wt61c digital ahrs sensor specification · 2019-09-11 · wt61c digital ahrs sensor specification...

https://wiki.wit-motion.com/english

WhatsApp:+86 13652339539 E-mail：[email protected] Web：https://wiki.wit-motion.com/english- 1 -

WT61C Digital AHRS Sensor

SPECIFICATION

Model ： WT61C

Description ：6 Axis Digital Attitude Angle Sensor With Case

Quality control system standard: ISO9001:2016

Tilt switch production standard：GB/T191SJ 20873-2016

Criterion of detection：GB/T191SJ 20873-2016

Revision date：2019.09.09

Download Link(software, manual, etc.):

https://drive.google.com/file/d/1o-bcjaoml6dNeXbMDcYy7-0kfL0J1B3A

https://drive.google.com/file/d/1o-bcjaoml6dNeXbMDcYy7-0kfL0J1B3A



Catalog

1 Description...................................................................................................- 3 -

2 Product parameters...................................................................................... - 4 -

3 Product display............................................................................................ - 5 -

4 Axial direction............................................................................................. - 5 -

5 Connection...................................................................................................- 6 -

5.1 Serial connection...............................................................................- 6 -

5.2 calibration(calibration on PC software).......................................... - 11 -

5.2.1 Z-axis to 0................................................................................- 11 -

5.2.2 Accelerometer calibration....................................................... - 12 -

5.3 Data recording.................................................................................- 12 -

5.4 Installation direction........................................................................- 13 -

5.5 Dormancy and break dormancy...................................................... - 15 -

5.6 Static threshold and measure width.................................................- 15 -

5.7 Connect to Phone............................................................................ - 17 -

6 Communication protocol........................................................................... - 22 -

6.1 PC software to module.................................................................... - 22 -

6.2 Module to PC software....................................................................- 22 -

6.2.1 Acceleration output................................................................. - 23 -

6.2.2 Angular velocity output...........................................................- 23 -

6.2.3 Angle output............................................................................- 24 -

6.3 Date analysis and sample code........................................................- 25 -

6.4 Data analysis sample in embedded environment............................ - 26 -

7 Application area.........................................................................................- 29 -



1 Description The purpose of this six axis gyro acceleration module uses high precision MPU6050

module, measuring data by the processor reads the MPU6050 and then output through the

serial port, and elaborate PCB layout and process to ensure that the MPU6050 received the

minimum interference with the highest measurement accuracy.

An internal voltage stabilizing circuit module, voltage 3.3v~5v, pin compatible with the

3.3V/5V embedded system, convenient connection.

The advanced digital filtering technology of this product can effectively reduce the

measurement noise and improve the 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.

Note: This module does not contain magnetometer, can not be tested with the yaw angle,

so yaw angle is calculated by integration, it will drift, the yaw angle is accurate only in a

short time. The X, Y axis angle is accurate because it can be filtered by gravity field, it will not

drift.



2 Product parameters

1) Voltage: 3.3V-5V

2) Current: <40mA

3) Size : 51.3mm x 36mm X 15mm

4) Measuring dimensions: Acceleration:3D Angular Velocity: 3D Attitude

Angle:2D(Roll Pitch)

5) Range : Acceleration : ±16g Angular Velocity : ±2000°/s Angle: (X±180°,Y±

90°)

6) Resolution: Acceleration:0.0005g , Angular velocity: 0.61°/s.

7) Stability: Acceleration : 0.01g Angular Velocity : 0.05°/s

8) Attitude measurement stability: 0.01°

9) Output content: Time, Acceleration , Angular Velocity ,Tilt Angle

10) Data output frequency:100Hz(baudrate115200)/20Hz(9600baud).

11) Data interface: Serial port(TTL/RS232).

12）Baud rate: 9600,115200(default).



3 Product display

4 Axial direction

As shown in figure above, The axis of the module is in the upper picture, upward

for x-axis, to the left for y-axis, Perpendicular to the paper, outward to the z-axis,

The direction of rotation is defined by the Law of the right hand. That is to say the

direction of four-fingers bending is the direction of rotation around the axis. The

thumb of the right hand points to axis.



5 Connection

5.1Serial connection

Module 3 in 1 Convert:

Driver installation:

First, install the driver CH340 when we used the USB serial module ,after installed

the driver. then get the corresponding Com number in the device manager. Driver

as followed:

https://wiki.wit-motion.com/english/doku.php?id=communication_module




Module 6 in 1 Convert:

Driver installation:

First, install the driver CP210X when we used the USB serial module ,after installed

the driver. then get the corresponding Com number in the device manager. Driver

as followed:





After installing the module driver, and then Device Manager can query corresponding



serial number, as below figure shows:

Connect with PC software

Open the software “MiniIMU.exe” and select the Com number

which you have got in the device manager before.

