WITMOTION HWT901B-TTL 9-Axis Accelerometer and Inclinometer User Manual

1. Introduction

This user manual provides detailed instructions for the setup, operation, calibration, and maintenance of the WITMOTION HWT901B-TTL 9-Axis Accelerometer and Inclinometer. This device is designed for precise motion sensing applications, integrating a gyroscope, accelerometer, digital compass, air pressure sensor, and altitude measurement capabilities. It features RM3100 magnetometer compensation and Kalman filtering for enhanced accuracy and stability.

2. Safety Information

Please read and understand all safety precautions before operating the device. Failure to follow these instructions may result in damage to the product or personal injury.

• Power Supply: Ensure the device is powered within its specified voltage range (e.g., 5V for TTL version). Incorrect voltage can cause permanent damage.
• Connections: Verify all wiring connections are correct before applying power. Incorrect wiring can lead to short circuits or component failure.
• Environment: Avoid exposing the device to extreme temperatures, humidity, or corrosive environments unless specifically rated for such conditions.
• Handling: Handle the sensor with care to prevent physical shock or damage to internal components.
• Calibration: Perform calibration procedures in a stable environment, free from strong magnetic interference, to ensure accurate readings.

3. Package Contents

Upon opening the package, please verify that all items listed below are present and in good condition.

• 1 x HWT901B-TTL Sensor
• 1 x Connection Cable
• 1 x Instruction Card
• (Optional, depending on kit) USB-TTL Serial Converter
• (Optional, depending on kit) Type-C Adapter

4. Product Overview

The WITMOTION HWT901B-TTL is an industrial-grade 9-axis sensor module designed for high-precision attitude measurement. It integrates a 32-bit processor, MPU9250 (accelerometer, gyroscope), RM3100 magnetometer, and a BMP280 air pressure sensor. The device utilizes advanced R&D dynamic fusion algorithms and Kalman filtering to provide stable and accurate data output for pitch, roll, yaw, acceleration, angular velocity, magnetic field, air pressure, and altitude.

Key Features:

• 10-Axis Measurement: Pitch, Roll, Yaw (X, Y, Z axis), Accelerometer, Angular Velocity, Angle, Magnet Field, Air Pressure, Height.
• High Accuracy: Angle measurement accuracy up to 0.05 degrees (X, Y-axis) with low Z-axis drift.
• Advanced Filtering: Integrated Kalman Algorithm and RM3100 magnetometer compensation for stable and precise data.
• Robust Design: Equipped with a 32-bit processor and highly-integrated MEMS module for performance in challenging environments.
• Selectable Output Rate: Data output rate configurable from 0.2Hz to 200Hz.

5. Setup Instructions

5.1. PC Connection

1. Install Serial Driver: Download and install the appropriate serial driver (e.g., CH340) for your operating system.
2. Connect Hardware: Connect the HWT901B-TTL sensor to your PC using a USB-TTL serial converter. Ensure VCC, TX, RX, and GND pins are correctly matched (VCC-VCC, TX-RX, RX-TX, GND-GND).
3. Identify COM Port: Open Device Manager on your PC and locate the assigned COM port for the serial converter.
4. Launch Software: Open the WITMOTION PC software (Minimu.exe).
5. Select Port and Baud Rate: In the software, select the identified COM port and the correct baud rate (default is typically 9600). Data should appear automatically. If not, manually select the COM port and baud rate.

Video Guide: PC Connection and Basic Operation

This video demonstrates the process of connecting the HWT901B-TTL sensor to a PC, installing necessary drivers, and viewing data using the WITMOTION software.

5.2. Android Smartphone Connection

1. Install APP: Install the WITMOTION APK file on your Android smartphone. Grant necessary permissions, especially "Storage" and "Location".
2. Prepare Hardware: You will need the HWT901B-TTL sensor, a USB-TTL cable, and a Type-C OTG adapter (if your phone has a Type-C port, adapter may need to be purchased separately).
3. Connect Hardware: Connect the sensor to the USB-TTL cable, then connect the USB-TTL cable to your smartphone via the OTG adapter.
4. Open APP: Launch the WITMOTION APP.
5. Select Module Type: Choose "9-axis Series" from the module selection.
6. Select Baud Rate: Select the appropriate baud rate (default 9600). Connection should succeed, and data will be displayed.

