Table of Contents :

• 1. Introduction
  • 1.1 What is LoRaWAN LiDAR Distance Auto-Clean 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
  • 1.9 Variants
  • 1.10 Mechanical
    • 1.10.1 for LB version
    • 1.10.2 for LS version
• 2. Registering LDS25-LB/LS with a LoRaWAN Network Server
  • 2.1 How does the LDS25-LB/LS work?
  • 2.2 ​Registering with The Things Stack
    • 2.2.1 Add LDS25-LB/LS to The Things Stack
      • 2.2.1.1 Creating an application
      • 2.2.1.2 Adding using the LoRaWAN device repository
      • 2.2.1.3 Uplink Decoder in The Things Stack
      • 2.2.1.4 Activate the device by pressing and holding the ACT button for more than 5 seconds.
  • 2.3 ​Uplink Payload
    • 2.3.1 Device Status, FPort=5
    • 2.3.2 Uplink Payload, FPort=2
    • 2.3.3 Historical measuring distances, FPort=3
    • 2.3.4 Uplink after automatic cleaning, FPort=6 (Since firmware v1.2)
    • 2.3.5 Decode payload in The Things Stack
  • 2.4 ​Show Data in DataCake IoT Server
  • 2.5 Integrating with IoT platforms
    • 2.5.1 Integrate and show data on ThingsEye
      • 2.5.1.1 Configuring The Things Stack
      • 2.5.1.2 Configuring ThingsEye.io
      • 2.5.1.3 Viewing integration details
      • 2.5.1.4 Viewing events
      • 2.5.1.5 Viewing Sensor data on a dashboard
      • 2.5.1.6 Deleting an integration
  • 2.6 Datalog Feature
    • 2.6.1 Ways to get datalog via LoRaWAN
    • 2.6.2 Unix Timestamp
    • 2.6.3 Set Device Time
    • 2.6.4 Poll sensor value
  • 2.7 Frequency Plans
  • 2.8 LiDAR ToF Measurement
    • 2.8.1 Principle of Distance Measurement
    • 2.8.2 Distance Measurement Characteristics
    • 2.8.3 Notes on usage
    • 2.8.4 Reflectivity of different objects
• 3. Configure LDS25-LB/LS
  • 3.1 Configure Methods
  • 3.2 General Commands
  • 3.3 Commands specially designed for LDS25-LB/LS
    • 3.3.1 Set Transmit (uplink) Interval Time
    • 3.3.2 Set Interrupt Mode
    • 3.3.3 Set Power Output Duration
    • 3.3.4 Get or set the automatic cleaning interval
    • 3.3.5 Print data entries by page
  • 3.3.6 Print last few data entries
  • 3.3.7 Clear Flash Record
• 4. Battery & Power Consumption
• 5. OTA Firmware update
• 6. FAQ
  • 6.1 What is the frequency plan for LDS25-LB/LS?
• 7. Troubleshooting
  • 7.1 AT Command input doesn't work
  • 7.2 Significant error between the LiDAR output distance value and the actual distance
• 8. Order Information
• 9. ​Packing Information
• 10. Support

1. Introduction

1.1 What is LoRaWAN LiDAR Distance Auto-Clean Sensor

The Dragino LDS25-LB/LS is a LoRaWAN LiDAR (Time of Flight) Distance Auto-Clean 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 25m)!. 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-LB/LS 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 LoRaWAN IoT Server.

The LoRa wireless technology used in LDS25-LB/LS allows device to send data and reach extremely long ranges at low data-rates. It provides ultra-long range spread spectrum communication and high interference immunity whilst minimizing current consumption.

LDS25-LB/LS supports BLE configure and wireless OTA update which make user easy to use.

LDS25-LB/LS is powered by 8500mAh Li-SOCI2 battery or solar powered + Li-ion battery , it is designed for long term use up to 5 years.

Each LDS25-LB/LS is pre-load with a set of unique keys for LoRaWAN registrations, register these keys to local LoRaWAN server and it will auto connect after power on.

