This uses an Arduino, a cheap ultrasonic sensor, and a servo to make a map of the environment and display it on an 8 by 8 dot grid module. A full paper with background, documentation, and pictures can be found here.
Deploy the project super easily with PlatformIO. Alternatively, to use the Arduino IDE: open the library manager and download the Servo, Ultrasonic, and MD_MAX72XX libraries, then copy in src/main.cpp.
This was my final project for JHU's EN.560.112 Electromagnetism & Sensors Lab course in Spring 2021.