Video Guide: Android Smartphone Connection

This video illustrates the steps to connect the HWT901B-TTL sensor to an Android smartphone and view real-time data through the WITMOTION application.

6. Operating Instructions

The WITMOTION software and Android app provide various interfaces for monitoring and configuring the HWT901B-TTL sensor.

6.1. Data Display

Once connected, the software/app will display real-time sensor data, including:

• Main Interface: Shows current Pitch, Roll, and Yaw angles.
• Acceleration Graph: Visualizes X, Y, Z axis acceleration over time.
• Angular Velocity Graph: Displays X, Y, Z axis angular velocity over time.
• Angle Graph: Plots Pitch, Roll, and Yaw angles over time.
• Magnetic Field Graph: Shows magnetic field strength along X, Y, Z axes.
• Data Review: Presents raw and processed data in tabular format.

6.2. 3D Demonstration

The PC software includes a 3D visualization tool that allows you to observe the sensor's orientation in real-time. You can select different 3D models (car, head, plane, cube) to represent the sensor's movement.

Before using the 3D demonstration, calibrate the direction of the 3D model using the arrow control keys to match the sensor's axial direction.

7. Calibration

Regular calibration ensures the highest accuracy of the HWT901B-TTL sensor. Perform calibration in a stable environment, away from strong magnetic fields.

7.1. Acceleration Calibration

1. Place the module face up on a horizontal plane.
2. In the software/app, navigate to the calibration section and select "Acceleration Calibration".
3. Click "Start Calibration". The system will automatically calculate the calibration value. Keep the module still for 2-3 seconds.
4. Click "Complete Calibration" or "End Calibration".
5. Click "Write Parameter" or "Save Config" to save the parameters to the sensor.
6. To confirm successful writing, read the parameters again. After calibration, the Z-axis acceleration should read approximately 1g.

7.2. Magnetic Field Calibration

Magnetic field calibration compensates for local magnetic interference.

1. In the software/app, navigate to the calibration section and select "Magnetic Field Calibration".
2. Click "Start Calibration".
3. Rotate the sensor 360 degrees around its X, Y, and Z axes respectively. Ensure the sensor covers a full sphere of orientations during rotation.
4. Click "End Calibration" or "Magnetic Field Calibration Finish".
5. Click "Write Parameter" or "Save Config" to save the parameters to the sensor.

8. Data Logging and Export

The WITMOTION software and app allow you to record and export sensor data for further analysis.

• Recording: In the software/app, navigate to the "Record" or "Data" tab and click the "Start" or "Record" button to begin logging data.
• Stopping: Click "Stop" to end the recording.
• Export: The recorded data can typically be extracted as a TXT file or other formats (e.g., CSV, BIN, PLAY) depending on the software version. For Android, recorded files are usually saved in the phone's root directory under a "Records" folder.

9. Maintenance

To ensure the longevity and optimal performance of your HWT901B-TTL sensor, follow these maintenance guidelines:

• Cleaning: Keep the sensor clean and free from dust and debris. Use a soft, dry cloth for cleaning. Avoid using harsh chemicals or abrasive materials.
• Storage: Store the sensor in a dry, cool environment when not in use. Protect it from extreme temperatures and humidity.
• Cable Integrity: Regularly inspect the connection cable for any signs of wear, cuts, or damage. Replace damaged cables immediately.
• Firmware Updates: Check the official WITMOTION website (wit-motion.com) for any available firmware updates to improve performance or add new features.

10. Troubleshooting

If you encounter issues with your HWT901B-TTL sensor, refer to the following common problems and solutions:

11. Specifications

Video Guide: Temperature Aging Test

This video demonstrates the temperature aging test process, ensuring stable accuracy across the sensor's operating temperature range.

Video Guide: High-Precision Turntable Calibration

This video shows the high-precision turntable calibration process performed before packaging, ensuring the sensor's accuracy.

12. Warranty and Support

WITMOTION provides comprehensive support for its products:

• Warranty: The HWT901B-TTL comes with a 12-month warranty.
• Customer Service: Lifetime friendly customer service is available from the WitMotion team.
• Documentation: For complete tutorials, software, and instructions, visit wit-motion.com and navigate to the support page or the WITMOTION Google Drive.
• Video Resources: Find instructional videos and project sharing on the official WITMOTION Youtube channel.
• Contact: For any assistance, contact support at support@wit-motion.com.