NAVX vs. Spartan board

[Andrew_L]

Originally Posted by slibert

the Spartan requires mounting perpendicular to the robot chassis (parallel to the Z-axis plane)

[Citation needed]

[slibert]

Originally Posted by Andrew_L

[Citation needed]

Per the ADXRS453 datasheet, the Gyro on the gyro-enabled version of the Spartan board is single-axis, and is the SOIC_CAV package designed for yaw rate sensing. I haven't come across any Spartan board mounting instructions, but if we thus assume the purpose of the ADXRS453 is to be a yaw rate sensor, then any mounting configuration in which the sensor is not parallel to the FRC field surface will result in integrated yaw angles which include an error proportional to the offset angle from parallel. For instance, if the board is mounted vertically, the sensor would be measuring a "tip" or "tilt" angular rate rather than yaw. This is as compared to a triaxial gyro which can measure yaw rate even when mounted vertically.

If you think this is incorrect, please let me know.

[AustinSchuh]

Originally Posted by slibert

Per the ADXRS453 datasheet, the Gyro on the gyro-enabled version of the Spartan board is single-axis, and is the SOIC_CAV package designed for yaw rate sensing. I haven't come across any Spartan board mounting instructions, but if we thus assume the purpose of the ADXRS453 is to be a yaw rate sensor, then any mounting configuration in which the sensor is not parallel to the FRC field surface will result in integrated yaw angles which include an error proportional to the offset angle from parallel. For instance, if the board is mounted vertically, the sensor would be measuring a "tip" or "tilt" angular rate rather than yaw. This is as compared to a triaxial gyro which can measure yaw rate even when mounted vertically.

If you think this is incorrect, please let me know.

That is correct. The roboRIO needs to be horizontal.

We developed the Spartan Board mostly to solve brownouts and latching connectors. If it hadn't been for the brownout problems with the roboRIO, we would have likely developed the board only for 971 and not bothered to sell it. The regulators brown out right about when the roboRIO CPU browns out.

We've been using the ADXRS453 for a number of years, and have been impressed with it. Once you are making a board with a bunch of active circuitry, adding a gyro is easy. I might have picked a different gyro if I were to start over today.

One of the main drivers for selling the board was because there was enough interest from our friends in the board that we couldn't continue to fabricate enough of them each season. By selling it, we were also able to get it approved by FIRST, and add PWM pass-throughs. Selling the board has honestly been a lot of work... RC and WCP have been a huge part of figuring out how to build the boards in quantity and to sell them.

[Andrew_L]

Originally Posted by slibert

Per the ADXRS453 datasheet, the Gyro on the gyro-enabled version of the Spartan board is single-axis, and is the SOIC_CAV package designed for yaw rate sensing. I haven't come across any Spartan board mounting instructions, but if we thus assume the purpose of the ADXRS453 is to be a yaw rate sensor, then any mounting configuration in which the sensor is not parallel to the FRC field surface will result in integrated yaw angles which include an error proportional to the offset angle from parallel. For instance, if the board is mounted vertically, the sensor would be measuring a "tip" or "tilt" angular rate rather than yaw. This is as compared to a triaxial gyro which can measure yaw rate even when mounted vertically.

If you think this is incorrect, please let me know.

My apologies, I was assuming you meant to say either of the Spartan Boards could not physically be mounted in other planes. I didn't want teams getting the wrong idea that they couldn't mount a Spartan Board without gyro any direction other than parallel with the floor.