1.2 ​Features

• LoRaWAN 1.0.3 Class A
• Bands: CN470/EU433/KR920/US915/EU868/AS923/AU915/IN865
• 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
• Support Bluetooth v5.1 and LoRaWAN remote configure
• Support wireless OTA update firmware
• AT Commands to change parameters
• Downlink to change configure
• 8500mAh Li/SOCl2 Battery (LDS25-LB)
• Solar panel + 3000mAh Li-ion battery (LDS25-LS)

1.3 Specification

Common DC Characteristics:

• Supply Voltage: Built-in Battery , 2.5v ~ 3.6v
• Operating Temperature: -40 ~ 85°C

Probe Specification:

• Storage temperature: -30℃~80℃
• Operating temperature : -20℃~60℃
• 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

LoRa Spec:

• Frequency Range,  Band 1 (HF): 862 ~ 1020 Mhz
• Max +22 dBm constant RF output vs.
• RX sensitivity: down to -139 dBm.
• Excellent blocking immunity

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

• Sleep Mode: 5uA @ 3.3v
• LoRa Transmit Mode: 125mA @ 20dBm, 82mA @ 14dBm

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 LoRaWAN activate. This mode is used for storage and shipping to save battery life.

Working Mode: In this mode, Sensor will work as LoRaWAN Sensor to Join LoRaWAN 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

1.7 BLE connection

Bluetooth Low Energy (BLE) can be used to configure sensor parameters or view the console output from the sensor. The BLE module will only be activated in the following cases:

• When the button is pressed to send an uplink.
• When the button is pressed to activate the device.
• When the device is powered on or reset.

If there is no active BLE connection within 60 seconds, the sensor will shut down the BLE module to enter low-power mode.

1.8 Pin Definitions

1.9 Variants

LDS25 has two variants:

• LDS25-LB - 8500mAh Li/SOCl2 Battery
• LDS25-LS - Solar panel + 3000mAh Li-ion battery

1.10 Mechanical

1.10.1 for LB version

 Probe Mechanical:

1.10.2 for LS version

2. Registering LDS25-LB/LS with a LoRaWAN Network Server

The LDS25-LB/LS can be registered with any LoRaWAN network server. In this documentation, we use The Things Stack as an example, but similar settings may apply to other LoRaWAN network servers.

2.1 How does the LDS25-LB/LS work?

The LDS25-LB/LS is configured in LoRaWAN Class A mode by default. The device ships with unique registration information that can be used to configure it for OTAA (Over-The-Air Activation).
To connect to a local LoRaWAN network, you must first register the device with the respective LoRaWAN network server using the registration information.

The LDS25-LB/LS's registration information can be found inside the device package.

The registration information includes the following:

• DevEUI
• AppEUI
• AppKey

We recommend using the OTAA activation method because it is more secure than the ABP method. After adding the registration information, press the ACT button to activate the LDS25-LB/LS. It will automatically join the network using OTAA and start sending sensor values. The default uplink interval is 20 minutes.

2.2 ​Registering with The Things Stack

In this section we will guide you through on how to register the LDS25-LB/LS with The Things Stack. If your area has The Things Stack community network coverage, you can use it without setting up your own network. If not, you can set up your own LoRaWAN network coverage by using our LPS8N LoRaWAN gateway. 

The typical end-to-end network setup with LDS25-LB/LS and LPS8v2 is shown below:

2.2.1 Add LDS25-LB/LS to The Things Stack

• Manually

2.2.1.1 Creating an application

Sign up for a free account with The Things Stack Sandbox if you do not have one yet. Then, create an application as shown in the screenshots below.

2.2.1.2 Adding using the LoRaWAN device repository

You can refer to the screenshots below to register your LDS25-LB/LS using The Things Stack's LoRaWAN device repository.

On The Things Stack console:

1. Click Applications.

2. Click the + button and then choose Register end device in an application form the drop-down list.

3. Select your application from the pop-up window.

On the Register end device page:

1. Select Enter end device specifies manually option.

2. Frequency plan: Select the frequency plan that matches your device. E.g.: Europe 863-870 MHz (SF9 for RX2 - recommended).

3. LoRaWAN version: LoRaWAN Specification 1.0.3

4. Regional Parameters version: You can't change it and it will select automatically.

5. JoinEUI: Enter the AppEUI of the device (see the registration information sticker) and Click the Confirm button.

6. DevEUI: Enter the DevEUI of the device (see the registration information sticker).

7. AppKey: Enter the AppKey of the device (see the registration information sticker).

8. End device ID: Enter a name for your end device to uniquely identify it within this application.

9. Click View registered end device option.

10. Click Register end device button.

You will be navigated to the Device overview page.

