Table of Contents:

1. Introduction

1.1 What is LDS12-NB NB-IoT LiDAR ToF Distance Sensor

The Dragino LDS12-NB is a NB-IoT LiDAR ToF (Time of Flight) Distance Sensor for Internet of Things solution. It is capable to measure the distance to an object as close as 10 centimeters (+/- 5cm up to 6m) and as far as 12 meters (+/-1% starting at 6m)!. The LiDAR probe uses laser induction technology for distance measurement.

The LDS12-NB can be applied to scenarios such as horizontal distance measurement, parking management system, object proximity and presence detection, intelligent trash can management system, robot obstacle avoidance, automatic control, sewer, etc.

It detects the distance between the measured object and the sensor, and uploads the value via wireless to NB-IoT IoT Server.

LDS12-NB supports different uplink methods including MQTT, MQTTs, UDP & TCP for different application requirement, and support uplinks to various IoT Servers.

LDS12-NB supports BLE configure and OTA update which make user easy to use.

LDS12-NB is powered by 8500mAh Li-SOCI2 battery, it is designed for long-term use up to several years.

LDS12-NB has optional built-in SIM card and default IoT server connection version. Which makes it works with simple configuration.


1.2 ​Features

  • NB-IoT Bands: B1/B2/B3/B4/B5/B8/B12/B13/B17/B18/B19/B20/B25/B28/B66/B70/B85 @H-FDD
  • Ultra-low power consumption
  • Laser technology for distance detection
  • Measure Distance: 0.1m~12m
  • Accuracy :  ±5cm@(0.1-5m), ±1%@(5m-12m)
  • Multiply Sampling and one uplink
  • Support Bluetooth v5.1 remote configure and update firmware
  • Uplink on periodically
  • Downlink to change configure
  • IP65 Waterproof Enclosure
  • 8500mAh Battery for long term use
  • Nano SIM card slot for NB-IoT SIM

1.3 Specification

Common DC Characteristics:

  • Supply Voltage: 2.5v ~ 3.6v
  • Operating Temperature: -40 ~ 85°C

Probe Specification:

  • Storage temperature:-20°C ~ 75°C
  • Operating temperature : -20°C ~ 60°C
  • Measure Distance:
    • 0.1m ~ 12m @ 90% Reflectivity
    • 0.1m ~ 4m @ 10% Reflectivity
  • Accuracy : ±5cm@(0.1-5m), ±1%@(5m-12m)
  • Distance resolution : 1cm
  • Ambient light immunity : 70klux
  • Enclosure rating : IP65
  • Light source : LED
  • Central wavelength : 850nm
  • FOV : 3.6°
  • Material of enclosure : ABS+PC
  • Wire length : 25cm

NB-IoT Spec:

NB-IoT Module: BC660K-GL

Support Bands:

  • B1 @H-FDD: 2100MHz
  • B2 @H-FDD: 1900MHz
  • B3 @H-FDD: 1800MHz
  • B4 @H-FDD: 2100MHz
  • B5 @H-FDD: 860MHz
  • B8 @H-FDD: 900MHz
  • B12 @H-FDD: 720MHz
  • B13 @H-FDD: 740MHz
  • B17 @H-FDD: 730MHz
  • B18 @H-FDD: 870MHz
  • B19 @H-FDD: 870MHz
  • B20 @H-FDD: 790MHz
  • B25 @H-FDD: 1900MHz
  • B28 @H-FDD: 750MHz
  • B66 @H-FDD: 2000MHz
  • B70 @H-FDD: 2000MHz
  • B85 @H-FDD: 700MHz


  • Li/SOCI2 un-chargeable battery
  • Capacity: 8500mAh
  • Self Discharge: <1% / Year @ 25°C
  • Max continuously current: 130mA
  • Max boost current: 2A, 1 second

Power Consumption

  • STOP Mode: 10uA @ 3.3v
  • Max transmit power: 350mA@3.3v

1.4 Applications

  • Horizontal distance measurement
  • Parking management system
  • Object proximity and presence detection
  • Intelligent trash can management system
  • Robot obstacle avoidance
  • Automatic control
  • Sewer

1.5 Sleep mode and working mode

Deep Sleep Mode: Sensor doesn't have any NB-IoT activate. This mode is used for storage and shipping to save battery life.

