Table of Contents:

• 1. Introduction
  • 1.1 What is LDS25-NB NB-IoT LiDAR ToF Distance Sensor
  • 1.2 ​Features
  • 1.3 Specification
  • 1.4 Applications
  • 1.5 Sleep mode and working mode
  • 1.6 Button & LEDs
  • 1.7 BLE connection
  • 1.8 Pin Definitions , Switch & SIM Direction
    • 1.8.1 Jumper JP2
    • 1.8.2 BOOT MODE / SW1
    • 1.8.3 Reset Button
    • 1.8.4 SIM Card Direction
  • 1.9 Mechanical
• 2. Use LDS25-NB to communicate with IoT Server
  • 2.1 Send data to IoT server via NB-IoT network
  • 2.2 ​Payload Types
    • 2.2.1 General Json Format(Type=5)
    • 2.2.2 HEX format Payload(Type=0)
    • 2.2.3 ThingsBoard Payload(Type=3)
    • 2.2.4 ThingSpeak Payload(Type=1)
  • 2.3 Test Uplink and Change Update Interval
  • 2.4 Trggier an uplink by external interrupt
  • 2.5 LiDAR ToF Measurement
    • 2.5.1 Principle of Distance Measurement
    • 2.6.2 Distance Measurement Characteristics
    • 2.6.3 Notice of usage
    • 2.6.4 Reflectivity of different objects
  • 2.7 Clock logging (Since firmware version v1.2.1)
  • 2.8 Example Query saved historical records
  • 2.9 Uplink log query
  • 2.10 Scheduled domain name resolution
  • 2.11 Set the QoS level
  • 2.12 Get or set the automatic cleaning interval
• 3. Configure LDS25-NB
  • 3.1 Configure Methods
  • 3.2  Serial Access Password
  • 3.3 AT Commands Set
• 4. Battery & Power Consumption
• 5. Firmware update
• 6. FAQ
  • 6.1 How can I access t BC660K-GL AT Commands?
  • 6.2 How to configure the certificate?
• 7. Trouble Shooting
  • 7.1 Significant error between the output distant value of LiDAR and actual distance
• 8. Order Info
• 9. ​Packing Info
• 10. Support

1. Introduction

1.1 What is LDS25-NB NB-IoT LiDAR ToF Distance Sensor

The Dragino LDS25-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 (+/- 6cm up to 6m) and as far as 25 meters (+/-1% starting at 6m). The LiDAR probe uses laser induction technology for distance measurement.

It has a unique dust removal brush structure built in, and the radar drives the dust removal brush to complete the optical mirror dust removal operation, and the user can customize the dust removal confguration.

The LDS25-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.

LDS25-NB supports different uplink methods including MQTT, MQTTs, UDP & TCP for different application requirement, and support uplinks to various IoT Servers.

LDS25-NB supports BLE configure and OTA update which make user easy to use.

LDS25-NB is powered by 8500mAh Li-SOCI2 battery, it is designed for long-term use up to several years.

LDS25-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
• Self-contained Auto-clean function
• Measure Distance: 0.1m~25m
• Accuracy :  ±6cm@(0.1m-6m), ±1%@(6m-25m)
• Resolution : 1cm
• FOV : 3°
• Monitor Battery Level
• Multiply Sampling and one uplink
• Uplink via MQTT, MQTTs, TCP, UDP or CoAP
• 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: 2.6v ~ 3.6v
• Operating Temperature: -40 ~ 85°C

Probe Specification:

• Storage temperature：-30°C~80°C
• Operating temperature: -20°C~60°C
• Measure Distance:
  • 0.1m ~ 25m @ 90% Reflectivity
  • 0.1m ~ 12m @ 10% Reflectivity
• Accuracy : ±6cm@(0.1m-6m), ±1%@(6m-25m)
• Distance resolution: 1cm
• Ambient light immunity: 100klux
• Enclosure rating : IP5X
• Light source : VCSEL
• Central wavelength : 850nm
• FOV : 3°
• Material of enclosure : ABS+PC
• Wire length : 120cm

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

Battery:

• 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

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

LDS25-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 LDS25-NB to communicate with IoT Server

2.1 Send data to IoT server via NB-IoT network

The LDS25-NB is equipped with a NB-IoT module, the pre-loaded firmware in LDS25-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 LDS25-NB.

Below shows the network structure:

There are two version: -GE and -1T version of LDS25-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 LDS25-NB send data to IoT server.

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

• Set up sensor to point to IoT Server. See instruction of Configure to Connect Different Servers.  

Below shows result of different server as a glance.

1T Version: This version has 1NCE SIM card pre-installed and configure to send value to ThingsEye. User Just need to select the sensor type in ThingsEyeand Activate LDS25-NB and user will be able to see data in ThingsEye. See here for ThingsEye Config Instruction.