2.2.1.3 Uplink Decoder in The Things Stack

When the uplink payload arrives in The Things Stack, it is displayed in HEX format, which is not easy to read. You can add the LDS25-LB/LS decoder in The Things Stack for easier readability of each sensor readings.

The uplink decoder can be added to the Payload Formatters of your device in The Things Stack. Refer to the screenshot below.

1. Click Uplink tab.

2. Formatter type: Select Custom Javascript formatter.

3. Formatter code: Copy the uplink payload formatter code from our dragino-end-node-decoder GitHub repository and paste it here.

4. Finally, click on the Save changes button.

2.2.1.4 Activate the device by pressing and holding the ACT button for more than 5 seconds.

Press and hold the button for 5 seconds to activate the LDS25-LB/LS.

The green LED will blink rapidly 5 times, and the device will enter OTAA mode for 3 seconds. Then it will begin the LoRaWAN join procedure. Once successfully joined to the network, the green LED will stay on for 5 seconds.

After a successful join, the device will start uploading messages to The Things Stack, and you will be able to see the messages in the panel.

2.3 ​Uplink Payload

2.3.1 Device Status, FPort=5

You can use the downlink command (0x26 01) to request the LDS25-LB/LS to send its configuration details, including the current configuration status. The LDS25-LB/LS will then uplink a payload via FPort=5 to the network server.

The Payload format is as below:

Example payload in The Things Stack v3:

Sensor Model: For LDS25-LB/LS, this value is 0x3E

Firmware Version: 0x0100, which means v1.0.0

Frequency Band:

0x01: EU868

0x02: US915

0x03: IN865

0x04: AU915

0x05: KZ865

0x06: RU864

0x07: AS923

0x08: AS923-1

0x09: AS923-2

0x0a: AS923-3

0x0b: CN470

0x0c: EU433

0x0d: KR920

0x0e: MA869

Sub-Band:

AU915 and US915:value 0x00 ~ 0x08

CN470: value 0x0B ~ 0x0C

Other Bands: always 0x00

Battery Info:

Calculate the battery voltage as follows:

Battery Voltage (mV) = (High Byte × 256) + Low Byte

0x0C96 = 3222mV

More examples:

Example 1: 0x0B45 = 2885mV

Example 2: 0x0B49 = 2889mV

2.3.2 Uplink Payload, FPort=2

Battery Info:

Check the battery voltage for LDS25-LB/LS.

• Example 1: 0x0C72 = 3186mV

More examples:

• Example 2: 0x0B49 = 2889mV

DS18B20 Temperature sensor:

This is an optional 2 bytes field. You can connect an external DS18B20 sensor to the +3.3V, 1-Wire, and GND pins. This field will then report the temperature.

Example:

• If the payload is 0105H:

  (0105H & FC00H == 0), therefore
  temp = 0105H / 10 = 26.1°C

• If the payload is FF3FH:

  (FF3FH & FC00H != 0), therefore
  temp = (FF3FH - 65536) / 10 = -19.3°C

Distance:

Represents the measured distance value. The default unit is centimeters (cm), and the value range (parsed as a decimal number) is 0 to 2500. In actual use, the measurement may be affected by the signal strength value (Strength).

Example:

• If the data read from the register is 0x0B 0xEA, then the distance between the sensor and the measured object is:

0x0BEA (hex) = 3050 (decimal) / 10 = 305.0 cm

Distance signal strength:

This refers to the signal strength of the distance measurement. The default output value ranges from 0 to 65,535. When the measurement gear is fixed, the farther the target is, the lower the signal strength. Similarly, a target with lower reflectivity will also result in a lower signal strength. When the Strength value is greater than 100 and not equal to 65,535, the measured Distance value is considered reliable.

Example:

• If the payload is 016C(H) = 364 (decimal), then the distance signal strength is 364.

Since 364 > 100 and 364 ≠ 65,535, the measured Distance value is considered reliable.

Customers can use the signal strength value to determine whether the environment needs to be adjusted.

1) When the sensor detects valid data:

2) When the sensor detects invalid data:

3) When the sensor is not connected:

Interrupt Pin & Interrupt Level:

This data field indicates whether the packet was generated by an interrupt. Click here for details on the hardware and software setup.

