Camber smartphone electronic measurement accuracy & precision

I'm sure it depends on how accurately you park the vehicle on the phone. :-)

Jon esy-- Marvin L Jones | Marvin | W3DHJ.net | linux 38.238N 104.547W | @ jonz.net | Jonesy | FreeBSD * Killfiling google & XXXXbanter.com: jonz.net/ng.htm

The three measurements that we need to accuracy & precision of about a tenth of a degree are caster, camber, and toe.

Since toe can be more easily measured linearly, only tenths of a degree accuracy & precision would be required for measuring Caster & for calculating Camber.

For toe, we can obtain linear equivalents simply by converting a factory

a. P235/45R17 = (235)(2)(0.45)(1/25.4) + 17 or about 25.3"

c. Toe from tread centerline to vehicle centerline is half that

g. 0.0124" is roughly about 3/256ths" (or about 0.3mm)

The rears, calculated similarly, would be ~0.33" for total toe in.

We could also use the sine instead of the tangent if we consider the radius of the tire to be the hypotenuse (the linear measurements are likely to be taken at right angles to the centerline of the car, or an imaginary line through the steering axis parallel to same) not at right angles to the tire centerline; but at these tiny angles sine and tangent are basically the same anyway so that makes no significant difference where the major linear measurement error is likely in the gravitational bowing of the typical tape measure. Hence the toe measurement accuracy & repeatability is due more to the fact that the tire isn't very large, and the factory-specified angle is very small, causing even a miniscule difference in distance with the tape measure to translate to a fairly large portion of the angle.

Given that both toe and caster can be derived from other measurements, the only question at hand is for Camber degrees to be measured by a smartphone.

For Camber, tenths of a degree in repeatability & accuracy would be nice. Does anyone here know if a typical smartphone can achieve that feat yet?

If not... When do you think phones will be able to achieve that accuracy & precision?

Nice try, but most of us have enough sense to have this done by someone with the correct equipment.

The MEMS accelerometer used in many smart phones is capable of 0.06 degrees of resolution (not accuracy). The device will need to be calibrated against a 0 degree horizontal flat surface (easily done by vertically rotating the MEMS sensor and adjusting for zero change) to obtain such levels of camber accuracy. The limiting factor is the sensor noise level.

ADXL213AE datasheet

sensing applications using narrow bandwidths (If not.

When someone finds or creates a market for such a device.

You can try it yourself to see what can be achieved. There are many electronic bubble level apps for Android and iPhone: Most seem to display in 1 degree resolution, but there are a few that will display 0.1 degree resolution: I tried to use various Android apps for aligning satellite dishes, where +/-0.5 degrees or better accuracy is the norm: but found that a digital angle level was more useful:

These look interesting:

Why does this idiot troll have any traction in this group whatsoever?

Any idiot that would use a cell-phone or any similar device to check critic al measurements in a vehicle deserves exactly what it gets. The sad part, o f course, is when it gets what it deserves, it is more than likely to take one-or-more innocents with it. Of course, one is entirely and fully entitle d to compete for a Darwin Award, but not to threaten others in the process.

Peter Wieck Melrose Park, PA

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