CHR-6d Inertial Measurement Unit

via Pololu
SKU PL-1263

Discontinuation Notice: This module has been replaced by the much more capable CHR-UM6-LT orientation sensor. For an alternative IMU, please consider the Pololu MinIMU-9.


The CH Robotics CHR-6d inertial measurement unit (IMU) uses a 32-bit STM32F103T8 ARM Cortex processor to take 16-bit ADC readings from an ADXL335 three-axis accelerometer, a LP510AL pitch/roll rate gyro, and a LY510ALH yaw rate gyro, providing a full six degree of freedom (6-DOF) measurement solution. The Cortex processor applies a customizable finite impulse response (FIR) digital filter to help reduce noise and makes the results available via a simple TTL-level (3.3V with 5V-tolerant pins) serial interface at baud rates up to 115,200 bps. A USB-to-serial adapter can be used to connect the IMU to a computer running the free IMUkit PC application, which can be used for data visualization and settings configuration.

Update: Units are now being shipped with firmware version 2.0, which adds an on-board Extended Kalman Filter (EKF) for automatic pitch and roll angle estimation.

Note that the board’s pins are spaced 2 mm apart, so the board will not work with standard 0.1" headers or breadboards.

Product Comparison

We carry several inertial measurement and orientation sensors. The table below compares their capabilities:

Product Name Sensors Estimation Other
Gyros (3x) Accels (3x) Mag (3x) Roll Pitch Yaw Quaternion Enclosure
Pololu MinIMU-9
CHR-6d IMU *
CHR-UM6-LT Orientation Sensor
CHR-UM6 Orientation Sensor

* Discontinued.

  • On-board EKF for pitch and roll angle estimation (firmware version 2.0+ only)
  • 3 gyro axes and 3 accelerometer axes
  • ±400°/s gyro range
  • ±3 g accelerometer range

  • Data output rate adjustable from 20 to 300 Hz
  • Weighs under 1.5 grams (0.05 oz)
  • Small size: 20 x 18 x 3 mm (0.8" x 0.7" x 0.1")
  • Configurable windowed Parks-McClellan FIR filter
  • TTL UART communication interface (3.3V with 5V-tolerant pins) can stream data or provide data on request
  • 16-bit angle outputs provide 0.01° resolution
  • Cortex firmware and PC application can be customized
Open Source PC Application and Firmware

The CHR-6d can be used in applications where a compact, 6-DOF IMU is needed, including:

  • UAV navigation
  • Robotics
  • Motion tracking
  • Platform stabilization
  • Image stabilization
  • Supplement to GPS navigation