1. Product Overview
The WitMotion HWT905 is a high-accuracy 9-axis Attitude and Heading Reference System (AHRS) sensor designed for precise motion and attitude measurement. It integrates an accelerometer, gyroscope, and magnetometer, enhanced with military-grade temperature and magnetometer compensation for reliable performance in various environments. The sensor offers multiple interface options (TTL, RS232, RS485) and features an IP67 waterproof design, making it suitable for demanding applications.
2. Package Contents
Upon opening the package, ensure all items are present and in good condition:
- 1 x HWT905 Sensor
- 1 x Instruction Card
- 1 x Connection Cable
3. Setup
3.1 Power Supply Requirements
- TTL Version: 3.3V - 5V DC
- RS232/RS485 Versions: 9V - 36V DC
3.2 Connection Diagrams
Connect the HWT905 sensor to your microcontroller (MCU) or computer using the appropriate wiring based on your sensor version:
3.2.1 TTL Level Connection
3.2.2 RS232 Level Connection
3.2.3 RS485 Level Connection
3.3 Software and App Installation
To utilize the sensor, download the necessary software and applications from the official WitMotion service website: https://wiki.wit-motion.com/english/doku.php?id=inclinometer. Select the 'HWT905' product type to find:
- PC Software (for Windows)
- Android APP (for TTL version only)
- Sample Code
- AD Package
Note: The Android APP supports connection only with the TTL version of HWT905. RS232 and RS485 versions are not supported by the Android APP. A Type-C adapter may be required for Android smartphone connections (not included).
4. Operating Instructions
4.1 Using PC Software
- Connect the HWT905 sensor to your computer via the appropriate interface (e.g., USB-to-serial adapter for TTL/RS232/RS485).
- Launch the WitMotion PC software.
- Select the correct COM port and baud rate in the software settings.
- The software will display real-time data for acceleration, angular velocity, angle, and magnetic field.
- Utilize the 3D demonstration feature to visualize the sensor's attitude in real-time.
- The software allows for data recording and review of recorded files.
4.2 Using Android APP (TTL Version Only)
- Connect the HWT905 TTL version sensor to your Android smartphone using a compatible adapter (e.g., USB-to-TTL adapter and Type-C adapter if needed).
- Open the WitMotion Android APP.
- Select the appropriate WT901 model and baud rate within the app.
- The app will display real-time acceleration, gyroscope, and angle data.
- Access configuration settings within the app for various adjustments.
4.3 Calibration
For optimal accuracy, especially for magnetic field measurements, calibration is recommended before usage. The PC software and Android APP provide options for both acceleration and magnetic field calibration. Follow the on-screen instructions within the software/app to perform these calibrations, typically involving rotating the sensor around its 3 axes.
5. Maintenance
The HWT905 sensor is designed for durability and performance:
- Waterproof Design: With an IP67 rating, the sensor is protected against dust and water immersion, ensuring accurate attitude data even in wet and cold conditions.
- Temperature Compensation: Built-in accelerometer SCA3300 chip and RM3100 magnetic field compensation ensure precise motion attitude data even in harsh environments.
- Environmental Considerations: To maintain accuracy, keep the sensor away from strong magnetic field interference.
6. Specifications
Key performance parameters of the HWT905 sensor:
| Number | Parameter | Description |
|---|---|---|
| 1 | Name | 9 Axis High Precision Attitude Sensor |
| 2 | Brand | WitMotion |
| 3 | Model | HWT905 |
| 4 | Weight | 100g |
| 5 | Volume | 55mm X 36.8mm X 24mm |
| 6 | Measuring | Acceleration: X Y Z Gyro: X Y Z Angle: X Y Z Magnetic field: X Y Z |
| 7 | Range | Acceleration: ±3g, ±8g (can be set by PC software) Gyro: ±2000°/s Angle: X/Z-axis: ±180°, Y-axis: ±90° |
| 8 | Stability | Acceleration: 0.01g, Gyro: 0.05°/s |
| 9 | Measurement Accuracy | X/Y axis: 0.05°, Z axis: 1° (No magnetic interference and after calibration) |
| 10 | Angle Stability | X/Y dynamic: 0.1°, static: 0.05° |
| 11 | Data Speed | 0.1Hz ~ 200Hz (10Hz Default) |
| 12 | Data Output | Time, Acceleration, Angular velocity, Angle, Magnetic field, Quaternion (Digital Output) |
| 13 | UART Interface | TTL/RS232/RS485 Baud rate support: 2400, 4800, 9600 (default), 19200, 38400, 57600, 115200, 230400, 460800, 921600 |
| 14 | Voltage Input | 3.3-5V (TTL version), 9-36V (RS232/RS485 version) |
| 15 | Consumption Current | <40mA |
| 16 | Built-in Chip | RM3100 module + SCA3300 Accelerometer + Gyroscope |
| 17 | Advantage | Temperature and Magnetometer Compensation |
| 18 | Working Temperature | -40 to +85 degree Celsius |
| 19 | Cable Length | 1m |
| 20 | Certification | CE |
Note: The angle of the Z-axis is solved by the magnetic field and will not drift. Keep away from magnetic field interference and calibrate before use.
7. Troubleshooting
7.1 Common Issues
- No Data Output: Check all physical connections, ensure the correct power supply voltage is applied for your sensor version, and verify the COM port and baud rate settings in your software/app.
- Inaccurate Readings: Perform magnetic field and acceleration calibration as described in Section 4.3. Ensure the sensor is not near strong magnetic interference sources.
- Android App Connection Issues: Confirm you are using the TTL version of the HWT905 sensor. Ensure any necessary adapters (e.g., Type-C) are correctly connected and functioning.
7.2 User Tips
- Data Logging: The HWT905 sensor does not have internal memory for data logging. Data must be continuously streamed and recorded by a connected device (PC or Android smartphone) running the WitMotion software/app. If internal memory for standalone data logging is a requirement, this specific model may not be suitable.
- Calibration is Key: Always perform magnetic field calibration in the environment where the sensor will be used to achieve the most accurate heading data.
- Software Resources: The official WitMotion service website (https://wiki.wit-motion.com/english/doku.php?id=inclinometer) is your primary resource for the latest software, drivers, sample code, and detailed documentation.
8. Warranty and Support
WitMotion provides lifetime technical support for the HWT905 sensor. For any technical inquiries, custom design requirements, or assistance, please contact WitMotion directly:
- Official Service Website: https://wiki.wit-motion.com/english/doku.php?id=inclinometer
- Email: javin@wit-motion.com
- Skype & WhatsApp & WeChat: (+86) 13005457470