2.2 ​Payload Types

To meet different server requirement, LDS25-NB supports different payload type.

Includes:

• General JSON format payload. (Type=5)

• HEX format Payload. (Type=0)

• ThingSpeak Format. (Type=1)

• ThingsBoard Format. (Type=3)

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":"866207058378443","Model":"LDS25-NB","distance":355,"distance_signal_strength":132,"lidar_temp":26,"battery":3.394,"signal":25,"1":[352,138,26,"2024/11/06 09:29:25"],"2":[338,134,27,"2024/11/06 09:28:25"],"3":[353,133,26,"2024/11/06 09:27:25"],"4":[346,135,26,"2024/11/06 09:26:25"],"5":[346,141,26,"2024/11/06 09:25:25"],"6":[351,140,26,"2024/11/06 09:24:25"],"7":[347,141,26,"2024/11/06 09:23:25"],"8":[355,128,26,"2024/11/06 09:22:25"]}

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:

f8662070583784433f640d3716000000a5017a1d672b284600c600431c672b281d00e700411d672b27e1014100561c672b27a5015e007c1d672b2769015700771d672b272d015b007b1d672b26f1015c007d1d672b26da0165007b1d672b2679

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

Version:

These bytes include the hardware and software version.

Higher byte: Specify Sensor Model: 0x3f for LDS25-NB

Lower byte: Specify the software version: 0x64=100, means firmware version 1.0.0

BAT (Battery Info):

Ex1: 0x0D37 = 3383mV

Distance:

Represents the distance value of the measurement output, the default unit is cm, and the value range parsed as a decimal number is 0-4000. In actual use, when the signal strength value Strength.

Example:

If the data you get from the register is 0x00 0xA5, the distance between the sensor and the measured object is 00A5(H) = 165 (D) = 165cm.

Distance signal strength:

Refers to the signal strength, the default output value will be between 0-65535. When the ranging gear is fixed, the farther the ranging, the lower the signal strength.

In actual use, when the signal strength value Strength≤60, the measured value of Dist is considered unreliable, and the default output is 4500. When the signal strength is greater than 60 and the actual distance is and the actual distance is 45~60m, the output value of Dist is 4500. When the signal strength is greater than 60 and the actual distance is more than 60m, there will be over-period data appearing as 0 or other abnormal values.

Example:

If payload is: 017A(H)=378(D), distance signal strength=378, 378>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.

LiDAR temp:

Characterize the internal temperature value of the sensor.

Example: 

If payload is: 1D(H) <<24>>24=29(D), LiDAR temp=29°C.

If payload is: F2(H) <<24>>24=-14(D), LiDAR temp=-14°C.

Interrupt:

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

Example:

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)

TimeStamp:   

Unit TimeStamp Example: 672b2846(H) = 1730881606(D)

Put the decimal value into this link(https://www.epochconverter.com)) to get the time.

2.2.3 ThingsBoard Payload(Type=3)

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

{
    "topic": "LDS25-NB-PUB",
    "payload": {
        "IMEI": "866207058378443",
        "Model": "LDS25-NB",
        "distance": 339,
        "distance_signal_strength": 138,
        "lidar_temp": 27,
        "battery": 3.394,
        "signal": 19,
        "1": [348, 129, 26, "2024/11/06 09:16:27"],
        "2": [358, 137, 26, "2024/11/06 09:15:27"],
        "3": [345, 132, 26, "2024/11/06 09:14:27"],
        "4": [351, 132, 26, "2024/11/06 09:13:27"],
        "5": [346, 137, 26, "2024/11/06 09:12:27"],
        "6": [347, 133, 26, "2024/11/06 09:11:27"],
        "7": [337, 132, 26, "2024/11/06 09:10:27"],
        "8": [351, 134, 26, "2024/11/06 09:09:27"]
    }
}

2.2.4 ThingSpeak Payload(Type=1)

This payload meets ThingSpeak platform requirement. It includes six fields. Form 1~7 are:

Distance, Distance signal strength, Temperature, Battery, Signal, Interrupt value & Interrupt level value. 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=Signal value&field6=Interrupt value&field7=Interrupt level 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=7200        // Set Update Interval to 7200s

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

2.4 Trggier an uplink by external interrupt

LDS25-NB has an external trigger interrupt function. Users can use the GPIO_EXTI 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

2.5 LiDAR ToF Measurement

2.5.1 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. 

TF02-Pro-W Detection Angle Diagram:

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

2.7 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)

 Note: To disable clock recording, set the following parameters: AT+CLOCKLOG=1,65535,0,0

Example:

AT+CLOCKLOG=1,65535,1,5

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 Command: 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.

2.8 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.