Note: The Interrupt Pin is a dedicated pin on the screw terminal. See the GPIO_EXTI pin mapping for reference.

Example:

• If byte[0] & 0x01 = 0x00: Normal uplink packet
• If byte[0] & 0x01 = 0x01: Interrupt-generated uplink packet

LiDAR temp:

Represents the internal temperature of the sensor.

Example: 

• If the payload is 1C(H), then ((1C << 24) >> 24) = 26 (decimal), so LiDAR temp = 26 °C
• If the payload is F2(H), then ((F2 << 24) >> 24) = -14 (decimal), so LiDAR temp = -14 °C

Message Type:

2.3.3 Historical measuring distances, FPort=3

LDS25-LB/LS stores sensor values, and you can retrieve these historical values via a downlink command.

The historical payload includes one or multiple entries, and each entry has the same format as the real-time distance measurement payload.

Interrupt flag & Interrupt level:

For example, in the US915 band, the maximum payload size for different data rates (DR) is as follows:

a) DR0: Maximum is 11 bytes, so one data entry is sent.
b) DR1: Maximum is 53 bytes, so the device uploads 4 data entries (total 44 bytes).
c) DR2: The total payload includes 11 data entries.
d) DR3: The total payload includes 22 data entries.

If the LDS25-LB/LS has no data available during the polling time, it will uplink 11 bytes of zero.

Downlink:

0x31 67 05 E4 CC 67 05 EA A8 05

Uplink:

40FF0CEE007E1B6705E50040FF0CB2007B1B6705E62C40FF0CA800811B6705E75840FF0CD0007C1B6705E88440FF0CE400791B6705E9B0

Parsed Value:

[DISTANCE , DISTANCE_SIGNAL_STRENGTH , LIDAR_TEMP , EXTI_STATUS , EXTI_FLAG , TIME]

[331,126,27,Low,False,2024-10-09 02:05:52],

[325,123,27,Low,False,2024-10-09 02:10:52],

[324,129,27,Low,False,2024-10-09 02:15:52],

[328,124,27,Low,False,2024-10-09 02:20:52],

[330,121,27,Low,False,2024-10-09 02:25:52],

[342,122,27,Low,False,2024-10-09 02:30:52],

[338,127,27,Low,False,2024-10-09 02:35:52],

[328,126,27,Low,False,2024-10-09 02:40:52]

History read from serial port:

2.3.4 Uplink after automatic cleaning, FPort=6 (Since firmware v1.2)

The LDS25-LB/LS sends this uplink after the automatic cleaning function is enabled.

Note: This is effective only if the d parameter is set to 1 in the command, AT+REMODUST=a,b,c,1

For example, with the command AT+REMODUST=1,1,5,1, the LDS25-LB/LS will  perform a cleaning cycle every 5 minutes and send an uplink after each cleaning is complete.

The uplink payload is 8 bytes in total.

Example: AT+REMODUST=1,1,5,1

Wiper_workmode

This field displays the current cleaning mode.

0x01: "1" - Wiper cleaning is activated at regular intervals

Wiper_clean_times

This field shows the number of Wiper cleanings, with each round trip counted as 1.

Example 1: 0x01(H) = 1 time

Example 2: 0x03(H) = 3 times

Wiper_clean_interval

This field shows the automatic cleaning interval. (Unit: minutes)

Example 1: 0x00 05(H) = 5 minutes

Example  2: 0x03 84(H) = 900 minutes = 15hours

Wiper_last_clean_time

This field shows the start time of the last automatic cleaning.

Unit: Timestamp

Example: 67B45050(H) = 1739870288(D)

Paste the decimal value into this converter (https://www.epochconverter.com/https://www.epochconverter.com/) to get the human-readable time.

2.3.5 Decode payload in The Things Stack

When using The Things Stack (TTS), you can add a payload formatter to decode the payload.

2.4 ​Show Data in DataCake IoT Server

Step 3: Create an account or log in Datacake.

Step 4: Search the LDS25-LB/LS and add DevEUI.

After added, the sensor data arrive TTN V3, it will also arrive and show in Datacake.

