TFS20-L Miniaturized Single Point LiDAR

TFS20-L User Manual

Preface

This user manual contains the introduction, use and maintenance of  TFS20-L LiDAR. Please read this manual carefully before formal use, and  strictly follow the steps described in the manual during use to avoid  product damage, property loss, personal injury or/and violation of product  warranty terms.

If you encounter problems that cannot be solved during use, please  contact Benewake staff for assistance.

Contact Details

Official website: en.benewake.com

For technical questions, please contact: support@benewake.com

For sales inquiries or to request brochure, please contact:  bw@benewake.com

Contact number: +86-135 8178 8602

Headquarter Address
Benewake (Beijing) Co., Ltd.
3rd Floor, Haiguo Jiaye Sci-Tech Park, Haidian District, Beijing, China

Copyright Notice

This User Manual is copyright © of Benewake. Please do not modify, delete  or translate the description of this manual contents without the official  written permission from Benewake.

Disclaimer

The TFS20-L product is constantly being improved, and its specifications  and parameters will undergo iterative changes. Please refer to the official  website for latest version.

1 Product Overview

This chapter mainly introduces the measuring principle, technical
specifications, structural description, equipment coordinates and field of
view distribution of the TFS20-L LiDAR.

1.1 Measuring principle

TFS20-L is a miniaturized single-point LiDAR module that measures
distance based on direct measurement of time of flight (dToF). The laser at
the transmitting end collimates and emits a pulsed laser signal through the
transmitting lens. After being reflected by the object being measured, the
echo signal enters the receiving lens and is detected by the high-sensitivity
SPAD detector at the receiving end. The time difference between the
transmission and echo signals can be calculated, and the distance
between the object being measured and the LiDAR can be calculated
based on the speed of light.

1.2 Technical specifications

Table. 1: Technical specifications

Performance Parameter

Detection Range

0.2-20m@90% reflectivity@0Klux, 0.2-15m@90% reflectivity@100Klux 0.2-12m@10% reflectivity@0Klux, 0.2-9m@10% reflectivity@100Klux

Accuracy

±6cm(0.2~6m), 1%(≥6m)

Repeatability

2cm(0.2~6m) @1σ

Frame rate

0/ 20 / 50 / 100 (default) / 250Hz

Ambient light  

resistance

100KLux

Laser Parameters

Light source

VCSEL

Central wavelength

905nm

FoV

<2°

Eye safety

Class 1 Eye-safe [EN60825]

Mechanical/Electrical

Average power  

consumption

≤0.35W

Peak current

115mA@3.3V

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Power supply

DC 3.3±9%V

Communication level

LVTTL (3.3V)

Operating  

temperature

-20℃ ~ +60

Storage temperature

-20℃ ~ +85

Dimensions

TYP. 21.0 x 15 x 7.87mm³

Weight

1.35g

Connector

0.8mm-6P (Model: WF08006-01207)

Protection Level

N/A

Communication Protocol

Communication  

Interface

UART/IIC

NOTICE  

① The accuracy is based on reflectivity condition, and any changes in environmental conditions may cause changes in the measurement results.

② The repeatability is based on indoors and reflectivity condition, and any changes in environmental conditions may cause changes in the measurement results.

③ The peak current is measured at room temperature.

1.3 Structural appearance

The overall appearance of the LiDAR is as shown in the figure below: 

Figure. 1: TFS20-L Dimensions

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2 Hardware Interface and Protocol

This section introduces the hardware and protocol information of TFS20-L  LiDAR.

2.1 Pin sequence description

The connector terminal model is WF08006-01207, and the terminal spacing  is 0.8mm.

pinFigure. 2: TFS20-L pin sequence

Pin number

Function

Explanation

3V3 Laser

Laser power  

supply

3V3GND

UART_TX/I2C_SDA 

Transmit / Data

UART_RX/I2C SCL

Receive / Clock

GPIO

Communication  chip select

GND

Ground

The module supports two communication modes: UART and IIC. However,  when powered on, only one interface can be selected for operation.

UART

IIC

Connect the INT pin to ground when  powering on.

When powered on, the INT pin  needs to be pulled up with a 4.7K  resistor or left floating.

