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January 12, 2006

GPS Logger arrives

My G2Extreme came today. It's pretty small, maybe 4 x 3 x 1. The unit itself needs to be firmly attached and needs to really be pointing absolutely straight for the accelerometers to read 0 when you're in a straight line. For now, I used some bunge cords to strap it to my center console door.

The GPS antenna is very sensitive, it picked up 6 satellites inside my house on the kitchen counter top. I got 9 on the roof of the car. The antenna is supposed to be mounted on the highest part of the car, the center of the roof usually. I have a sunroof and opened it slight so I could put the antenna in the center of the sun roof. It's magnetic. No idea whether it scratches yet. This position worked well tonight but I'll probably make a bracket that I can attach to the harness bar and bolt everything to that.

I reckon the antenna will work fine inside the car but worst case, it goes back on the sun roof.


The dash is actually a distraction. You can't drive and keep glancing at it, you'll kill someone. I disconnected it. So, I just have the unit itself and the antenna in the car.

The unit itself is pretty clever. It finds GPS satellites very quickly. It syncs up for me well under 10 seconds. It records automatically when the car starts moving and stops 30 seconds after the car stops moving. The 128MB memory basically can log 30 hours of data but I reckon at an event, I'll just forget about it and drive the car. When I get back to the hotel, I'll look at the days data.

It knows your speed from the 4hz GPS unit. I discovered my speedo is 4.8mph too high. Indicated 65 at 60.2mph.

The unit can be wired to the RPM somehow, theres a wire for it and if you do that then it can figure out the gear you're in by comparing the RPMs to the speed. You can tell it the gearing so that it can figure this out using the RPMs.

It has real 100Hz accelerometers in it for long and lat acceleration.

So basically, you put it in the car and forget about it. No buttons etc. I went and drove a couple of legal laps around IBMs car park today and then drove home. The map is pretty cool and it uses the lat G to automatically draw corners. It nearly gets it right and it's easy to fix it.

The software with it is ok, I'd say, a lot of useful features are missing. For example, you can't export a GIF/JPG of the map or a zoomed portion of the map. I'm probably write something to solve that problem or maybe racepak will fix it for me.

Thats about as far as I've gotten with it. Ease of use wise, this looks real nice. I don't think I'll bother with the dash display. It would violate my drivers ed insurance anyway if the car was timed at the event. I can check how I did at the hotel where it's legal. Some schools are already using this approach to use this device for education without breaking the insurance rules. I'll be leaving the dash at home.

We should be able to use it for some cool graphics for Trackpedia though. Just need to get to the tracks again.

January 12, 2006 | Permalink


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