Working Mode: In this mode, Sensor will work as NB-IoT Sensor to Join NB-IoT network and send out sensor data to server. Between each sampling/tx/rx periodically, sensor will be in IDLE mode), in IDLE mode, sensor has the same power consumption as Deep Sleep mode.

1.6 Button & LEDs


Behavior on ACTFunctionAction
Pressing ACT between 1s < time < 3sSend an uplink

If sensor has already attached to NB-IoT network, sensor will send an uplink packet, blue led will blink once.
Meanwhile, BLE module will be active and user can connect via BLE to configure device.

Pressing ACT for more than 3sActive Device

Green led will fast blink 5 times, device will enter OTA mode for 3 seconds. And then start to  attach NB-IoT network.
Green led will solidly turn on for 5 seconds after joined in network.
Once sensor is active, BLE module will be active and user can connect via BLE to configure device, no matter if device attach NB-IoT network or not.

Fast press ACT 5 times.Deactivate DeviceRed led will solid on for 5 seconds. Means device is in Deep Sleep Mode.

Note: When the device is executing a program, the buttons may become invalid. It is best to press the buttons after the device has completed the program execution.

1.7 BLE connection

LDS12-NB support BLE remote configure and firmware update.

BLE can be used to configure the parameter of sensor or see the console output from sensor. BLE will be only activate on below case:

  • Press button to send an uplink
  • Press button to active device.
  • Device Power on or reset.

If there is no activity connection on BLE in 60 seconds, sensor will shut down BLE module to enter low power mode.

1.8 Pin Definitions , Switch & SIM Direction


1.8.1 Jumper JP2

Power on Device when put this jumper.

1.8.2 BOOT MODE / SW1

1) ISP: upgrade mode, device won't have any signal in this mode. but ready for upgrade firmware. LED won't work. Firmware won't run.

2) Flash: work mode, device starts to work and send out console output for further debug

1.8.3 Reset Button

Press to reboot the device.

1.8.4 SIM Card Direction

See this link. How to insert SIM Card.

1.9 Mechanical




Probe Mechanical:


2. Use LDS12-NB to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT network

The LDS12-NB is equipped with a NB-IoT module, the pre-loaded firmware in LDS12-NB will get environment data from sensors and send the value to local NB-IoT network via the NB-IoT module.  The NB-IoT network will forward this value to IoT server via the protocol defined by LDS12-NB.

Below shows the network structure:


There are two version: -GE and -1D version of LDS12-NB.

GE Version: This version doesn't include SIM card or point to any IoT server. User needs to use AT Commands to configure below two steps to set LDS12-NB send data to IoT server.

  • Install NB-IoT SIM card and configure APN. See instruction of Attach Network.

Below shows result of different server as a glance.

ServersDash BoardComments




General UDPRaw Payload. Need Developer to design Dash Board 
General MQTTRaw Payload. Need Developer to design Dash Board 





1D Version: This version has 1NCE SIM card pre-installed and configure to send value to DataCake. User Just need to select the sensor type in DataCake and Activate LDS12-NB and user will be able to see data in DataCake. See here for DataCake Config Instruction.

2.2 ​Payload Types

To meet different server requirement, LDS12-NB supports different payload type.


User can specify the payload type when choose the connection protocol. Example:

AT+PRO=2,0            // Use UDP Connection & hex Payload

AT+PRO=2,5            // Use UDP Connection & Json Payload

AT+PRO=3,5            // Use MQTT Connection & Json Payload

2.2.1 General Json Format(Type=5)

This is the General Json Format. As below:

