and which 5hz. I used two different phones and multiple track days. I did some of them with the external GPS. Does it state in the file specifically the hz so I can look at all the sessions?
 

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Discussion Starter #14
I am not sure which session was 1hz and which 5hz. I used two different phones and multiple track days. I did some of them with the external GPS. Does it state in the file specifically the hz so I can look at all the sessions?
I find nothing that explicitly states the sample rate anywhere. The file size would be substantially larger. Failing that, you can go to any of the "lap X" tabs in the excel file and look at the data. If the time stamps are roughly 1 second apart, you have 1 hz. if there are 5 per second, it is about 5 hz, and so on.
 
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