How to Build a Laser Rangefinder? – Step-by-Step Guide with FAQs, Tips, & More

People often ask, how to build a laser rangefinder?

Let’s find out!

How to Build a Laser Rangefinder?

The best way to build a laser range finder is by using a 3D printer. This will allow you to print out all the parts needed to construct it. It’s not cheap but if you already have access to one then this would be a great project to undertake.

Making Rangefinder Using a Laser and a Camera

Kevin Le Brun built a rangefinder by using a laser and a digital camera. He used a laser pointer to project a line onto a wall and he took pictures of this line every 10cm. Then he measured the distance between two points on the wall using these pictures. This method was faster than measuring the wall with a ruler.

A Raspberry Pi camera module is used to capture images of objects. These images are then processed by an algorithm to determine the distance to the object. This information is then sent to a computer screen or printer.

If you want to know tutorials about rangefinder click HERE.

Step 1 – List of Materials

A cheap 6mm 5mw laser. A 220Ω resistor. A 2N2222A transistor or something equivalent. A Raspberry Pi Zero W. A Raspberry Pi Camera v2 or an equivalent. Some jumper wires and a small Breadboard. We used our printer to print a jigger which helped us during the experiment. We also plan to build a complete enclosure using my 3D printer. You can totally do this without.

A laser beam is projected onto a screen. The camera takes pictures of the laser beam as it moves across the screen. The laser beam is moved by a motorized stage.

A Nokia 5110 LCD screen is connected to the Raspberry Pi Zero.

The laser dot is bright because there is a lot of current flowing through the laser. The transistor allows enough current to flow through the laser. The laser dot is bright because there are many electrons flowing through the laser.

Don’t forget to enable the webcam interface using Sudo raspistill via the command line. To test your setup, run the following code: if everything went well you should get an a.jpg file where you will see the background (the default Raspberry Pi wallpaper) and a laser dot.

If you want to know How You Set Up a Halo Xtanium 1000 Rangefinder click HERE.

Step 2 – Detecting the Laser Using OpenCV

Install OpenCV using apt or download the pre-built version for the Pi Zero.

A simple python script to track a laser pointer using a Raspberry Pi Camera Module.

To ensure everything works correctly, at every step we check the captured image to see if the laser is correctly tracked. If you’re using a green laser or if the laser isn’t correctly tracked, you’ll need to adjust the hue-saturation-value threshold of the program accordingly.”

Once the measurement phase is done it is time to actually calculate the parameters. Like the Author We used linear regression, actually, Google Spreadsheet did this job for us.

We re-used those parameters to compute an estimated distance and check it against the actual distance. Now it is time to inject the parameters into the rangefinder program to take measurements.

The code will set up the camera and the GPIOPin 14. Then it will turn on the LCD backlight. After that, every 5 seconds, it will print out the current distance.

The laser diode is enabled. Capture the image in memory. Disable the laser diode. Track the laser using the HSVRange filters. Write the resulting image to the Disk for Debugging purposes. Compute the distance based on the Y coordinate.

Write the distance on the LCD Display. Though the measures are highly accurate and precise enough for my use case there are lots of room for improvement. For example, the Laser Dot is of very poor quality. And the Laser Line is not really centered. Even the Camera is not really well positioned.

We can also increase the resolution by rotating the camera by 90 degrees using the full with and increasing the resolution to the maximum possible. The distance will be more accurate.

As follow-ups, we will need to work on the accuracy improvements I mentioned above and design an enclosure for the rangefinders.

The enclosure should be of precise depth to make sure the walls are parallel. All in all, the current system is enough to help me make my house plans!

If you want to know the difference between v4 and z6 Bushnell rangefinders click HERE.

how to build a laser rangefinder

How to Build a Laser Rangefinder?

Making a Cheap Laser Rangefinder for Arduino

Laser tape measures are used to measure distances. They are very accurate and easy to use. They come in different sizes.

Hardware Components

A simple project that uses an Arduino Nano R3, an OLED display, and a laser tape measure. The Arduino Nano R3 is used as a controller for the LCD screen. The LM2596 is used to power the LCD screen while the laser tape measure is used to measure distances.

If you want to know how to use a rangefinder illuminated scope click HERE.

Hand Tools and Fabrication Machines

Laser tape measures are cheap and accurate tools. You can buy them for about 20$ or even less. The problem is that they need some time to read the distance. This means that you can’t use them in real-time applications.

To solve this problem we used an Arduino board. We attached our laser tape measure to the Arduino board and connected it to the serial port.

Now we can send commands to the Arduino board via serial port and get the distance instantly.

You wrote your own firmware for the laser rangefinder module using an STM32 MCU. Your laser rangefinder module works well, reaching 60Hz measurement speed and measuring up to 6m.

However, you found that the maximum stable distance decreases to about 6 meters.

A laser tape measure is accurate up to 10 mm. You can use this device as a laser tape measure later.


A laser tape measure is a kind of measuring tool. It is used to measure distances. It consists of a laser beam emitter and a photoelectric detector.

The laser beam emitter emits a light beam that travels towards the object being measured.

When the light beam hits an obstacle (such as another object), some of the light energy is reflected back to the emitter.

This reflected light is detected by the photoelectric detector. The distance to the object being measured is determined by how much time elapses before the photoelectric detector detects the reflected light.

If you have any queries feel free to reach out in the comments section.

If you want to know more information about rangefinder click HERE.


  • John Moses

    John is the Editor in Chief here at The Outdoor Stores. His area of expertise ensures that there is no one better to suggest which rifles are most suitable for your hunting experience. He is also available for you to contact him personally to discuss the types of animals you want to hunt and the terrain you will be hunting on. Feel free to read his posts for expert opinion on Rifles, Scopes, Rangefinders, Bonoculars and Monoculars.

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