UM6-LT Orientation Sensor

The UM6-LT ultra-miniature orientation sensor from CH Robotics is uses rate gyros, accelerometers, magnetic sensors, and an on-board 32-bit ARM Cortex processor to compute sensor orientation 1000 times per second. Sensor orientation is reported using either quaternions or Euler angles over a TTL serial interface at user-customizable rates.

Not currently available

Our Code: SEN-10037

Supplier Link: [Pololu MPN:1256]

Discontinued. Replaced by SEN-10068: UM7 Orientation Sensor

Overview

The UM6-LT ultra-miniature orientation sensor—also known as an Attitude and Heading Reference System, or AHRS—from CH Robotics is an OEM version of their UM6 orientation sensor. Like the UM6, it uses rate gyros, accelerometers, magnetic sensors, and an on-board 32-bit ARM Cortex processor to estimate the absolute sensor orientation 1000 times per second. Sensor orientation is reported using either quaternions or Euler angles over a TTL serial interface at user-customizable rates. A USB-to-serial adapter can be used to connect the IMU to a computer running the free CH Robotics Serial Interface PC application, which allows for easy data visualization, board calibration, and UM6-LT settings configuration.

The UM6-LT is functionally identical to the UM6 (it uses the same firmware and works with the same PC software). The only difference is that the UM6-LT lacks the UM6’s enclosure and 4-pin connector. Please see the UM6/UM6-LT datasheet (475k pdf) for board specifications and usage information.

The UM6-LT is a pin-compatible replacement for the CHR-6dm AHRS sensor, which has been discontinued, so it can be physically swapped directly into systems that use the CHR-6dm. However, the UM6-LT uses the UM6 communication protocol, not the CHR-6dm protocol, so such a swap will require software modification.

Specifications

Dimensions

Size:	1.0" x 0.96" x 0.1"
Weight:	2.5 g

General specifications

Interface:	TTL serial
Baud:	115200 bps
Minimum operating voltage:	3.5 V
Maximum operating voltage:	5 V
Axes:	pitch (x), roll (y), and yaw (z)
Measurement range:	±2000°/s (gyro) ±2 g (accelerometer)
Supply current:	52 mA

Resources

File downloads

Datasheet for the CHR-UM6 orientation sensor (475k pdf)
Getting Started with the UM6 Orientation Sensor (675k pdf): This application note provides instructions for communicating with, configuring, and calibrating the UM6 and UM6-LT orientation sensors from CH Robotics.
Understanding Euler Angles (255k pdf): The UM6 and UM6-LT orientation sensors use Euler angle representations by default , and this application note from CH Robotics helps explain what Euler angles are.
Understanding Quaternions (57k pdf): The UM6 and UM6-LT orientation sensors can represent orientation with quaternions, which avoid certain problems that can occur when using Euler angles. This application note from CH Robotics helps explain what quaternions are and how to use them.
Estimating Velocity and Position Using Accelerometers (43k pdf): This application note describes how to use the UM6 or the UM6-LT to estimate velocity and position (dead-reckoning using accelerometers). It also explains why this estimate will not be accurate enough for most applications.
Sensors for Orientation Estimation (127k pdf): The UM6 and UM6-LT orientation sensors each use a three-axis accelerometer, gyro, and magnetometer to estimate orientation. This application note explains in more detail the purpose of each sensor and the math involved in combining them.
Reprogramming the Firmware on the UM6 and the UM6-LT (243k pdf): The UM6 and UM6-LT orientation sensors are designed to be easily reprogrammed when a firmware upgrade is needed. This appplication note provides a detailed description of how to reprogram both devices.