Temperature compensation

From Gluonpilot

Often marketeers try to promote their products by saying all their sensors are "temperature compensated". While this is important, it not so hard to accomplish this.

Let's do a simple experiment:

• Plot the temperature's and the accelerometer's value on a figure.
• At the beginning the temperature will rise (the processor generates some heat).
• After a while I will blow softly on the module (for a minute or so). This should make the temperature drop.

The code to do this can be found in the "temperature_compensation" example. Using the gluon library, it's only a few lines long! Copy paste the output to excel . The raw accelerometer's output is normalized because the default value is around 22000. This would make it hard to visually compare it with the temperature. This is the result:

The orange line is the temperature: you can clearly see it heating up, and cooling down when I start blowing on it. Also pay attention to the shape of those 2 lines: the temperature seems to be scaled down version of the accelerometer's output!

With some excel tricks, it's easy to scale the accelerometer's output to the temperature. Substracting those 2 values generates our temperature compensated output!