{"IMEI":"863663062798914","Model":"LDS12-NB","ds18b20_temperature":-0.1,"distance":248,"distance_signal_strength":619,"temperature":26,"interrupt":0,"interrupt_level":0,"battery":3.39,"signal":13,"1":[248,629,26,"2024/05/28 07:26:39"],"2":[253,586,26,"2024/05/28 07:25:39"],"3":[254,565,26,"2024/05/28 07:24:39"],"4":[258,518,26,"2024/05/28 07:23:39"],"5":[251,591,26,"2024/05/28 07:22:39"],"6":[314,293,26,"2024/05/28 07:21:39"],"7":[324,279,25,"2024/05/28 07:20:39"],"8":[335,262,25,"2024/05/28 07:19:52"]}


Notice, from above payload:

  • DS18b20_temperature, Distance, Distance_signal_strength, Temperature, Interrupt, Interrupt_level, Battery & Signal are the value at uplink time.
  • Json entry 1 ~ 8 are the last 1 ~ 8 sampling data as specify by AT+CLOCKLOG=1,65535,15,8  Command. Each entry includes (from left to right): Distance, Distance signal strength, LIDAR Temperature, Sampling time.

2.2.2 HEX format Payload(Type=0)

This is the HEX Format. As below:



If we use the MQTT client to subscribe to this MQTT topic, we can see the following information when the NB sensor uplink data.



These bytes include the hardware and software version.

Higher byte: Specify Sensor Model: 0x0F for LDS12-NB

Lower byte: Specify the software version: 0x7b=123, means firmware version 1.2.3

BAT (Battery Info):

Ex1: 0x0DB4 = 3508mV

DS18B20 Temperature sensor:

This is optional, user can connect external DS18B20 sensor to the +3.3v, 1-wire and GND pin . and this field will report temperature.


If payload is: 0105H:  (0105 & FC00 == 0), temp = 0105H /10 = 26.1 degree

If payload is: FF3FH :  (FF3F & FC00 == 1) , temp = (FF3FH - 65536)/10 = -19.3 degrees.


Represents the distance value of the measurement output, the default unit is cm, and the value range parsed as a decimal number is 0-1200. In actual use, when the signal strength value Strength.


If the data you get from the register is 0x0B 0xEA, the distance between the sensor and the measured object is 0BEA(H) = 3050 (D)/10 = 305cm.

Distance signal strength:

Refers to the signal strength, the default output value will be between 0-65535. When the distance measurement gear is fixed, the farther the distance measurement is, the lower the signal strength; the lower the target reflectivity, the lower the signal strength. When Strength is greater than 100 and not equal to 65535, the measured value of Dist is considered credible.


If payload is: 01D7(H)=471(D), distance signal strength=471, 471>100,471≠65535, the measured value of Dist is considered credible.

Customers can judge whether they need to adjust the environment based on the signal strength.

Interrupt Pin:

This data field shows if this packet is generated by interrupt or not.

Note: The Internet Pin is a separate pin in the screw terminal. 


If byte[0]&0x01=0x00 : Normal uplink packet.

If byte[0]&0x01=0x01 : Interrupt Uplink Packet.

Interrupt Level:

This byte shows whether the interrupt is triggered by a high or low level.

Ex1: 0x00  Interrupt triggered by falling edge (low level)

Ex2: 0x01  Interrupt triggered by rising edge (high level)

LiDAR temp:

Characterize the internal temperature value of the sensor.


If payload is: 001C(H) <<24>>24=28(D), LiDAR temp=28°C.

If payload is: FFF2(H) <<24>>24=-14(D), LiDAR temp=-14°C.

2.2.3 ThingsBoard Payload(Type=3)

Type3 payload special design for ThingsBoard, it will also configure other default server to ThingsBoard.

    "topic": "2276492",
    "payload": {
        "IMEI": "863663062798914",
        "Model": "LDS12-NB",
        "ds18b20_temperature": -0.1,
        "distance": 283,
        "distance_signal_strength": 369,
        "temperature": 25,
        "interrupt": 0,
        "interrupt_level": 0,
        "battery": 3.38,
        "signal": 14,
        "1": [288, 362, 25, "2024/05/27 05:46:59"],
        "2": [283, 365, 24, "2024/05/27 05:40:52"],
        "3": [287, 366, 24, "2024/05/27 05:37:52"],
        "4": [288, 348, 24, "2024/05/27 05:34:52"],
        "5": [292, 335, 24, "2024/05/27 05:31:52"],
        "6": [297, 333, 24, "2024/05/27 05:28:52"],
        "7": [295, 332, 24, "2024/05/27 05:25:52"],
        "8": [295, 338, 24, "2024/05/27 05:22:52"]


