I'm not sure if any of you are familiar with the 'ol gtech. I dont even know if they produce them anymore. However, I know it used an accelerometer to measure 1/4 miles times, 0-60mph, i think a rough estimate of HP, and some other crap. My thought was, why not use one of these new phones with an accelerometer and see about recreating that. Unfortunately, I dont have one of those phones (mogul and a curve 8330), nor a gtech, but I bet someone that's into cars has one or the other, maybe both.
Just a thought, and if its the wrong forum, my apologies.
--------- New Post Merged on 27/8/2009 at 03:02:11 --------
Quote:
Acceleration:
At the heart of G-TECH/Pro is a precision 3-axis accelerometer, a sensor that measures acceleration also known as G-Force. G-Force is what's keeping you in your seat and if it wasn't for that seat you would be accelerating to the ground at 1 G (32 feet per second per second).
Acceleration is measured in Gs and is one of the key things the G-TECH/Pro COMPETITION is measuring. You can see this when you position the unit horizontally, it will show 0.00G's on the X acceleration bar. If you position it vertically it will show 1.00G's.
Speed:
The G-Tech measures your speed and distance traveled by integrating forward (the forward direction is chosen automatically) acceleration over time. Basically, if you know how fast you are accelerating for a certain time period you'll know how much your speed changed after that time period. So if you start off from zero speed then you'll know what your speed is after every time period. These time periods are very small (a few thousandths of a second) and that's how G-Tech maintains its accuracy. However, if you don't start from zero speed your measurement won't be correct because you won't have a good reference point. Consequently, it's very important to start all of your measurements from an absolute standstill.
Distance:
Distance is measured in the same fashion, if you know how fast you are going for a certain time period you will know what is the distance traveled during that time period.
Horsepower:
The G-Tech measures horsepower though the formula: speed times acceleration times the weight of the vehicle. The more accurate the vehicle weight you enter, the better your measurement. The G-Tech measures delivered horsepower, sometimes also called Rear Wheel Horsepower. This horsepower includes the loss of power through the drive train which is usually 10-15%. Rear Wheel Horsepower is what most people are interested in because that is what they experience when driving. The use of Flywheel Horsepower measurement is often used in advertising, but not very realistic when it comes to accelerating your vehicle.
The horsepower that G-Tech measures also includes vehicle aerodynamic drag. This means that if you tape over your headlights and grill, remove rear view mirrors and windshield wipers to reduce your drag, you will measure a Horsepower increase even though you didn't make any changes to the engine. After adding an aftermarket spoiler you will likely find a decrease in measured horsepower, since you increased the drag losses on your vehicle.
RPM:
Engine RPMs are sensed directly from the cigarette lighter voltage. No installation required at all with this true plug and play feature. The unique RPM feature is used for anything from real-time torque measurements to shift lights.
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Okay, so, its not really all that hard, aside from voltage from cig lighter, but why do we need rpm anyway, i dont see rpm needed in the formula.
So, my thoughts, again, are:
You hit start on the program, it displays maybe the christmas tree (drag racers know what i'm talking about), but doesnt actually start registering until the accelerometer feels the lurch of the vehicle when you launch.
Okay, and to end it, you get on the brakes and it senses the g's going the other way. Okay, easy enough, BUT, how will it know when you go 1/4mile (or even 1/8 mile)? I dont know the gps in those phones is accurate enough for a tie-in, so the only thing i can think of is you actually mark it out.
And for it to derive apx horsepower, you set up the program before you hit the "Start" button (obviously have it save info). Weight is usually the biggest thing (in fact, i can't think of anything else to add).
If someone shows a little interest, I can post up the formulas. There are a few different ones, so if we take those few and average them out, it should give a decent estimation of HP.
