CHR-6d Inertial Measurement Unit (6DOF) - with


chr-6d_quarter.jpg* IMU weighs less than 1.5 grams* .8" x .7" footprint* Customizable FIR digital filter* TTL UART communication interface* 16-bit ADC resolution* +/- 400 deg/s gyro dynamic range* +/- 3 g accelerometer dynamic rangeSophisticated onboard filtering, simple user-interfaceThe CHR-6d Inertial Measurement Unit includes a customizeable Parks-McClellan windowed FIR filter to process sensor data. The filter is easily customized by sending commands over the TTL UART.Open-source firmware makes the CHR-6d fully customizableWhile the CHR-6d comes ready to use, it can also be reprogrammed for specialized applications. In addition to the UART, four extra GPIO pins are routed out for additional flexibility. At 64 Mhz, the onboard ARM Cortex™ processor is fast enough to handle a wide variety of sensing and control tasks.On their products page (, they also make mention of this :CHR-9d Inertial Measurement UnitComing soon - the CHR-9 line incorporates rate gyro, accelerometer, and magnetometer data to create a self-contained attitude estimation system.No news yet on pricing, but they said it should be available in Oct 2009.
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  • Robin -
    You are right, the group delay for the FIR filter is fairly long, especially considering that the internal sample rate of the IMU is only 350 Hz, and considering that the filters are linear-phase. I set it up so that you can change the number of taps in the filter from 8, 16, 32, or 64, depending on how sensitive the application is to group delay.
  • An IIR filter option would have been nice since the FIR group delay is quite long for higher orders. It is stable at least.

    However. Will definitely pick one up. Good work!
  • It's made by fellow DIYDrones member Caleb Chamberlain.
  • Developer
    Same idea as the unav but better in my opinion because you have acess to the code as well as its simply more open to acustom the flight dynamics (ie taking outside imputs to subtract centripetal) where as the unav will absolutely not work in an aircraft and leaves you with zero option.
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