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2.2 Serial data communication

Table. 2: Characteristics of UART

Parameter

Default

Configurability

Baud rate

115200

Configurable

Data bit

8

Non

configurable

Stop bit

1

Non

configurable

Parity

None

Non

configurable

NOTICE  

The baud rate can be set to . The default baud rate of TFS20-L is  When the wrong baud rate is configured, it is reset to  

2.3 Serial port output format

Each data packet consists of 9 bytes of hexadecimal numbers, see the  following table for details:

Table. 3: Data-packet Format

Byte0-1

Byte2

Byte3

Byte4

Byte5

Byte6

Byte7

Byte8

Dist_L

Dist_H

Strength

_L

Strength

_H

Temp

_L

Temp

_H

Checksum

Data code explanation

Byte0

0x59, frame header, same for each frame

Byte1

0x59, frame header, same for each frame

Byte2

Dist_L distance value low 8 bits

Byte3

Dist_H distance value high 8 bits

Byte4

Strength_L low 8 bits

Byte5

Strength_H high 8 bits

Byte6

Temp low 8 bits

Byte7

Temp high 8 bits

Byte8

Checksum is the lower 8 bits of the cumulative sum of number of first  8 bytes

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3 Custom Configuration
3.1 Frame definition

Customers can customize some parameters of TFS20-L, such as data  frame format, frame rate, etc., which can be changed by sending specific  commands. All parameters will be saved in Flash after successful  configuration, and there is no need to configure them again when  powering on again.

Please follow specific formats and rules when configuring parameters and avoid sending random commands.

Note: All configuration commands are sent in hexadecimal (HEX).

Table. 4: TFS20-L command format

Byte0

Byte1

Byte2

Byte3 ~ ByteN-2

ByteN-1

Head

Len

ID

Payload

Checksum

Command encoding explanation

Byte0

Header: Fixed to 0x5A

Byte1

Len: The length of the command frame (unit: Byte)

Byte2

ID: Identifies the function of each command

Byte3-N-2

Data: Different meanings and lengths in different ID command  frames

ByteN-1

Checksum: the lower 8 bits of the sum of the first N-2 bytes

3.2 Custom configuration

TFS20-L released several configuration parameters. These parameters,  such as data format, frame rate, could be modified by certain command.  All the parameters will be stored in flash after configured successfully and  customers don’t need to configure again when restart.

Please change the parameter according to certain requirements and do  not frequently try irrelevant instructions. Please configure the product  according to the requirements of the datasheet and don’t send unstated  command.

To set the relevant parameters of TFS20-L, first connect TFS20-L to PC. For  the connection method, refer to sub-section 4.2. Send relevant configuration instructions to the sensor through TF GUI software or other  serial port debugging software; customers can also send relevant  instructions through their own serial port tools.

After sending the parameter configuration instructions, the power needs to  be turned off and settings are saved as default.

Table. 5: General Parameter Configuration and Description

Description

Command

Response

Remarks

Default  

settings

Frame  

rate 

5A 04 01 5F

5A 06 03 LL HH  SU

Only supports  

0/20/50/100/25 0 Hz

100Hz

Instruction  trigger  

mode

5A 04 04 62

Data packet

After setting the  output frame  

rate to 0, you  

can trigger the  sensor through  this command

/

Output  

format

5A 05 05 01 65

5A 05 05 01 65

Standard 9 bytes  (cm)

5A 05 05 06 6A

5A 05 05 06 6A

Standard 9 bytes  (mm)

/

Output  

control 

On: 5A 05 07 01  67 

Off: 5A 05 07  

00 66

Same as  

command

/

Enabled

Modify  

baud rate 

5A 08 06 H1 H2  H3 H4 SU

Same as  

command

Set the baud  

rate Example:  

256000(DEC)=3E 800(HEX), H1=00,  H2=E8, H3=03,  

H4=00

115200

Enable  

checksum

On: 5A 05 08 01  68 

Off: 5A 05 08  00 67

Same as  

command

Enable

Disable

/

Signal

5A 07 22 XX LL

Same as

Example: After

When

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strength  

low  

threshold  

and low  

threshold  

output  

value

HH 00

command

Strength≤100,  

the Dist output  value is changed  to 1200.

XX=100/10=10(DE C)=0A(HEX)

1200(DEC)=4B0( HEX)

LL=B0HH=04

Strength is  

less than  

300, the

Dist output  

value is 500

CAUTION  

① This command is mainly used to adjust the output frequency of the  sensor. The default value of the output frequency is 100Hz, and custom  configuration is supported, supporting frequencies are 0, 20, 50, 100, and  250Hz.

② The baud rate can be set to 9600, 19200, 38400, 57600, 115200,  230400, 460800, 921600. The default baud rate of TFS20-L is 115200. When  the wrong baud rate is configured, it is reset to 115200.

