WITMOTION WT61C Inclinometer Sensor
User Manual
Tutorial Link
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If you encounter technical problems or need information not found in this manual, please contact the WITMOTION support team. Our engineering team is dedicated to providing the necessary support to ensure successful operation of our AHRS sensors.
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Application
- AGV Truck
- Platform Stability
- Auto Safety System
- 3D Virtual Reality
- Industrial Control
- Robot
- Car Navigation
- UAV
- Truck-mounted Satellite Antenna Equipment
1 Introduction
The WT61C is a multi-sensor device that detects acceleration, angular velocity, and angle. Its compact design makes it ideal for industrial retrofit applications such as condition monitoring and predictive maintenance. By interpreting sensor data through smart algorithms, the device can be configured to support a wide range of use cases.
The WT61C is scientifically known as an AHRS IMU sensor. It measures 3-axis angle, angular velocity, and acceleration, excelling in accurately calculating three-axis angles.
As an ISO standard accelerometer, the WT61C is suited for applications requiring high measurement accuracy. It offers several advantages over competing sensors:
- Heated for best data availability: Features a new WITMOTION patented zero-bias automatic detection calibration algorithm that outperforms traditional accelerometer sensors.
- High precision: Measures Roll, Pitch, Yaw (X, Y, Z axes) Acceleration, Angular Velocity, and Angle.
- Low cost of ownership: Includes remote diagnostics and lifetime technical support from the WITMOTION service team.
- Developed tutorial resources: Provides a manual, datasheet, demo video, free software for Windows, an Android app, and sample code for MCU integration (including 51 serial, STM32, Arduino, Matlab, Raspberry Pi) and communication protocols.
- WITMOTION sensors are recognized by thousands of engineers as a recommended solution for attitude measurement.
1.1 Warning Statement
- Applying more than 5 Volts across the sensor wiring of the main power supply can cause permanent damage to the sensor.
- Connecting VCC directly to GND will burn the circuit board.
- For proper instrument grounding, use WITMOTION with its original factory-made cable or accessories.
- For secondary development projects or integration, use WITMOTION with its compiled sample code.
2 Use Instructions with PC
2.1 PC Connection
The PC software is compatible only with the Windows operating system.
2.1.1 Serial Connection
Step 1: Connect the sensor using a serial converter.
PIN Connection:
- VCC - 5V
- TX - RX
- RX - TX
- GND - GND
(When connecting with a computer, VCC-5V is recommended.)
A table shows pin definitions: RED (VCC 5V), YELLOW (TX), GREEN (RX), BLACK (GND). A schematic illustrates the connection between a USB-to-TTL converter and the sensor module, with VCC, TX, RX, and GND lines clearly indicated.
2.1.2 Recommended Tools and Setup
Images display three types of serial converters: a 3-in-1 converter, a 6-in-1 converter, and a TTL serial cable.
Step 2: Unzip the software and install the driver (CH340 or CP2102, depending on the accessory used).
- Link to tutorial of 3-in-1 serial converter/ TTL serial cable (CH340 driver)
- Link to tutorial of 6-in-1 serial converter (CP2102 driver)
Step 3: Connect the converter to the computer and confirm the "COM port" in Device Manager.
A screenshot of the Windows Device Manager shows a list of devices, with "Silicon Labs CP210x USB to UART Bridge (COM15)" highlighted under "Ports (COM & LPT)".
Step 4: Open the software (Minimu.exe). Data will appear after auto-search finishes.
Notice: If the auto-search is unsuccessful, please operate manually. Choose the correct COM port and set the baud rate to 115200; data will then be displayed on the software.
2.2 Software Introduction
2.2.1 Main Menu
A screenshot of the WitMotion software's main interface displays angle readings for X, Y, and Z axes (-16.83°, 17.45°, -1.56° respectively). It also shows navigation menus (File, Tools, Record, 3D, Config, Help, Auto-search) and a compass rose visualization.
| Button | Function |
|---|---|
| File | Launch recorded HEX file (Bin format) |
| Tools | Hide or display tools box on left side |
| Record | Record function |
| 3D | 3D Unity DEMO |
| Config | Configuration setting |
| Help | Switch to English or Chinese |
| Bluetooth Set | Option for binding device or unbind |
| Firmware update | Option for firmware update |
| About Minimu | Info about Minimu.exe |
| Factory test | For manufacturer internal test only |
| Auto-search | Auto searching the sensor |
| Port | Com port selection |
Additional configuration options shown in the software interface:
| Baud | Baud rate selection |
| Type | Fixed setting as JY61 for WT61C |
| Open | Open com port |
| Close | Close com port |
| Acc Calibrate | Acceleration calibration |
2.2.2 Menu of Configuration
A screenshot of the "JY61-Config" window displays options for Reset Z-axis Angle, Acceleration Calibration, and Sleep. It also includes fields for Baudrate, Mode, Direction, Static Threshold, and Bandwidth.
