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Lightware GRF-250 Manual

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GRF-250 laser rangefinder
The world's smallest and lightest
250-meter laser rangefinder.
Disclaimer
Information found in this document is used entirely at the reader's own risk and whilst every effort has been made
to ensure its validity, neither LightWare Optoelectronics (Pty) Ltd, its subsidiaries, nor its representatives make any
warranties with respect to the accuracy of the information contained herein.
GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024
Page 1 of 41

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Summary of Contents for Lightware GRF-250

  • Page 1 Information found in this document is used entirely at the reader’s own risk and whilst every effort has been made to ensure its validity, neither LightWare Optoelectronics (Pty) Ltd, its subsidiaries, nor its representatives make any warranties with respect to the accuracy of the information contained herein.
  • Page 2 Thank you for selecting LightWare as your partner in distance sensing technology. LightWare is a pioneer in microLiDAR® distance sensors and laser rangefinders (LRF), drawing upon four decades of expertise in LiDAR technology to develop application-specific products renowned for their accuracy, reliability, and durability.

  • Page 3: Table Of Contents

    Five distance output ............................23 First and last pulse detection ......................... 23 Sleep mode ............................... 23 Serial UART and I2C communication interface .................... 25 GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 3 of 41...
  • Page 4 Cleaning ................................38 13.3 Electrical safety ..............................38 13.4 Service and repairs ............................39 End-of-life safe disposal ..........................40 Document revision history ..........................41 GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 4 of 41...

  • Page 5: Overview

    1M eye safety standards. The GRF-250’s accuracy is not affected by the color or texture of the target or object surface or the laser beam’s angle of incidence. It is virtually immune to background light, wind, and noise, rendering it an ideal sensor for outdoor use.

  • Page 6: Safety

    Always adhere to these product safety precautions and operate the sensor strictly following the guidelines outlined in this product guide. LightWare bears no responsibility or liability for any damage or injury, whether direct or indirect, arising from a failure to comply with these stipulations.

  • Page 7: Labeling

    Figure 2: GRF-250 laser warning label Important note: It is a legal requirement to display the laser warning label on your final product or system. To assist with this, LightWare has included an extra laser warning label in the packaging.

  • Page 8: Key Technical Specifications

    Key technical specifications Table 2: GRF-250 laser rangefinder key technical specifications GRF-250 laser rangefinder key technical specifications Performance 10 to 250 m / 32.8 to 820.2 ft Range (at 50 Hz update rate, 40% albedo, 10 km visibility, 1.4 x 1.4 m target size)

  • Page 9: Optional Accessories

    LightWare website: USB communication cable To configure and test your LRF via LightWare Studio, a USB cable is needed. A USB 2.0 with a data transfer rate of 480 Mbps or more is recommended. Figure 3: USB2.0_C_M/M USB cable for GRF-250 Pixhawk adapter To use your GRF-250 laser rangefinder as an autopilot sensor for above ground level (AGL) or...

  • Page 10: Breakout Board

    An optional breakout board accessory is available to facilitate the integration of the LRF into a host controller such as a Pixhawk, PX4, Raspberry Pi, Arduino, etc. It consists of four reusable adapter boards to conveniently connect the GRF-250 communication cable to other standard cables and host controllers, without requiring soldering.

  • Page 11: Getting Started

    Getting started LightWare Studio is a free application (available for Windows, macOS, and Linux) and the gateway to configure your laser rangefinder and visualize your data. This software empowers you to customize settings, fine-tune sensor parameters, and easily analyze data. It also facilitates firmware upgrades and in-field diagnostics and support.
  • Page 12 Please allow the installation process to complete. LightWare Studio will automatically detect the LRF upon successful connection, displaying the device name in the home screen. The red power LEDs on the back of the LRF will light up.
  • Page 13 Point the sensor at different obstacles to observe instant changes in distance, providing valuable insights into the sensor's live functionality. Figure 9: LightWare Studio distance graph screen showing measurements On this screen, you can control specific device parameters, which are also accessible from the dedicated parameters screen.
  • Page 14 10. Data can be downloaded and saved using the save icon above the data. Figure 11: LightWare Studio distance log screen showing measurements GRF-250 LRF |...

  • Page 15: Parameters, Filters, Settings And Tools

    Parameters, filters, settings and tools Setting the device parameters Your LightWare LRF can be configured via LightWare Studio or from a host controller through the serial or I2C communication interfaces. In the left panel, click on Parameters to open the detailed parameters screen.
  • Page 16 Set your device parameters according to your requirements. Refer to the table below for more information. Table 4: GRF-250 adjustable parameters Parameter Explanation Options Communication Serial UART baud The baud rate used by the serial From 9600 to 921,600 rate UART interface in kbps.

  • Page 17: Filters

    Typically used when monitoring the distance to stationary surfaces, such as when taking level measurements and filling rates. GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 17 of 41...

  • Page 18: Settings And Tools

    Settings and tools Additional application settings are available by clicking on the gears icon in the top menu: Figure 13: LightWare Studio application settings screen You can access the specialized device tools screen by clicking on the wrench icon in the top...

  • Page 19: Installation, Cabling, And Mounting

    Installation, cabling, and mounting Mechanical interface For detailed CAD files, please refer to the LightWare resource center at https://lightwarelidar.com/. Figure 15: GRF-250 mechanical interface Caution: Ensure that adequate ventilation or heat sinking is provided if the LRF is incorporated into a custom enclosure, as heat build-up could occur.

