[eugenebrooks]

The ADXRS150 gyro chip is "additional electronics" and a strict interpretation of the build rules is that it must be powered via the 12 volt power. The rule allowing the "old kit supplied gyro" to be hooked to the 5 volt power from the RC may or may not apply to the ADXRS150 listed as additonal electronics. The gyro data sheet also indicates that it is sensitive to noise on the power line, specifically warning that the power from a computer that might be subject to a lot of noise. You can satisfy the build rules, and any power line noise issue, by putting a filter and regulator on the board mouting the gyro. We use a Digikey DN4523-ND 820 microhenry inductor feeding a Digikey 4051PHCT-ND 220 microfarad capacitor, feeding a Digikey LM340-ND five volt regulator. The ground reference is the ground line on the computer, not the ground from the power bus.

As noted in a separate post, you use trapazoidal rule time integration. It costs virtually nothing extra but gives second order accuracy.

Depending upon the rate at which you are sampling the gyro, you may want to reduce the output bandwidth of the gyro by adding a capacitor according to the data sheet. Doing this will also drop the noise floor of the gyro. You are probably okay sampling at 100 hertz, as this is more than twice the 40 hertz bandwitdh of the gyro, but if you are sampling at the packet loop rate you should cut the gyro bandwith by at least a factor of two.

Finally, you want to consider using "fixed binary point" arithmetic to integrate the gyro, using precision of 1/4 or 1/8 instead of 1. By doing this you can calculate the "average" of the gyro with no turn using better precision than 1. The "zero signal" values vary due to noise and drift, and you want to compute the average to subtract accurately.

Fixed "binary point" arithmetic is easily implemented with normal integer operations (possibly using the "long int" type to get the needed headroom) using shifts appropriately to correctly normalize a multiply, or to put a value read from the gyro into the correct normalized form. Minimizing drift would be relatively important if you are going to use the gyro to "go straight."

We have not seen a significant difference in calibration of the left and right turn directions of the ADXRS150 gyro, but this was for a relatively quick turn.

Have fun!