Skip to main content

Laser Object Detection

Recently, I got a green laser from EBay for only $20.00 (usually these lasers cost $50-$80), to use with my robots. As you can see in the above picture, it's REALLY bright - the range is something like two miles.

The main advantage to a laser is that it puts a very bright light in one precise place. This can be used for things like making two robots align themselves to point towards each other (which I'm thinking of doing for my next project).

Anyway, I found that if I put the laser right on top of a light sensor and pointed it towards the ground (while the light sensor was level), the light sensor would only detect the beam if it reflected off an object a short distance away into the sensor. So I made an attachment for this and put it on Trax, my first successful rover that uses the new treads (using spring-loaded sprockets works great - thanks Brian!):

Below is a video of the robot detecting a wall... notice how the beam moves along the ground until coming across an object. Then it moves up the object as the robot gets closer to the object, until the beam reflects into the light sensor.

Although it was a fun idea, I have to say it's very impractical. The one theoretical advantage it has over the US sensor is that it can detect curved/slanted objects no problem - the reflection of the beam is just as bright no matter how curved or slanted the object is (except of course when the object is a mirror or another highly reflective material). However, usually when the robot comes at a wall from an angle it can't get close enough to the wall for the laser beam to get high enough. It's disadvantages include having a very small range of detection, and being susceptible to ambient light conditions and object textures. It might, however, be useful when combined with the US sensor to provide additional information about potential obstacles.


NOTE: Since lasers (especially green lasers) can harm your eyes if pointed directly at them, you should exercise caution when using them.

Popular posts from this blog


2023 is the 25th Anniversary of the MINDSTORMS brand. For 25 years, MINDSTORMS has educated and inspired a generation of robot builders, both children and adults. Unfortunately, the LEGO Group decided to end the line on December 2022. Many ROBOTMAK3RS have been passionately involved with the development of MINDSTORMS through the MUP and MCP programs. Even with the newest Robot Inventor line, several ROBOTMAK3RS were invited to submit additional bonus models that were included in the official app. Regardless of the retirement of a major LEGO robotics product line, ROBOTMAK3RS continue to MAKE-SHARE-INSPIRE using all LEGO robotics platforms available to us. Here is the official statement from LEGO. Since its launch in September 1998, LEGO MINDSTORMS has been one of the core ‘Build & Code’ experiences in the company’s portfolio, carrying with it significant brand equity and becoming a stand-out experience for the early days of consumer robotics and leading to current Build & Code

Celebrating 25 Years of MINDSTORMS

In celebration of the 25th Anniversary of MINDSTORMS, we take a trip through history. Please also visit ROBOTMAK3RS Community every week as we highlight different projects all through 2023 in celebration of the anniversary. Some of the early history is based on the content shared by  Coder Shah  in our  MINDSTORMS EV3 Community Group . Some of the text and links may have been edited from his original posts for consistency and clarity.  1984 - Kjeld Kirk Kristiansen watched a TV program called "Talking Turtle," where MIT professor Seymour Papert demonstrated how children could control robot "turtles" using LOGO, a programming language he developed. 1988 - The collaboration between MIT and LEGO resulted in LEGO TC Logo in 1988, which allowed students to control LEGO models using computer commands. The video shows Papert demonstrating TC Logo. 1990 - LEGO TC Logo was hampered since the robots you built had to be tethered to a personal computer. LEGO and MIT

Celebrating MINDSTORMS with a Remix Part 1

In honor of the 25th Anniversary of MINDSTORMS, we asked ROBOTMAK3RS to combine a LEGO set of their choice with a MINDSTORMS set. Here is what these five ROBOTMAK3RS came up with.  MINDSTORMS Chess Assistant by Arvind Seshan Overview: When you are new to chess, it can be a challenge to remember which pieces go where. Now, you can use machine learning and LEGO MINDSTORMS Robot Inventor to build a tool to help you learn where all the chess pieces go on the chess board. Sets used: LEGO® Iconic Chess Set (40174) and MINDSTORMS Robot Inventor (51515) Review: I really like how the chess set base can store all the pieces underneath and that the board neatly splits in half for handy storage. The chess pieces themselves are very sturdy and well built. My only criticism is the building of the box itself. It was quite difficult to see what pieces to use and since the entire box is made mostly of thin plates, it took a lot of time and patience. I would have liked the storage area to be sliding dra