2.2.4 ThingSpeak Payload(Type=1)

This payload meets ThingSpeak platform requirement. It includes six fields. Form1~6are:

Distance, Distance signal strength, Temperature, Battery, Signal&DS18b20 temperature, This payload type only valid for ThingsSpeak Platform.

As below:

field1=Distance value&field2=Distance signal strength value&field3=Temperature value&field4=Battery value&field5=Singal value&field6=DS18b20 temperature value


2.3 Test Uplink and Change Update Interval

By default, Sensor will send uplinks every 2 hours 

User can use below commands to change the uplink interval.

AT+TDC=600        // Set Update Interval to 600s

User can also push the button for more than 1 seconds to activate an uplink.

Notice: The AT+NOUD feature is upgraded to Clock Logging, please refer Clock Logging Feature

To save battery life, LDS12-NB will sample distance data every 15 minutes and send one uplink every 2 hours. So each uplink it will include 8 stored data + 1 real-time data. They are defined by:

  • AT+TR=900        // The unit is seconds, and the default is to record data once every 900 seconds (15 minutes, the minimum can be set to 180 seconds)
  • AT+NOUD=8     //  The device uploads 8 sets of recorded data by default. Up to 32 sets of record data can be uploaded.

The diagram below explains the relationship between TR, NOUD, and TDC more clearly:


2.5 Trggier an uplink by external interrupt

LDS12-NB has an external trigger interrupt function. Users can use the PB15 pin to trigger the upload of data packets.

AT command:

  • AT+INTMOD         // Set the trigger interrupt mode
  • AT+INTMOD=0    // Disable Interrupt
  • AT+INTMOD=1    // Trigger by rising and falling edge
  • AT+INTMOD=2    // Trigger by falling edge
  • AT+INTMOD=3    // Trigger by rising edge

2.6 LiDAR ToF Measurement

2.6.1 Principle of Distance Measurement

The LiDAR probe is based on TOF, namely, Time of Flight principle. To be specific, the product emits modulation wave of near infrared ray on a periodic basis, which will be reflected after contacting object. The product obtains the time of flight by measuring round-trip phase difference and then calculates relative range between the product and the detection object, as shown below.


2.6.2 Distance Measurement Characteristics

With optimization of light path and algorithm, The LiDAR probe has minimized influence from external environment on distance measurement performance. Despite that, the range of distance measurement may still be affected by the environment illumination intensity and the reflectivity of detection object. As shown in below:


① Represents the detection blind zone of The LiDAR probe, 0-10cm, within which the output data is unreliable.

② Represents the operating range of The LiDAR probe detecting black target with 10% reflectivity, 0.1-5m.

③ Represents the operating range of The LiDAR probe detecting white target with 90% reflectivity, 0.1-12m.

Vertical Coordinates: Represents the radius of light spot for The LiDAR probe at different distances. The diameter of light spot depends on the FOV of The LiDAR probe (the term of FOV generally refers to the smaller value between the receiving angle and the transmitting angle), which is calculated as follows:


In the formula above, d is the diameter of light spot; D is detecting range; β is the value of the receiving angle of The LiDAR probe, 3.6°. Correspondence between the diameter of light spot and detecting range is given in Table below.


If the light spot reaches two objects with different distances, as shown in Figure 3, the output distance value will be a value between the actual distance values of the two objects. For a high accuracy requirement in practice, the above situation should be noticed to avoid the measurement error.

2.6.3 Notice of usage

Possible invalid /wrong reading for LiDAR ToF tech:

  • Measure high reflectivity object such as: Mirror, Smooth ceramic tile, static milk surface, will have possible wrong readings.
  • While there is transparent object such as glass, water drop between the measured object and the LiDAR sensor, the reading might be wrong.
  • The LiDAR probe is cover by dirty things; the reading might be wrong. In this case, need to clean the probe.
  • The sensor window is made by Acrylic. Don't touch it with alcohol material. This will destroy the sensor window.