Click the menu “Type” , Select the model as “JY61” in the software.



Click the menu “Baud ”in the software and then select 115200, then the software

will show the data.



5.2calibration(calibration on PC software)

5.2.1 Z-axis to 0

The module should be calibrated before you use it. The module calibrate includes

Z-axis to 0 ,Accelerometer calibration.

The z axis is 0 is the module z axis angle initial state is relative 0 degree angle

When the module is used before and z - axis drift is large, the z - axis can be

calibrated



5.2.2 Accelerometer calibration

The accelerometer calibration is used to get rid of the null bias of the

accelerometer. There will be different degrees of null bias in the sensors when they

firstly came out of the factory.

The calibration method is as follows:

Firstly, the module is kept horizontal and static, and the calibration is added. After

1 to 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°. The X Y-axis angle is more accurate

after calibration.

5.3 Data recording

There is no memory chip inside the sensor module，but the data can be saved by

PC software

Attention：The button”Record” can save the data as a file.



The saved files in the PC software Data.tsv：

5.4 Installation direction

The default installation direction of the module is horizontal installation. When the

module needs to be placed vertically, you can use the vertical installation setting.

Vertical installation method：Rotate the module around the X-axis and place it 90



degrees vertical when installing vertically ， Select the “vertical” in the “Config”

of the PC software.

Once the setting are completed, calibrate them to use.



5.5 Dormancy and break dormancy

Dormancy：The module pauses working and enters the standby state, dormancy

can reduce power consumption.

Break dormancy：The module enters the working state from the standby state.

How to use：The default state of the module is working state，Click “Sleep”in the

“config”of the PC software to enter the standby state, click “Sleep” again the

module will break the dormancy.

5.6 Static threshold and measure width

Static threshold ： The angular velocity of the gyroscope chip is slightly change

when the module is in static placement. The effect of the “Static threshold” is

When the angular velocity is less than the threshold module output angular

velocity is 0.



Bandwidth ： The module output the data within the measurement bandwidth.

Data greater than bandwidth is automatically filtered out.

How to use：Click the “Bandwidth ”of the “config ” in the PC software. default

is 10 HZ.



PS: The default setting of Static threshold and bandwidth works in most case. you

should not set it any more.

5.7 Connect to Phone

1) Install the app in the Phone by the link as below:

https://drive.google.com/open?id=1KrE0iPXsJpt2kNleUzTH3cZHkTYzwpPH

1)We use OTG drive to connect to phone

2)Then open the app and choose WT601



3) choose 115200



Then the data will show

4) Calibration(calibration on App)

Please keep the WT61C on the horizontal level and make the “acceleration

calibration” and “Z axis return to zero” as below:



1) Accelerometer Calibration

The accelerometer calibration is used to remove the zero bias of the

accelerometer. When the sensor is out of the factory, there will be different

degrees of bias error. After manual calibration, the measurement will be

accurate.

1、Methods as below: Firstly keep the module horizontally stationary, click

“Acceleration”, after 1~2s the acceleration X Y Z value will at 0 0 1. X Y angle:

0°.After calibration the value will be accurate.

2) Z axis return to zero

Just click the z axis return to zero, then the data will show.



6 Communication protocol

Level：TTL level

Band rate：115200，Stop bit 1，check digit 0。

6.1 PC software to module

Introductions：

1.When the module is on, it needs to be static first. Because the MCU inside the

module will be aotomatically calibrated when it is in static. After calibration，the

angle of Z-axis will be initialize to 0. Which can be considered as a signal that have

been calibrated.

6.2 Module to PC software

Every frame data that the module sent to the PC software is divided into 3

packets,acceleration pocket, angular velocity packet and angle packet.



6.2.1 Acceleration output

Formula for calculating acceleration：

ax=((AxH<<8)|AxL)/32768*16g(g is gvality acceleration，9.8m/s2)

ay=((AyH<<8)|AyL)/32768*16g(g is gvality acceleration，9.8m/s2)

az=((AzH<<8)|AzL)/32768*16g(g is gvality acceleration，9.8m/s2)

Formula for calculating temperature：

T=((TH<<8)|TL) /340+36.53 ℃

Checksum：

Sum=0x55+0x51+AxH+AxL+AyH+AyL+AzH+AzL+TH+TL

6.2.2 Angular velocity output



Formula for calculating angular velocity:

wx=((wxH<<8)|wxL)/32768*2000(°/s)

wy=((wyH<<8)|wyL)/32768*2000(°/s)

wz=((wzH<<8)|wzL)/32768*2000(°/s)