③ An enable data-output command must be sent each time the power is  turned on.

④ ‘SU’ stands for checksum and puts the lower 8 bits into the command. ⑤ There is no need to send the save settings command. Sending a  specific configuration command will take effect and be saved immediately.

For example, to change the baud rate to 460800, first change 460800 to HEX  (0x00 07 08 00), then calculate the checksum to 0x77, and you can get the  following instruction – 5A 08 06 00 08 07 00 77.

Do not send the command that is not in the list above.

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4 Quick Test Guide
4.1 Tools required for test

tools

converter

cable

pc

software

TFS20-L

TTL-USB converter

USB cable

PC

Test Software

4.2 Test procedures

(1) Download the test software

Download the latest version of test software for TFS20-L from Benewake  official website:  

https://en.benewake.com/DataDownload/index_pid_20_lcid_99.html

Note: Please turn off the anti-virus software before decompressing the  host computer software to avoid the files in the host computer software  being deleted as viruses. The host computer currently only supports running  on Windows systems.

(2) Connection of the hardware

testFigure. 3: LiDAR and PC interfacing

Connect “TFS20-L”, “TTL-USB board” and “USB cable”. Make sure there is  no loose connection. Then connect “USB cable” with “PC”. As shown in the  above image.

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(3) Connection with software

Run GUI software, select “① TFmini/TFmini-S” and select automatically  recognized communication port (here it is “② COM9”), choose the right  baud rate (here it is “③ 115200”), as shown in the following image.

baud rateFigure. 4: GUI software and LiDAR interfacing

Then click “CONNECT”. Upon successful connection, the continuous graph  of the output data will be displayed in area “④ TIME LINE CHART”. Besides,  the real-time data of the current measured distance (Dist), effective data  points per second (Effective Points) and signal strength (Strength) will be  displayed in area “⑤ REAL TIME DATA”.

Note 

① If no data is available in area “TIME LINE CHART”, please check the wire connection and sequence. When  TFS20-L is successfully powered on, there will be a faint red  light inside transmitting lens viewing from the front using  mobile phone camera or any other IR light detecting device.

② The value of distance output Dist may vary with the output unit, which is cm by default. If the unit of distance is  changed to the unit-mm with specific command, and the PC  software will be unable to identify it, and so the unit of  “TIME LINE CHART” will still be cm. For example, the actual

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TFS20-L measurement is 1m, the distance value of TFS20-L  is 1000 in mm, the value read by the PC software also is  1000, but the unit will not change and still display cm.

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5 Q&A

① After the LiDAR is connected to the host computer, there is no data  output.

Cause-1: TTL-USB board connection is bad.

Solution: Check whether the connection between TTL-USB board, TFS20-L  and PC is correct and reliable.

Cause-2: The serial port driver is not installed correctly.

Solution: Re-plug the USB cable and try to re-install the driver, or search  the Internet for the driver to download and install. If you still cannot use the  host computer normally, please contact our technical support.

② TFS20-L will heat up after working for a period of time. Explanation: This is the normal working state of the product. After the chip  and circuit board continue to work, slight heating is normal.

③ TFS20-L has no data output.

Cause-1: The V1.40C version does not output data by default when  powered on, and you need to send an output enable command (as  mentioned in Table 5).

Solution: Send the output enable command 5A 05 07 01 67 after powering  on.

Cause-2: The product will be strictly inspected before leaving our factory,  ensuring that all the shipped products can work normally. However, some  abnormal working matters maybe still occur because of incidents during  the transportation or use.

Solution: Check whether the power supply is normal and whether the  voltage is within the rated voltage range. If the power supply is normal,  there should be a faint red light in the TFS20-L transmitting lens. Check whether the wiring sequence of TFS20-L is correct and whether the  connection is reliable.

Check whether the data parsing is correct. Please parse it according to the  data format described in the manual.

If the problem is still not solved, please contact technical support.

④ Does TFS20-L support ultra-low power mode?

Answer: No, it does not support. The current standby power consumption is  about 145 mW. The average power consumption is about 350 mW. If  powered by a 10000mAh battery, it can last about 6 days.

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Documents / Resources

Benewake TFS20-L Miniaturized Single Point LiDAR [pdf] User Manual
TFS20-L, TFS20-L Miniaturized Single Point LiDAR, Miniaturized Single Point LiDAR, Single Point LiDAR, Point LiDAR, LiDAR

References

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