2.5 Integrating with IoT platforms

The LDS25-LB/LS sensor data can be integrated with other IoT platforms for better visualizing and analyzing the data. In this section, we will show you how to integrate sensor data from The Things Stack with some popular IoT platforms.

2.5.1 Integrate and show data on ThingsEye

The Things Stack application supports integration with ThingsEye.io. Once integrated, ThingsEye.io acts as an MQTT client for The Things Stack MQTT broker, allowing it to subscribe to upstream traffic and publish downlink traffic.

2.5.1.1 Configuring The Things Stack

We use The Things Stack Sandbox in this example:

• In The Things Stack Sandbox, go to the Application for the LDS25-LB/LS you added.
• Select MQTT under Integrations in the left menu.
• In the Connection information section, under Connection credentials, The Things Stack displays an auto-generated username. You can use it or provide a new one.
• Click the Generate new API key button to generate a password. You can view it by clicking on the visibility toggle/eye icon. The API key works as the password.

2.5.1.2 Configuring ThingsEye.io

The ThingsEye.io IoT platform is not open for self-registration at the moment. If you are interested in testing the platform, please send your project information to admin@thingseye.io, and we will create an account for you.

• Login to your ThingsEye.io account.
• Under the Integrations center, click Integrations.
• Click the Add integration button (the button with the + symbol).

On the Add integration window, configure the following:

Basic settings:

• Select The Things Stack Community from the Integration type list.
• Enter a suitable name for your integration in the Name text box or keep the default name.
• Ensure the following options are turned on.
  • Enable integration
  • Debug mode
  • Allow create devices or assets
• Click the Next button. you will be navigated to the Uplink data converter tab.

Uplink data converter:

• Click the Create new button if it is not selected by default.
• Enter a suitable name for the uplink data converter in the Name text box or keep the default name.
• Click the JavaScript button.
• Paste the uplink decoder function into the text area (first, delete the default code). The demo uplink decoder function can be found here.
• Click the Next button. You will be navigated to the Downlink data converter tab.

Downlink data converter (this is an optional step):

• Click the Create new button if it is not selected by default.
• Enter a suitable name for the downlink data converter in the Name text box or keep the default name.
• Click the JavaScript button.
• Paste the downlink decoder function into the text area (first, delete the default code). The demo downlink decoder function can be found here.
• Click the Next button. You will be navigated to the Connection tab.

Connection:

• Choose Region from the Host type.
• Enter the cluster of your The Things Stack in the Region textbox. You can find the cluster in the url (e.g., https://eu1.cloud.thethings.network/...).
• Enter the Username and Password of the MQTT integration in the Credentials section. The username and password can be found on the MQTT integration page of your The Things Stack account (see 2.5.1.1 Configuring The Things Stack).
• Click the Check connection button to test the connection. If the connection is successful, you will see the message saying Connected.

Click the Add button.

Your integration has been added to the Integrations list and will be displayed on the Integrations page. Check whether the status is shown as Active. If not, review your configuration settings and correct any errors.

2.5.1.3 Viewing integration details

Click on your integration from the list. The Integration details window will appear with the Details tab selected. The Details tab shows all the settings you have provided for this integration.

If you want to edit the settings you have provided, click on the Toggle edit mode button. Once you have done click on the Apply changes button.

2.5.1.4 Viewing events

The Events tab displays all the uplink messages from the LDS25-LB/LS.

• Select Debug from the Event type dropdown.
• Select the time frame from the time window.

• To view the JSON payload of a message, click on the three dots (...) in the Message column of the desired message.

2.5.1.5 Viewing Sensor data on a dashboard

You can create a dashboard with ThingsEye to visualize the sensor data coming from the LDS25-LB/LS. The following image shows a dashboard created for the LDS25-LB/LS. See Creating a dashboard in ThingsEye documentation for more information.

2.5.1.6 Deleting an integration

If you want to delete an integration, click the Delete integration button on the Integrations page.

2.6 Datalog Feature

Datalog Feature is to ensure IoT Server can get all sampling data from Sensor even if the LoRaWAN network is down. For each sampling, LDS25-LB/LS will store the reading for future retrieving purposes.

2.6.1 Ways to get datalog via LoRaWAN

Set PNACKMD=1, LDS25-LB/LS will wait for ACK for every uplink, when there is no LoRaWAN network, LDS25-LB/LS will mark these records with non-ack messages and store the sensor data, and it will send all messages (10s interval) after the network recovery.

