jremington

Member Since: March 31, 2006

Country: United States

  • The code has never worked properly. See most recent comments, and the fix.

  • The Sparkfun example code MPU9250BasicAHRS_I2C does not work out of the box, because the I2C address is incorrect. Fix that, and also enable the magnetometer calibration.

    See also the major bug that produces nonsensical yaw, pitch and roll angles, reported in a separate comment below.

  • The Sparkfun code MPU9250BasicAHRS_I2C has a serious bug that makes the yaw, pitch and roll angles nonsense. The bug is also in Kris Winer's original BasicAHRS code for Arduino/MPU-9250. The magnetometer coordinate system as defined is left handed and has NEVER worked properly. See issue #368 on Kris Winer's Github page.

    A simple fix to the code is to invert the sign of mz, AS SHOWN IN THE FOLLOWING, CORRECTED LINE:

    MahonyQuaternionUpdate(myIMU.ax, myIMU.ay, myIMU.az, myIMU.gx * DEG_TO_RAD, myIMU.gy * DEG_TO_RAD, myIMU.gz * DEG_TO_RAD, myIMU.my, myIMU.mx, -myIMU.mz, myIMU.deltat);

    Of course, if the magnetometer is not properly calibrated, the orientation angles will also be nonsense, so activate the built in calibration procedure, and make sure that all possible magnetometer orientations are sampled reasonably well in the 15 seconds you are given.

    With the above fix, and the magnetometer properly calibrated, yaw = 0 corresponds to the acelerometer/gyro X axis pointing toward magnetic North, Yaw increases as the X-axis sweeps toward West (unlike a magnetic compass). See the comments in the code to interpret the meaning and signs of the other angles.

  • The Fritzing diagram showing the "setup", a Pro Mini connected to the sensor, is an abomination and an excellent example of why Fritzing should not be used.

    The diagram does not label the I2C connections on the Pro Mini, and fails to make it clear to beginners how to connect SDA and SCL to any other MCU board.

    I am really sorry to see that Sparkfun has abandoned clear communications in favor of idiot diagrams.

  • "The AS7263 should not be confused with highly complex mass spectrometers". True, since mass spectrometers measure PARTICLE MASS, not light.

  • In addition to the comment about "overclocking" below, the RXI input on OpenLog (advertised as 3.3-6V) is 3.3 V ONLY. The schematic shows no RXI series resistor or level shifting, so it is presumed unsafe to connect this line to 5V TX pins. I've complained about this irresponsible advertising to SparkFun, but the engineers can't seem to get the web pages corrected.

    OpenLog does work very well. My approach, when connecting OpenLog to a 5V TX line, is to put a 4.7K resistor in the line to protect the input clamp diode and the uSD card.

  • Does anyone know if President Obama will be entering a drone?

  • This product has an unresolved issue with crashing and watchdog resets and is thus unreliable even in normal applications. See the RF/Wireless forum for more information.

    http://forum.sparkfun.com/viewtopic.php?f=13&t=28926

  • Your calculation does not include the cost of storage batteries or an inverter, which is often about equal to the cost of the panels.
    Xcel Energy says "A common size ... for systems in Colorado is 2-3 kilowatts, and total payments to customers for this size would be in the $9,000 to $13,500 range ... typical photovoltaic systems are priced at $8,000 to $10,000 per kilowatt."
    However, a 2-3 kW system probably won't cover your electrical needs, unless you are very frugal.
    Jim

No public wish lists :(