| Button | Function |
|---|---|
| Zero Z Angle | Reset Z-axis angle to 0 degree |
| Acceleration Calibration | Ability to proceed accelerometer calibration |
| Sleep | Sleep function, not available for Bluetooth sensor series |
| Baudrate | 115200 (100Hz) (Fixed)/ 9600(20Hz) |
| Mode | Serial / IIC (only for modules) |
| Direction | Vertical or horizontal installation |
| Static threshold | Static threshold for angular velocity |
| Bandwidth | Option for bandwidth range |
2.2.3 Menu of Data
| Button | Function |
|---|---|
| Time | Real time |
| Acceleration | Data for Acceleration |
| Angular Velocity | Data for Angular Velocity |
| Angle | Data for Angle |
A screenshot of the WitMotion software's "Data" tab shows real-time readings for System time, Chip data, and relative time. It displays Acceleration (X, Y, Z), Angular Velocity (X, Y, Z), and Angle (X, Y, Z) values. Charts visualize acceleration and angular velocity, and a compass rose is displayed.
2.3 Calibration
Calibration and configuration on the PC software should be performed while the module is in the online state, indicated in the lower right corner of the software configuration bar. An "offline" status means the module is not controlled by the PC software. The module requires calibration before its first use. Customers need to calibrate the accelerometer and magnetometer; the gyroscope calibrates automatically.
2.3.1 Accelerometer Calibration
Purpose: To remove the zero bias of the accelerometer. Before calibration, bias errors may be present; after calibration, measurements become accurate.
Methods:
- First, keep the module horizontally stationary.
- Click "Acceleration Calibration" in the "Config" section of the software.
A screenshot of the "JY61-Config" window shows the "Acceleration Calibration" button highlighted, ready to be clicked after the module is placed horizontally.
Results: After approximately 1-2 seconds, the three axial acceleration values should be around 0, 0, and 1. The X and Y axis angles should be approximately 0°. After calibration, the x-y axis angle accuracy improves.
Note: When the module is placed horizontally, there is approximately 1 G of gravitational acceleration on the Z-axis.
A screenshot of the WitMotion software's "Data" tab displays readings after accelerometer calibration. The Z-axis acceleration is approximately 1.0000 g, while X and Y axis angles are close to 0°.
2.3.2 Reset Z-axis Angle
This function sets the initial Z-axis angle to 0 degrees. If the Z-axis drifts significantly during use, it can be recalibrated. Upon powering on, the Z-axis will automatically return to 0.
Step 1: Keep the module static.
Step 2: Click the "Config" button to open the configuration bar.
Step 3: Click the "Reset Z-axis Angle" option.
A screenshot of the "JY61-Config" window shows the "Reset Z-axis Angle" button highlighted, ready to be clicked after the module is placed statically.
Result: The angle of the Z-axis will return to 0 degrees in the module's data display.
A screenshot of the WitMotion software's "Angle" tab shows the Z-axis angle displayed as 0.00° after the reset operation.
2.4 Configuration
2.4.1 Set Baud Rate
The WT61C module supports multiple baud rates, with the default set to 115200. To change the baud rate, select the desired rate in the configuration bar, ensuring correct connection between the software and the module.
- Baud rate 115200 corresponds to a return rate of 100Hz.
- Baud rate 9600 corresponds to a return rate of 20Hz.
Note: After changing the baud rate, the module will no longer output data at the original rate. Data will only be output when the newly changed baud rate is selected on the PC software.
A screenshot of the "JY61-Config" window shows the Baudrate dropdown menu with "9600 (20Hz)" selected.
2.4.2 Data Recording
The sensor module does not have internal memory; data must be recorded and saved on the computer.
Method: Click "Record" and then "Begin" to save data as a TXT file. The saved file is located in the "Data" directory of the upper computer program. The beginning of the file contains values corresponding to the data.
A screenshot of the WitMotion software's "Record" tab displays fields for Time, Acceleration, Angular Velocity, and Angle, along with "Begin" and "Stop" buttons.
It is highly recommended to paste the recorded data into an Excel file for better organization and analysis.
A table shows sample recorded data with columns for StartTime, Time(s), ax(g), ay(g), az(g), wx(deg/s), wy(deg/s), wz(deg/s), AngleX(deg), AngleY(deg), AngleZ(deg), and T(°). This format is suitable for spreadsheet import.
2.4.3 Data Playback
This function allows playback of recorded BIN files. When a recorded file is created, a BIN file is generated in the "recordFile" folder within the installed software path.
Recorded data playback method:
- Disconnect the sensor.
- Click the "File" button and then select "Load".
A screenshot shows the WitMotion software's "File" menu with "Load" selected, and a file explorer window open to the "recordFile" directory, displaying a list of .BIN files.
Step 3: Choose the original installation path of the software and load the BIN file.
Step 4: Click "Run". The binary file will play back, and the playback rate can be edited.
A screenshot shows the WitMotion software during data playback. The "ReadFile" window is open, and the main interface displays angle readings (X: 44.48°, Y: -77.02°, Z: 156.02°) during playback.
2.4.4 Standby and Wake Up
Sleep: The module pauses operation and enters standby mode, reducing power consumption.