2.6.4 Reflectivity of different objects

1Black foam rubber2.4%
2Black fabric3%
3Black rubber4%
4Coal (different types of coal)4~8%
5Black car paint5%
6Black Jam10%
7Opaque black plastic14%
8Clean rough board20%
9Translucent plastic bottle62%
10Carton cardboard68%
11Clean pine70%
12Opaque white plastic87%
13White Jam90%
14Kodak Standard Whiteboard100%

Unpolished white metal surface

16Glossy light metal surface150%
17stainless steel200%
18Reflector plate, reflective tape>300%

2.7 Set Transmit Interval Time

Feature: Change NB-IoT End Node Transmit Interval.

AT Command: AT+TDC

Command ExampleFunctionResponse
AT+TDC=?Show current transmit Interval

the interval is 30000ms = 30s

AT+TDC=60000Set Transmit Interval

Set transmit interval to 60000ms = 60 seconds

Downlink Command: 0x01

Format: Command Code (0x01) followed by 3 bytes time value.

If the downlink payload=0100003C, it means set the END Node's Transmit Interval to 0x00003C=60(S), while type code is 01.

  • Example 1: Downlink Payload: 0100001E       // Set Transmit Interval (TDC) = 30 seconds

  • Example 2: Downlink Payload: 0100003C      // Set Transmit Interval (TDC) = 60 seconds  


2.8 Clock logging (Since firmware version v1.2.1)

Sometimes when we deploy lots of end nodes in field. We want all sensors sample data at the same time, and upload these data together for analyze. In such case, we can use clock loging feature.

We can use this command to set the start time of data recording and the time interval to meet the requirements of the specific collection time of data.

  • AT Command: AT+CLOCKLOG=a,b,c,d

a: 0: Disable Clock logging.   1: Enable Clock Logging

b: Specify First sampling start second: range (0 ~ 3599, 65535)         // Note: If parameter b is set to 65535, the log period starts after the node accesses the network and sends packets.

c: Specify the sampling interval: range (0 ~ 255 minutes)

d: How many entries should be uplink on every TDC (max 32)




After the node sends the first packet, data is recorded to the memory at intervals of 1 minute. For each TDC uplink, the uplink load will include: battery information + the last 5 memory records (payload + timestamp).


Note: Users need to synchronize the server time before configuring this command. If the server time is not synchronized before this command is configured, the command takes effect only after the node is reset.

  • Downlink ommand: 0x0A

Format: Command Code (0x0A) followed by 5 bytes.

  • Example 1: Downlink Payload: 0A01FFFF0F08             // Set SHT record time: AT+CLOCKLOG=1,65535,15,8
  • Example 1: Downlink Payload: 0A0104B00F08             // Set SHT record time: AT+CLOCKLOG=1,1200,15,8

Note: When entering the downlink payload, there must be no Spaces between bytes.

2.9 Example Query saved historical records

  • AT Command: AT+CDP

This command can be used to search the saved history, recording up to 32 groups of data, each group of historical data contains a maximum of 100 bytes.


2.10 Uplink log query

  • AT Command: AT+GETLOG

This command can be used to query upstream logs of data packets.


2.11 Scheduled domain name resolution

This command is used to set up scheduled domain name resolution.

AT command:

  • AT+DNSTIMER=XX   // Unit: hour

After setting this command, domain name resolution will be performed regularly.

2.12 Set the QoS level

This command is used to set the QoS level of MQTT.

AT command:

  • AT+MQOS=xx   // 0~2

Downlink command: 0x07

Format: Command Code (0x07) followed by 1 byte.