  • Page 20: Communication And Power Cable

    The LRF is supplied with a A08SUR08SUR32W102A communication cable. Spare cables are available from the LightWare online store: https://lightwarelidar.com/. Figure 16: Communication cable pinout Table 5: GRF-250 pinout table Serial / I2C port pin allocations TX / SDA RX / SCL...

  • Page 21: Orientation

    Figure 17: LRF mounting orientations Mounting and alignment instructions The GRF-250 features three mounting feet, facilitating side mounting when integrated with a gimbal system. Take careful note of the following points when mounting the LRF: Caution: When choosing a position, ensure that there is nothing in the path of the •...
  • Page 22 Caution: Ensure adequate ventilation or heat sinking if the LRF is incorporated into a • custom enclosure to prevent heat build-up. Secure the communication cable to prevent it from pulling on the connection port. • GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 22 of 41...

  • Page 23: Advanced Features

    First and last pulse capability enhances performance in challenging environmental conditions like dust, rain, fog, and snow. By discerning both pulses, the GRF-250 can effectively penetrate these elements and accurately report the furthest distance as the actual target. This feature also allows the laser rangefinder to measure the distance to objects through foliage.
  • Page 24 To activate sleep mode, send the value 123 to opcode 98. The unit will respond with the same value and then enter sleep mode. Any subsequent communication with the unit will wake it up to resume normal operation. GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 24 of 41...

  • Page 25: Serial Uart And I2C Communication Interface

    We suggest using LightWare’s pre-built APIs wherever possible, which are available via the LightWare website resource center. If you require more control or do not find a suitable pre- built API, you can use the information below to build a compatible system. The packet- based binary protocol is compatible with higher-level APIs like C, Python, and JavaScript.

  • Page 26: I2C Communication Protocol

    The SDA/SCL pins use 3.3 V logic levels but are also 5 V tolerant. • Requests are made using one of the GRF-250 commands. The complete command list is contained below in this product guide. • When a read request is issued the response will contain the requested data.

  • Page 27: Command Structure For Communication Protocols

    The LRF will not accept and process a packet if the CRC is not correctly formed. Every byte in the packet except for the CRC itself is included in the checksum calculation. GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 27 of 41...

  • Page 28: Checksum Algorithm

    = code << 7 & 0xFFFF; crc ^= code; crc ^= code; code = code << 7; crc ^= code; return crc; return crc; GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 28 of 41...

  • Page 29: Reading Bytes

    Below is the process for reading the raw serial byte stream and identifying packets: Figure 20: Process flow for reading bytes GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 29 of 41...

  • Page 30: Sending Commands

    Below is the process for sending a command request and reading the response: Figure 21: Process flow for sending commands GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 30 of 41...

  • Page 31: Command List

    A 16-byte string indicating product model name. Product Always GRF250 followed by a null terminator. name Use to verify the GRF-250 is connected and operational over the selected interface. Hardware The hardware revision number as a uint32. version /uint32 The currently installed firmware version as 4 bytes.
  • Page 32 (44) stream first and last distance data (45) stream five distances data Distance data in 0.1 m resolution as measured by the GRF-250. Distance This command can be read any time, but if (30) stream is set to 5, this command data will automatically output at the measurement update rate.
  • Page 33 Description exposure /uint8 /uint8 Disabled Enabled Controls the data sampling update rate of the GRF-250, in samples per second or hertz. Update rate RW Reading this command will return the current update rate in Hz. /uint32 /uint32 Writing this command will set the update rate in Hz.
  • Page 34 Writing to this command will set the baud rate. Value Baud rate (bps) 9600 Baud rate 19200 /uint8 /uint8 38400 57600 115200 230400 460800 921600 GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 34 of 41...
  • Page 35 Changing this offset value will change the zero-distance position for the output, 114 Zero offset /int32 /int32 written and read in 0.1 m resolution. GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 35 of 41...

  • Page 36: Firmware Updates

    Firmware updates Occasionally, LightWare will release new firmware for your LRF, to address bug fixes or introduce additional features. All registered customers will receive an email notification when new firmware is released for their LightWare sensor. Caution: LightWare strongly advises that all LightWare sensors are kept up to date with their latest firmware revision.

  • Page 37: Troubleshooting

    • running hot * Coming soon For issues not covered above, refer to the FAQs in the LightWare website resource center or contact LightWare’s dedicated technical support team for assistance with remote testing of your LightWare sensor. GRF-250 LRF |...

  • Page 38: Repair And Maintenance

    13.2 Cleaning If the LightWare LRF lenses collect dust, use a clean, soft cloth or air compressor to remove it. The lenses are coated with an anti-reflective, non-scratch coating. Only appropriate lens cleaning materials should be used to avoid scratching the LRF’s lens or damaging the coating.

  • Page 39: Service And Repairs

    LightWare Studio from the device info screen. Figure 24: LightWare Studio device information screen If the unit needs to be returned to LightWare for repairs, LightWare support will assist you with the Return Merchandise Authorization (RMA) procedure. GRF-250 LRF |...

  • Page 40: End-Of-Life Safe Disposal

    Please do not dispose of LightWare sensors with general household or commercial waste. Figure 25: End-of-life disposal LightWare sensors consist of ABS and other plastics, acrylic, and glass components, which are widely recyclable. The electronic PC board assembly should be disposed of through a reputable electronic waste recycler in your area.

  • Page 41: Document Revision History

    Adding figures in Getting Started section. Added figure for behind glass Rev 1 2024/08/02 installation angle. Updated Communication cable pinout figure. Rev 0 2024/07/29 First edition GRF-250 LRF | Product guide | Revision 3 | 5 Sept 2024 Page 41 of 41...