Wake Up: The module returns to its working state from standby mode.
The module defaults to a working state. To enter sleep state, click the "Sleep" option in the "Config" menu. Click "Sleep" again to release sleep.
A screenshot of the "JY61-Config" window shows the "Sleep" button highlighted, indicating where to activate or deactivate the sleep mode.
2.4.5 Placement Direction
The default installation direction is horizontal. Vertical installation can be configured.
- Rotate the module 90 degrees around the X-axis.
- Place the sensor vertically.
- Click "Vertical" in the "Config" menu under installation directions.
A screenshot of the "JY61-Config" window shows the "Direction" dropdown menu with "Horizontal" selected. The user would change this to "Vertical" for vertical installation.
2.4.6 Static Threshold
Static threshold: When the module is stationary, the gyroscope's measured angular velocity changes slightly. The static threshold function ensures that if the angular velocity is below this threshold, the module outputs 0 angular velocity.
Setting method: Click the "Still Threshold" option in the PC software's configuration bar to set the threshold. The default value is 0.122°/s.
A screenshot of the "JY61-Config" window shows the "Static Threshold" input field with the default value "0.122°/s" displayed.
2.4.7 Bandwidth
The default bandwidth is 10Hz.
A screenshot of the "JY61-Config" window shows the "Bandwidth" dropdown menu with "10Hz" selected.
Function:
- A higher bandwidth setting leads to greater fluctuation in the data waveform. Conversely, a lower bandwidth results in smoother data. For example, a bandwidth of 20Hz with an output rate of 5Hz produces a very steady waveform.
- A higher bandwidth setting helps resolve data-repeating issues. For instance, if the bandwidth is set to 20Hz and the retrieval rate is 100Hz, there will be 5 repeating data points. To avoid repeating data, increase the bandwidth to over 100Hz.
Two screenshots illustrate waveform behavior: one showing more fluctuation with a bandwidth of 256Hz and an output rate of 20Hz, and another demonstrating smoother data with a lower bandwidth setting.
3 Use Instructions with Android Phone
For APP configuration details, please refer to Chapter 2.2.
3.1 APP Installation
Install the APK file and grant Location and Storage permissions.
Screenshots show the WITMOTION app installation process on an Android device, including granting permissions for Storage and Location, and a success message.
A screenshot of a file explorer on an Android device shows a list of downloaded files, including "Android APP.zip" and "WT61C User Manual_V1.0.pdf".
3.2 Hardware Preparation
Connecting with an Android smartphone requires a serial cable and a Type-C or Micro-USB converter, depending on the phone's interface.
A table lists PIN definitions: RED (VCC 5V), YELLOW (TX), GREEN (RX), BLACK (GND). A diagram shows a smartphone connected via a USB-C converter and serial cable to a sensor module.
3.3 Connection
Step 1: Install the APK file and grant Storage permission.
Step 2: Connect the sensor with a TTL cable, then connect the cable to the phone via a Type-C converter. Plug the Type-C converter into the phone.
After a successful connection, a notification "Choose an APP for the USB device" will appear, indicating the device has been detected. Selecting "WitMotion" and choosing "JUST ONCE" or "ALWAYS" is optional.
Note: Only the CH340 driver can be detected via the WitMotion APP.
A screenshot of an Android device shows a prompt asking to "Choose an app for the USB device", with "WitMotion" listed as an option.
3.4 APP Usage
Step 3: Open the APP and select "6-axis Series" as the sensor series.
A screenshot of the WitMotion app displays the "Select Module Type" screen, offering options such as "3-axis Series", "6-axis Series", "9-axis Series", "BLE 5.0 Series", and "WT901-WIFI".
Step 4: Select the baud rate: 115200.
A screenshot of the WitMotion app shows a dialog box for selecting the baud rate, with "115200" checked and the "OK" button visible.
After selection, wait a few seconds for the data to display automatically.
Screenshots of the WitMotion app show real-time data, including acceleration and magnetic field charts, and numerical readings for ax, ay, az, |a|, hx, hy, hz, and |h|.
3.5 Calibration (Android App)
3.5.1 Acceleration Calibration
Steps:
- Keep the module horizontally stationary.
- Click the "Calibration" menu.
- Click "Acceleration Calibration" and wait for 3 seconds.
- Verify the result: confirm that there is 1g on the Z-axis acceleration.
A screenshot of the WitMotion app's calibration menu shows "Acceleration Calibration" highlighted.
3.5.2 Reset Z-axis Angle
Steps:
- Keep the module horizontally stationary.
- Click the "Calibration" menu.
- Click "Z axis return to zero" and wait for 3 seconds.
- Check the "Angle Z" data to confirm it is 0°.
A screenshot of the WitMotion app's calibration menu shows the "Z axis return to zero" option.
4 MCU Connection
A wiring diagram illustrates the connection between the WT61C sensor's pins (VCC, TX, RX, GND) and a generic MCU's pins (VCC, TX, RX, GND).
Link to download all sample code
Link to sample code instructions demo
Notice: Sample code for Linux or Python systems is not currently provided.
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