• a) LDS25-LB/LS will do an ACK check for data records sending to make sure every data arrive server.

• b) LDS25-LB/LS will send data in CONFIRMED Mode when PNACKMD=1, but LDS25-LB/LS won't re-transmit the packet if it doesn't get ACK, it will just mark it as a NONE-ACK message. In a future uplink if LDS25-LB/LS gets a ACK, LDS25-LB/LS will consider there is a network connection and resend all NONE-ACK messages. 

2.6.2 Unix Timestamp

LDS25-LB/LS uses Unix Timestamp format based on the following:

You can get the Unix timestamp from the following link:  https://www.epochconverter.com/ :

Below is an example using the Code Beauty - Decimal to Hex converter.

So, we can use AT+TIMESTAMP=1611889405 or downlink 3060137afd00 to set the current time 2021 – Jan -- 29 Friday 03:03:25

2.6.3 Set Device Time

You need to set SYNCMOD=1 to enable time synchronization via MAC command.

Once the LDS25-LB/LS joins a LoRaWAN network, it will send a MAC command (DeviceTimeReq). The server will respond with a DeviceTimeAns command to provide the current time to the LDS25-LB/LS. If the device fails to receive the time from the server, it will use its internal time and wait for the next time request. The request interval can be set using the AT+SYNCTDC command (default: 10 days).

Note: LoRaWAN Network Server must support LoRaWAN v1.0.3 (MAC v1.0.3) or higher to support this MAC command feature.

• Supported: ChirpStack, TTN v3, Loriot
• Not supported: TTN v2 .

If the server does not  support this command, it will discard uplink packets containing the time request. As a result, the user will lose that packet when using TTN v2 with SYNCMOD=1.

2.6.4 Poll sensor value

Users can poll sensor values based on timestamps. Below is the downlink command.

2.7 Frequency Plans

The LDS25-LB/LS uses OTAA mode and below frequency plans by default. Each frequency band use different firmware, user update the firmware to the corresponding band for their country.

http://wiki.dragino.com/xwiki/bin/view/Main/End%20Device%20Frequency%20Band/

2.8 LiDAR ToF Measurement

2.8.1 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.

2.8.2 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:

2.8.3 Notes on usage

Possible invalid or incorrect readings with LiDAR ToF technology:

• Measuring high-reflectivity objects such as mirrors, smooth ceramic tiles, or static milk surfaces may result in incorrect readings.
• If there are transparent objects such as glass or water droplets between the measured object and the LiDAR sensor, the readings may be inaccurate.
• If the LiDAR probe is covered with dirt or debris, the readings may be incorrect. In this case, clean the probe.
• The sensor window is made of acrylic. Do not touch it with alcohol-based substances, as this may damage the window.

2.8.4 Reflectivity of different objects

3. Configure LDS25-LB/LS

3.1 Configure Methods

LDS25-LB/LS supports the following configuration methods:

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

• AT Commands via UART Connection : See UART Connection.

• LoRaWAN Downlinks. Instruction for different platforms: See IoT LoRaWAN Server section.

3.2 General Commands

These general commands are used to configure:

• General system settings, such as the uplink interval.

• LoRaWAN protocol and radio-related command.

They are the same for all Dragino devices that support the DLWS-005 LoRaWAN stack. You can find these commands on the wiki:

http://wiki.dragino.com/xwiki/bin/view/Main/End%20Device%20AT%20Commands%20and%20Downlink%20Command/

3.3 Commands specially designed for LDS25-LB/LS

These commands are only valid for the LDS25-LB/LS, as listed below:

3.3.1 Set Transmit (uplink) Interval Time

3.3.2 Set Interrupt Mode

Feature: Sets the interrupt mode for the GPIO_EXTI pin.

When AT+INTMOD=0 is set, GPIO_EXTI functions as a digital input port.

AT Command: AT+INTMOD

Downlink Command: 0x06

Format: Command code (0x06) followed by 3 bytes.

This sets the interrupt mode of the end node. For example, a value of 0x000003 means the interrupt mode is set to 3 (rising edge trigger). The type code is 0x06.

