1. Introduction

After stumbling across the 2024 Business Card Contest, I thought a little robot that avoids obstacles would be a nice entry. It is no problem to keep the length and width of a business card, the height of 1 to 2 mm is of course impossible for a robot to keep, but with a height of 10 to 20 mm, one can work well. The main body of the robot is a PCB that features a microcontroller, a motor driver, and a LiPo battery charger. I chose the ATMEGA32U4 because it does not require a USB to serial chip. The time of flight sensor VL53L1X alternatively VL53L0X (breakout board) is used as the “eye” or “head” of the robot.

Schematic of the business card robot

N20 geared motors, wheels, and VL53L1X breakout board. The wheels are normally intended for small RC airplanes. The tires are a bit squishy and have a lot of grip, perfect for a small robot

2. Design

Top view of the PCB (90 x 50 mm)

Bottom view of the PCB

3D drawing of the motor mount and the ball caster