Dimebots are a group of autonomous, independent micro-robots that are as small as a dime, making them among the smallest robots in the world.
This is a very simple open source scanning laser rangefinder. It uses triangulation. Its components cost less than $35 (excluding shipping). This lidar is very useful in robotics - for SLAM and navigation tasks.
The circuit board in the project is drawn using Jiali Chuang EDA, and the code uses Arduino IDE, which is very suitable for beginners who are interested in robots.
The software, hardware, and mechanical structure are all open source.