• Example 1:

Downlink Payload: 06000000
// Turns off interrupt mode

• Example 2:

Downlink Payload: 06000003
// Sets the interrupt mode to rising edge trigger

3.3.3 Set Power Output Duration

Control the output duration of 3v3 (VBAT_OUT pin). Before each sampling, the device will:

1. First, enable the power output to the external sensor.

2. Keep it on for the configured duration, read the sensor value, and construct the uplink payload.

3. Finally, turn off the power output.

AT Command: AT+3V3T

Downlink Command: 0x07
Format: Command Code (0x07) followed by 3 bytes.

The first byte is 01. The second and third bytes are the time to turn on.

• Example 1: Downlink Payload: 07 01 00 00     --->   AT+3V3T=0
• Example 2: Downlink Payload: 07 01 01 F4      --->  AT+3V3T=500
• Example 3: Downlink Payload: 07 01 FF FF      --->  AT+3V3T=65535

3.3.4 Get or set the automatic cleaning interval

Function: This setting allows the device to perform auto-cleaning either once before each uplink packet or at regular intervals. (Unit: minutes)

Note: If you set the device to automatically clean before every uplink, it will reduce the lifespan of the silicone on the wipers used by the sensors. Therefore, it is recommended to configure the wipers to activate once per day. (The factory default is one activation every 1440 minutes)

AT Command: AT+REMODUST

Downlink Command: 0x08 02

Format: Command Code (0x08 02) followed by 5 bytes.

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

3.3.5 Print data entries by page

Feature: Print sector data from the start page to the stop page (maximum: 416 pages).

AT Command: AT+PDTA

Downlink Command:

No downlink commands are available for this feature.

3.3.6 Print last few data entries

Feature: Prints the most recent data entries.

AT Command: AT+PLDTA

Downlink Command:

No downlink commands are available for this feature.

3.3.7 Clear Flash Record

Feature: Clears the flash storage used for the data logging feature.

AT Command: AT+CLRDTA

Downlink Command: 0xA3

• Example: 0xA301        //  Same as AT+CLRDTA

4. Battery & Power Consumption

The LDS25-LB uses an ER26500 + SPC1520 battery pack, while the LDS25-LS uses a 3000 mAh rechargeable battery with a solar panel.
See the link below for detailed information about the battery and replacement instructions.

Battery Info & Power Consumption Analyze .

5. OTA Firmware update

User can change firmware LDS25-LB/LS to:

• Change Frequency band/ region.

• Update with new features.

• Fix bugs. 

Firmware and changelog can be downloaded from : Firmware download link

Methods to Update Firmware:

• (Recommanded way) OTA firmware update via wireless:  http://wiki.dragino.com/xwiki/bin/view/Main/Firmware%20OTA%20Update%20for%20Sensors/

• Update through UART TTL interface: Instruction.

6. FAQ

6.1 What is the frequency plan for LDS25-LB/LS?

The LDS25-LB/LS use the same frequency as other Dragino products. User can see the detail from this link: Introduction

7. Troubleshooting

7.1 AT Command input doesn't work

If you can see the console output but cannot type input to the device, please check whether you are including the ENTER key when sending the command. Some serial tools do not send an ENTER automatically when you press the send button, so you may need to manually add it to your input string.

7.2 Significant error between the LiDAR output distance value and the actual distance

8. Order Information

Part Number: LDS25-LB-XX or LDS25-LS-XX

XX: The default frequency band

• AS923: LoRaWAN AS923 band

• AU915: LoRaWAN AU915 band

• EU433: LoRaWAN EU433 band

• EU868: LoRaWAN EU868 band

• KR920: LoRaWAN KR920 band

• US915: LoRaWAN US915 band

• IN865: LoRaWAN IN865 band

• CN470: LoRaWAN CN470 band

9. ​Packing Information

Package Includes:

• LDS25-LB or LDS25-LS LoRaWAN LiDAR ToF Distance Sensor x 1

Dimension and weight:

• Device Size: cm

• Device Weight: g

• Package Size / pcs : cm

• Weight / pcs : g

10. Support

• Support is available Monday to Friday, from 09:00 to 18:00 (GMT+8). Due to time zone differences, live support is not available. However, your questions will be answered as soon as possible within the stated support hours.

• Please provide as much information as possible regarding your inquiry, such as product models, a detailed description of the issue, and the steps to reproduce it, and send an email to Support@dragino.cc.