T=((TH<<8)|TL) /340+36.53 ℃

Checksum：

Sum=0x55+0x52+wxH+wxL+wyH+wyL+wzH+wzL+TH+TL

6.2.3 Angle output

Formula for calculating angle:

Roll angle（x axis）Roll=((RollH<<8)|RollL)/32768*180(°)

The pitching angle（y axis）Pitch=((PitchH<<8)|PitchL)/32768*180(°)



Yaw angle（zaxis）Yaw=((YawH<<8)|YawL)/32768*180(°)


T=((TH<<8)|TL) /340+36.53 ℃

Checksum：

Sum=0x55+0x53+RollH+RollL+PitchH+PitchL+YawH+YawL+TH+TL

Attention：

1. The coordinate system used in the calculation of attitude angle is the northeast

coordinatesystem ， Place the module positivly, left is X-axis, front is X-axis.

upward is Z-axis.When the attitude is expressed by the Euler angle. Coordinate

rotation sequence is Z-Y-X.

6.3 Date analysis and sample code

double a[3],w[3],Angle[3],T;

void DecodeIMUData(unsigned char chrTemp[])

{

switch(chrTemp[1])

{

case 0x51:

a[0] = (short(chrTemp[3]<<8|chrTemp[2]))/32768.0*16;



T = (short(chrTemp[9]<<8|chrTemp[8]))/340.0+36.25;

break;

case 0x52:

w[0] = (short(chrTemp[3]<<8|chrTemp[2]))/32768.0*2000;




break;

case 0x53:



Angle[0] = (short(chrTemp[3]<<8|chrTemp[2]))/32768.0*180;




printf("a = %4.3f\t%4.3f\t%4.3f\t\r\n",a[0],a[1],a[2]);

printf("w = %4.3f\t%4.3f\t%4.3f\t\r\n",w[0],w[1],w[2]);

printf("Angle = %4.2f\t%4.2f\t%4.2f\tT=%4.2f\r\n",Angle[0],Angle[1],Angle[2],T);

break;

}

}

6.4 Data analysis sample in embedded environment

The code is divided into two parts, one of them is interrupt reception. Find the

header of the data and then put the data-packet into an array. The other one is

data analysis, which is put into the main program section.

Interrupt unit(The following is AVR microcontroller code, different MCU reads the

register a little different):

unsigned char Re_buf[11],counter=0;

unsigned char sign;

interrupt [USART_RXC] void usart_rx_isr(void) //USART serial receiving interrupt

{

Re_buf[counter]=UDR; //Different micro-controller is slightly

different

if(counter==0&&Re_buf[0]!=0x55) return; //NO.0 data is not a frame

header ,skip.

counter++;



if(counter==11) //11 data has been received

{ counter=0; // Reassigned,ready for the next frame data reception

sign=1;

}

}

Main program section：

float a[3],w[3],angle[3],T;

extern unsigned char Re_buf[11],counter;

extern unsigned char sign;

while(1)

{

if(sign)

{

sign=0;

if(Re_buf[0]==0x55) //Check the frame header

{

switch(Re_buf [1])

{c

ase 0x51:

a[0] = (short(Re_buf [3]<<8| Re_buf [2]))/32768.0*16;





T = (short(Re_buf [9]<<8| Re_buf [8]))/340.0+36.25;

break;

case 0x52:

w[0] = (short(Re_buf [3]<<8| Re_buf [2]))/32768.0*2000;




break;

case 0x53:

angle[0] = (short(Re_buf [3]<<8| Re_buf [2]))/32768.0*180;




break;

}

}

}



7 Application area

Agricultural machinery Internet of things

Solar energy Power monitoring

Medical instruments Construction machinery

Geological monitoring



WitMotion ShenZhen Co., Ltd

WT61C High Precision Digital Inclinometer

Contact: Mr. Kyle Tsang

E-mail : [email protected]

Skype: live:kyle_8394

WhatsApp: +86 136 523 39539

Amazon in USA: www.amazon.com/witmotion

Amazon in Canada: www.amazon.ca/witmotion

Amazon in Japan: www.amazon.co.jp/witmotion

Official Direct Store: www.aliexpress.com/store/4709011

Address : Honghai building 1405 Songgang town Baoan District

Shenzhen Guangdong Province China

mailto:[email protected]

https://www.amazon.com/witmotion

https://www.amazon.com/witmotion

https://www.amazon.co.jp/witmotion

wt61c digital ahrs sensor specification · 2019-09-11 · wt61c digital ahrs sensor specification...

Documents