Thing-a-Week #7: Rovio Laser Scanner

Due to certain issues, it is currently difficult to add new sensors to the Rovio. One way around the problem is to use the sensors the Rovio comes with in a new way.

Using some 3D printed parts and a 12mm diameter $15 laser line generator from eBay you can make a basic laser scanner. This is based on the laser scanner design from Kenneth Maxon. It uses the 3mm version (Part # 3BT-P8003-00) of the screws that were tested here.

Here is a picture from the Rovio.

This video shows playback of the data recorded into a ROS bag file. The file contains the timestamped image data and commands sent to the robot.

The laser's focus seems less than ideal, and the focus adjustment ring keeps coming loose despite the addition of teflon tape. I have not tried image processing the results yet but I am going to guess that filtering out the line may prove to be difficult. Using an infrared laser and a camera equipped with an IR bandpass filter would probably make image processing signifigantly easier but that would kind of defeat the point of modifying the Rovio. Converting the image data into a 2D laser scan in ROS using OpenCV should be fairly straightforward but will be left as an adventure for another day.

It looks like the concept could work, but practical details may limit its usefulness. If you want to try making your own, the part files, as always, are available at Thingiverse.