Discontinuation Notice: This module has been replaced by the much more capable CHR-UM6-LT orientation sensor.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.
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Overview
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 |  |
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| CHR-6d IMU * | |
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| CHR-UM6-LT Orientation Sensor | |
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| CHR-UM6 Orientation Sensor | |
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* Discontinued.
Features
- 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
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- 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
