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3-Space Watertight USB/RS232



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Product Overview

The YEI 3-Space Sensor™ Watertight USB/RS232 is a miniature, high-precision, high-reliability, Attitude and Heading Reference System (AHRS) / Inertial Measurement Unit (IMU) offering USB 2.0 and RS232 communication interfaces in a single low-cost end-use-ready IP67 sealed case. The Attitude and Heading Reference System (AHRS) uses triaxial gyroscope, accelerometer, and compass sensors in conjunction with advanced processing and on-board quaternion-based orientation filtering algorithms to determine orientation relative to an absolute reference in real-time.

Orientation can be returned in absolute terms or relative to a designated reference orientation. The gradient descent calibration process and high update rates increase accuracy and greatly reduce and compensate for sensor error. The YEI 3-Space Sensor system also utilizes a dynamic sensor confidence algorithm that ensures optimal accuracy and precision across a wide range of operating conditions.

The YEI 3-Space Sensor Watertight USB/RS232 unit's features are accessible via a well-documented open communication protocol that allows access to all available sensor data and configuration parameters using either USB 2.0 or RS232. Versatile commands allow access to raw sensor data, normalized sensor data, and filtered absolute and relative orientation outputs in multiple formats including: quaternion, Euler angles (pitch/roll/yaw), rotation matrix, axis angle, two vector(forward/up).

YEI 3-Space Sensor USB/RS232

Areas of Application

  • Robotics
  • Motion capture
  • Positioning and stabilization
  • Personnel/pedestrian navigation and tracking
  • Unmanned air/land/water vehicle navigation
  • Education and performing arts
  • Healthcare monitoring
  • Gaming and motion control
  • Accessibility interfaces
  • Virtual reality and immersive simulation

Hardware Overview

YEI 3-Space Sensor

Key Features

The YEI 3-Space Sensor Watertight USB / RS232 has many features that allow it to be a flexible all-in-one solution for your orientation sensing needs. Below are some of the key features:

  • Small self-contained high-performance AHRS at 35mm x 67.6mm x 20mm and 21 grams
  • Fast sensor update and filter rate allow use in real-time applications, including stabilization, virtual reality, real-time immersive simulation, and robotics
  • Highly customizable orientation sensing with options such as tunable filtering, oversampling, and orientation error correction
  • Advanced integrated Kalman filtering allows sensor to automatically reduce the effects of sensor noise and sensor error
  • Robust open protocol allows commands to be sent in human readable form, or more quickly in machine readable form
  • Orientation output format available in absolute or relative terms in multiple formats (quaternion, rotation matrix, axis angle, two-vector)
  • Absolute or custom reference axes
  • Access to raw sensor data
  • Flexible communication options: USB 2.0 or RS232 asynchronous serial
  • USB communication via virtual COM port
  • USB joystick/mouse emulation modes ease integration with existing applications
  • Upgradeable firmware
  • RGB status LED, two programmable input buttons
  • IP67 rated connector provides power, USB, and RS232 connections
  • Available in screw-down water-tight silicone-sealed IP67 rated enclosure



Part number TSS-USBWT-S (Watertight Screw-down Sensor Unit)
Dimensions 35mm x 67.6mm x 20mm (1.38 x 2.66 x 0.79 in.)
Weight 21 grams (0.74 oz)
Supply voltage +5v USB, +3.3v~+6.0v for RS232
Communication interfaces USB 2.0, RS232 Asynchronous Serial
Serial baud rates 1,200~921,600 selectable, default: 115,200
Filter update rate up to 250Hz with Kalman AHRS(higher with oversampling)
up to 850Hz with QCOMP AHRS(higher with oversampling)
up to 1350Hz in IMU mode
Orientation output absolute & relative quaternion, Euler angles, axis angle, rotation matrix, two vector
Other output raw sensor data, normalized sensor data, calibrated sensor data, temperature
Shock survivability 5000g
Temperature range -40C ~ 85C (-40F ~ 185F)


Orientation range 360º about all axes
Orientation accuracy ±1º for dynamic conditions & all orientations
Orientation resolution <0.08º
Orientation repeatability 0.085º for all orientations
Accelerometer scale ±2g / ±4g / ±8g selectable for standard models
±6g / ±12g / ±24g selectable for HH models(coming soon)
±100g / ±200g / ±400g selectable for H3 models(coming soon)
Accelerometer resolution 14 bit, 12 bit(HH), 12 bit(H3)
Accelerometer noise density 99µg/√Hz, 650µg/√Hz(HH), 15mg/√Hz(H3)
Accelerometer sensitivity 0.00024g/digit-0.00096g/digit
Accelerometer temperature sensitivity ±0.008%/°C, ±0.01%/°C(HH, H3)
Gyro scale ±250/±500/±1000/±2000 º/sec selectable
Gyro resolution 16 bit
Gyro noise density 0.009º/sec/√Hz
Gyro bias stability @ 25°C 2.5º/hr average for all axes
Gyro sensitivity 0.00833º/sec/digit for ±250º/sec
0.06667º/sec/digit for ±2000º/sec
Gyro non-linearity 0.2% full-scale
Gyro temperature sensitivity ±0.03%/°C
Compass scale ±0.88 Ga to ±8.1 Ga selectable  (±1.3 Ga default) 
Compass resolution 12 bit
Compass sensitivity 0.73 mGa/digit
Compass non-linearity 0.1% full-scale


YEI 3-Space Sensor Watertight USB/RS232

Downloads and Documentation


Technical Brief: 3-Space Sensor Watertight USB/RS232, 3.0r1, updated 4 Nov 2014, Includes product data and specifications

3-Space Sensor Quick Start Manual USB3.0r1, updated 4 Nov 2014

3-Space Sensor User's Manual USB3.0r1, updated 4 Nov 2014

3-Space Sensor Watertight USB/RS232 Cable Pinout Details


3-Space Firmware Update - Watertight USB/RS232, 3.0r7, updated 17 Mar 2015

Change Log

Informational Resources


http://en.wikipedia.org/wiki/USB#USB_2.0 - Wikipedia entry describing USB 2.0 communication

http://en.wikipedia.org/wiki/Rs232 - Wikipedia entry describing RS232 serial communication

http://en.wikipedia.org/wiki/Asynchronous_serial_communication - Wikipedia entry describing asynchronous serial communication