2.9 Uplink log query

• AT Command: AT+GETLOG

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

2.10 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.

2.11 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

2.12 Get or set the automatic cleaning interval

Function: It can be set to auto-clean once before each uplink packet or set to auto-clean at regular intervals. (Unit: minute)

Note:If you set it to automatically clean once per uplink packet, it will shorten the length of time that the silicone on the wipers that the sensors can be used to clean is available, so it is recommended to use wipers that are activated once a day. (The factory default is to activate every 1440min)

AT Command: AT+REMODUST

Downlink Command: 0x08 02

Format: Command Code (0x08 02) followed by 4 bytes.

• Example 1: Downlink Payload: 08 02 01 01 05 A0       --->   AT+REMODUST=1,1,1440
• Example 2: Downlink Payload: 08 02 01 01 02 D0       --->  AT+REMODUST=1,1,720
• Example 3: Downlink Payload: 08 02 02 01 00 00        --->  AT+REMODUST=2,1,0
• Example 4: Downlink Payload: 08 02 02 02 00 00        --->  AT+REMODUST=2,2,0
• Example 5: Downlink Payload: 08 01                            --->  AT+REMODUST

3. Configure LDS25-NB

3.1 Configure Methods

LDS25-NB supports below configure method:

• AT Command via Bluetooth Connection (Recommended): BLE Configure Instruction.

• AT Command via UART Connection : See UART Connection.

3.2  Serial Access Password

After the Bluetooth or UART connection is successful, use the Serial Access Password to enter the AT command window.

The label on the box of the node will print the initial password: AT+PIN=xxxxxx, and directly use the six-digit password to access the AT instruction window.

If you need to change the password, use AT+PWORD=xxxxxx (6 characters), NB nodes only support lowercase letters.

Note: After entering the command, you need to add a line break, and you can also set automatic line breaks in the Bluetooth tool or UART connection tool.

3.3 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        

AT+MODEL                                   : Get module information

AT+DEUI                                       : Get or set the Device ID

AT+SLEEP                                    : Get or set the sleep status

AT+DEBUG                                   : Set more info output

AT+SERVADDR                            : Get or Set the Server address

AT+TDC                                        : Get or set the application data transmission interval in s

AT+APN                                        : Get or set the APN

AT+RXDL                                      : Get or Set the receiving time

AT+GETSENSORVALUE              : Returns the current sensor measurement

AT+CSQTIME                                : Get or Set the time to join the network

AT+DNSTIMER                              : Get or Set the NDS timer

AT+PRO                                         : Get or Set usage agreement (1:COAP,2:UDP,3:MQTT,4:TCP)

AT+3V3T                                        : Get or Set extend the time of 3V3 power

AT+INTMOD                                  : Get or Set the trigger interrupt mode (0:input,1:falling or rising,2:falling,3:rising)

AT+TIMESTAMP                            : Get or Set UNIX timestamp in second

MQTT & TLS Management

AT+CLIENT                                    : Get or Set the MQTT clientID

AT+UNAME                                    : Get or Set the MQTT Username

AT+PWD                                         : Get or Set the MQTT password

AT+PUBTOPIC                               : Get or set MQTT publishing topic

AT+SUBTOPIC                               : Get or set MQTT subscription topic

AT+TLSMOD                                   : Get or Set the TLS mode

AT+MQOS                                       : Set the QoS level of MQTT

Information           

AT+FDR1                                        : Reset parameters to factory default values except for passwords

AT+FDR                                          : Reset Parameters to Factory Default

AT+PWORD                                    : Get or set the System password

AT+LDATA                                      : Get the last upload data

AT+CDP                                         : Read or Clear cached data

AT+CFG                                         : Print all settings

AT+GETLOG                                  : Print serial port logs

AT+LDATA                                      : Get the last upload data

AT+CDP                                          : Read or Clear cached data

ATZ                                                  : Trig a reset of the MCU

AT+DNSCFG                                   : Get or Set DNS Server

AT+REMODUST                              : Get or set the number of dust removal mode

AT+CLOCKLOG                              : Enable or Disable Clock Logging

COAP Configuration Instructions

AT+URI1                                         : Get or set CoAP option 1

AT+URI2                                         : Get or set CoAP option 2

AT+URI3                                         : Get or set CoAP option 3

AT+URI4                                         : Get or set CoAP option 4

4. Battery & Power Consumption

LDS25-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.

• Update through UART TTL interface : 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

8. Order Info

Part Number: LDS25-NB-XX

XX: 

• GE: General version ( Exclude SIM card)

• 1T: with 1NCE * 10 years 500MB SIM card and Pre-configure to ThingsEye server

9. ​Packing Info

Package Includes:

• LDS25-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 Support@dragino.cc.