If you want to build a button array, follow this diagram. The main idea here is to connect each button to a diode in a row by column fashion, and read all the rows column by column. Rows works as ...

A DIY Robot comprised of two microcontrollers, namely the ESP32 and Arduino Nano; integrated with multiple sensors. An IR Sensor Array [TCRT5000] for Line Following, Ultrasonic Sensor for Obstacle ...