WiT WT901BLECL 5.0 User manual

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WT901BLECL Bluetooth 5.0 Gyro Sensor
SPECIFICATION
Model ：WT901BLECL 5.0
Description ：Bluetooth 5.0 AHRS IMU sensor with battery
Quality system standard: ISO9001:2016
Tilt switch production standard：GB/T191SJ 20873-2016
Criterion of detection：GB/T191SJ 20873-2016
Revision date：2019.12.16
Link to WT901BLECL BLE 5.0 tutorial:(software, manual, etc.):
https://drive.google.com/open?id=1TWqkdsXo-yMxBGp3Px6CokytSHNwPS1R
Link to demo video of WT901BLECL BLE 5.0:
https://www.dropbox.com/sh/n5ujs8vswagvqve/AADPVFA_1FA7gAr4aW6T8yMxa?dl=0

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Catalog
1 Description...................................................................................................- 3 -
2 Product Size.................................................................................................- 3 -
3 Features........................................................................................................- 4 -
4 Axial Diron.................................................................................................. - 4 -
5 Method.........................................................................................................- 5 -
5.1 Connect App......................................................................................- 5 -
5.2 Clibration method..............................................................................- 8 -
5.2.1 Acceleration calibration............................................................ - 9 -
5.2.2 Magnetic Calibration.................................................................- 9 -
5.3 Connect to PC software...................................................................- 11 -
5.3.1 Calibration by Instruction........................................................- 15 -
5.4 Restore Factory Setting................................................................... - 15 -
5.5 Sleep/ Wake up................................................................................- 15 -
6 Communication Protocol...........................................................................- 15 -
6.1 Module to APP................................................................................ - 16 -
6.1.1 Acceleration, Angular velocity, Angle, Data pack(default).... - 16 -
6.1.2 Single Return Register Data Packet........................................ - 17 -
6.2 APP to Module................................................................................ - 19 -
6.2.1 Read register value.................................................................. - 19 -
6.2.2 Accelerometer Calibration and Magnetic Calibration............ - 20 -
6.2.3 Save Settings........................................................................... - 20 -
6.2.4 Set Return Rate........................................................................- 20 -
Set Port D0..........................................................................................- 20 -
Set Port D1..........................................................................................- 21 -
Set Port D2..........................................................................................- 21 -
Set Port D3..........................................................................................- 21 -

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6.3 Register address.............................................................................. - 21 -
7. Application Area..........................................................................................- 24 -
1 Description
Module integrates high-precision gyroscope, accelerometer, mpu9250 geomagnetic sensor,
high-performance microprocessors and advanced dynamics solves dynamic Kalman filter
algorithm to quickly solve the current real-time movement of the module attitude .
The use of advanced digital filtering technology, can effectively reduce the measurement
noise and improve measurement accuracy.
Integrates gesture solver, with dynamic Kalman filter algorithm, can get the accurate attitude
in dynamic environment, attitude measurement precision is up to 0.05 degrees with high
stability, performance is even better than some professional Inclinometer!
Integrate voltage stabilization circuit, working voltage is 3.3v ~ 5v, pin level compatible
3.3V and 5V embedded system .
High-performance cortex-M0 core processor runs at up to 50MHz, taking into account low
power consumption and high performance.
BLE 5.0 wireless transmission, transmission stability, distance greater than 50 meters.
Low power consumption, long standby time, self-contained battery.
Stamp hole gold plating process can be embedded in the user's PCB board.
4-layer PCB technology, thinner, smaller, and more reliable.
2 Product Size

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3 Features
1、Voltage：3.3V~5V
2、Working current: ≈15mA, broadcast current: ≈150uA, standby current: 10uA~50uA
3、Volume：51.3 X 36 X 15mm
4、Measuring dimensions:
Acceleration: X Y Z
Angular velocity: X Y Z
Attitude angle:X Y Z
Magnetic field：XYZ
6、Range: Acceleration: ± 16g, Angular velocity: ± 2000 ° / s,Angle:X Z ±180° Y ±90°
7、Stability: Acceleration: 0.01g, Angular speed 0.05° / s.
8、Attitude measurement stable:X Y 0.05° Z :1°
9、Data output: Acceleration, Angular velocity, Angle,Magnetic field, Port status
10、The data output frequency: 0.1Hz ~50Hz (10Hz default)
11、Data Interface: UART(TTL , Baud rate 115200)
12、Expansion port function：Analog input（0~VCC, Digital input, Digital output)
13、Bluetooth transmission distance：>50m
14、BLE 5.0：Support Android /IOS
4 Axial Diron
As shown in the figure above, the coordinates of the module are indicated, and the upper is
the X-axis, the left is Y axis, the Z axis is perpendicular to the surface of the paper to yourself.

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The direction of rotation is defined by the right hand rule. that is, the thumb of the right hand is
pointed to the axial direction, and the four is the direction of the bending of the right hand.
5 Method
5.1 Connect App
Android App
1. The module builds with a battery,open switch on the side, and open the APP search
directly. If you can't find the module, the battery may be out of power. Plug in the data cable
and try again.
2. Open the mobile app and click “Scan” to start searching for Bluetooth. The Bluetooth
name is “WT901BLE50”.

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3. Click on the Bluetooth name, the APP cuts into the data display window, and you can see
the data returned by the module.

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5.1.1 iOS app
Link to app: https://cw.pub/vrn5
Step 1: Open link by safari and download the app

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Step 2: Find device management and trust the app launcher.
The connection with IOS app has been shown as below:
5.2 Clibration method
The module needs to be calibrated before it can be used. Calibration of the module includes
additional calibration, magnetic field calibration.

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5.2.1 Acceleration calibration
The addition calibration is used to remove the zero offset of the accelerometer. The sensor
will have different degrees of zero offset error at the factory, and the measurement will be
accurate after manual calibration.
1. To add calibration, the method is as follows: Firstly, keep the module horizontally
stationary, click to add calibration, after 1~2 seconds, the three axial values of the module
acceleration will be around 0 0 1 and the X and Y axis angles will be around 0°. After
calibration, the X Y-axis angle is accurate.
5.2.2 Magnetic Calibration
Magnetic field calibration is used to remove the magnetic field sensor's zero offset. Usually,
the magnetic field sensor will have a large zero error when it is manufactured. If it is not
calibrated, it will bring about a large measurement error and affect the accuracy of the Z-axis
angle measurement of the heading angle.
Calibration methods as follow:
1. When calibrating, first connect the module and the computer, and place the module in a
place far away from the disturbing magnetic field (ie, more than 20 CM away from magnets and
iron, etc.), and then open the upper computer software.
2. Click the “Magnetic Field Calibration”and rotate 360°around the X axis of the module
( you can rotate around the Y axis or the Z axis first). Rotate a few turns, then turn 360°around

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the Y axis. Then turn 360°around the Z axis, then turn a few turns at random, then click the
“Finish” to complete the calibration.
1. Click the “Save” button to save the zero offset data to the internal FLASH of the module.
Thereafter, the module is able to output an accurate heading angle.
Note: The data displayed on the APP will not change when the calibration is completed.