The Laser Range Finder (LRF) module is a low-cost instrument that uses laser light to measure the distance to a targeted object up to 8 feet away.

The LRF incorporates a multicore Parallax Propeller microcontroller, OmniVision OVM7690 640×480 CMOS CameraCube, and Arima 635nm APC Laser Diode. Distance to a targeted object is calculated by optical triangulation using trigonometry between the centroid of laser light, camera, and object. Applications include distance or liquid level measurements, object detection and/or avoidance, and item counting.

Parallax, Inc. was the exclusive manufacturer of the LRF. The module has been discontinued as of September 17, 2018.

This design is distributed under a Creative Commons Attribution 3.0 United States license.

Module Highlights:

• Optimal measurement range of 6 inches to 4 feet (48 inches)
• Maximum object detection distance of ~8 feet (100 inches)
• Accuracy error of less than 5% (average error of 3%)
• Range finding sample rate of 5 Hz
• Single row, 4-pin, 0.1” header for easy connection to a host system
• Asynchronous serial interface with automatic baud rate detection from 300 to 115,200

Documentation (from Parallax):

• Technical Manual
• Schematic
• Bill-of-Materials
• PCB Layout
• Tool: LRF Image Viewer (Windows XP and later)

Additional Resources:

• Source Code: Parallax Propeller (GitHub)
• Assembly Drawing
• Test Procedure
• Slides: Development Diary: The Parallax Laser Range Finder
• Slides: Laser Range Finding and Game Boy Printing
• Article: Designing a Low-Cost Laser Range Finder – Part 1 (SERVO Magazine, October 2011)
• Article: Designing a Low-Cost Laser Range Finder – Part 2 (SERVO Magazine, November 2011)

Example Projects:

• Arduino
• BASIC Stamp 2 with connection diagram
• Parallax Propeller
• Freescale’s FSLBOT (CodeWarrior for ColdFire v7.2)
• LRF + Nintendo Game Boy Printer with schematic, assembly drawing, PCB layout, and pictures

Videos:

• Multiple LRF Demonstrations (YouTube)
• Firmware Upgrade Instructions by Parallax (YouTube)
• Freescale’s FSLBOT (YouTube)
• LRF + Nintendo Game Boy Printer (YouTube)
• Object Sensing Robot by Roy Eltham (YouTube)
• Hack A Week episode #13 by Dino Segovis