Please allow me to show you one of the simple robots that I made long ago, when I was "Into" that type of stuff - GRUB BOT 1.2!
This little robot:
1 Has a scrub brush head for a main base
2 Runs entirely on 5 Button-Cell batteries
3 Uses a 3.0 Volt Cell phone motor
4 Cleans clockwise in a 4 1/2 Inch circle
5 Has Wiggle Eyes!
1.0 - Originally ran off of two AAA batteries, and no Wiggle Eyes.
1.1 - Discovered that the AAA's were too heavy, so I replaced them with Button-Cells.
1.2 - Added Wiggle Eyes.
This little guy can clean up Everything! Well, as long as you call "Everything" dust bunnies. However, I'm planning to produce a GRUB BOT - SUCTION EDITION, which will have rotating scrub brushes and a vacuum system - Based on my estimations, it will be able to clean anything from crumbs to broken eggs! (Honestly, this thing will be POWERFUL.) Get back to you on that then!