Ex1: Downlink payload: 0x0700   //AT+MQOS=0

Ex2: Downlink payload: 0x0701   //AT+MQOS=1

3. Configure LDS12-NB

3.1 Configure Methods

LDS12-NB supports below configure method:

3.2 AT Commands Set

AT+<CMD>?           : Help on <CMD>

AT+<CMD>                      : Run <CMD>

AT+<CMD>=<value>      : Set the value

AT+<CMD>=?          : Get the value

General Commands       

AT                    : Attention        

AT?                  : Short Help      

ATZ                 : MCU Reset     

AT+TDC          : Application Data Transmission Interval

AT+CFG          : Print all configurations

AT+CFGMOD           : Working mode selection

AT+DEUI                  : Get or set the Device ID

AT+INTMOD            : Set the trigger interrupt mode

AT+5VT           : Set extend the time of 5V power   

AT+PRO          : Choose agreement

AT+RXDL        : Extend the sending and receiving time

AT+DNSCFG   : Get or Set DNS Server

AT+GETSENSORVALUE   : Returns the current sensor measurement

AT+NOUD  : Get or Set the number of data to be uploaded

AT+CDP     : Read or Clear cached data

AT+SHTEMP:   Get or Set alarm of temp

AT+SHHUM:   Get or Set alarm of moisture

AT+SERVADDR :   Server Address

UDP Management

AT+CFM  :    Upload confirmation mode (only valid for UDP)

MQTT Management

AT+CLIENT               : Get or Set MQTT client

AT+UNAME              : Get or Set MQTT Username

AT+PWD                  : Get or Set MQTT password

AT+PUBTOPIC          : Get or Set MQTT publish topic

AT+SUBTOPIC          : Get or Set MQTT subscription topic


AT+FDR              : Factory Data Reset

AT+PWORD        : Serial Access Password

AT+LDATA           : Get the last upload data

AT+CDP               : Read or Clear cached data

4. Battery & Power Consumption

LDS12-NB use ER26500 + SPC1520 battery pack. See below link for detail information about the battery info and how to replace.

Battery Info & Power Consumption Analyze .

5. Firmware update

User can change device firmware to::

  • Update with new features.
  • Fix bugs. 

Firmware and changelog can be downloaded from : Firmware download link

Methods to Update Firmware:

  • (Recommended way) OTA firmware update via BLE: Instruction.

6. FAQ

6.1 How can I access t BC660K-GL AT Commands?

User can access to BC660K-GL directly and send AT Commands.

See BC660K-GL AT Command set

6.2 How to configure the certificate?

an can refer to this description to configure the certificate.

7. Trouble Shooting

7.1 Significant error between the output distant value of LiDAR and actual distance

Cause ①Due to the physical principles of The LiDAR probe, the above phenomenon is likely to occur if the detection object is the material with high reflectivity (such as mirror, smooth floor tile, etc.) or transparent substance. (such as glass and water, etc.)

Troubleshooting: Please avoid use of this product under such circumstance in practice.

Cause ②The IR-pass filters are blocked.

Troubleshooting: please use dry dust-free cloth to gently remove the foreign matter.

8. Order Info

Part Number: LDS12-NB-XX


  • GE: General version ( Exclude SIM card)
  • 1D: with 1NCE* 10 years 500MB SIM card and Pre-configure to DataCake server

1NCE SIM Card NB-IoT network coverage: Austria, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Finland, Germany, Great Britain, Greece, Hungary, Ireland, Italy, Latvia, Malta, Netherlands, Norway, Puerto Rico, Russia, Slovak , Republic, Slovenia, Spain, Sweden, Switzerland, Taiwan, USA, US Virgin Islands

9. ​Packing Info

Package Includes:

  • LDS12-NB NB-IoT LiDAR ToF Distance sensor x 1
  • External antenna x 1

Dimension and weight:

  • Device Size: 13.0 x 5 x 4.5 cm
  • Device Weight: 150g
  • Package Size / pcs : 14.0 x 8x 5 cm
  • Weight / pcs : 180g

10. Support

  • Support is provided Monday to Friday, from 09:00 to 18:00 GMT+8. Due to different timezones we cannot offer live support. However, your questions will be answered as soon as possible in the before-mentioned schedule.
  • Provide as much information as possible regarding your enquiry (product models, accurately describe your problem and steps to replicate it etc) and send a mail to


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