Why bother solving Sudoku puzzles when you can get a robot to do it? That makes sense, of course, if you can build a text-reading, puzzle-solving and answer-writing android like Swedish hacker Hans Andersson's Sudoku Solver, which he built using a Lego Mindstorms kit.
The robot performs a quick scan of the puzzle, sweeping the light sensor across the page to determine which cells are empty. Once it takes account of the blank areas, it looks through all the non-empty cells pixel by pixel, eventually creating a digital representation of the Sudoku page. To determine the digits on each square, it cleans up the scanned image, removes isolated blotches, thins the lines, determines the width, counts the tips and finds their direction.
The swiveling arm that carries the line-by-line scanner also holds the pen, which the Sudoku Solver uses to write down the answer. Yep, it really solves that thing on its own, with handwriting that looks even more legible than mine. Hans also outfitted the machine with four wheels, which doesn't really do anything to facilitate the Sudoku problem-solving. How cool is a robot, after all, if it can't move around the room, right?
Considering that Lego Mindstorms is technically a toy, the things people have been able to do with it is mighty impressive. If that very slow, very limited processor can solve Sudoku puzzles, imagine what a better brain can manage, from solving Calculus problems to summarizing literary classics. Aaaah, high school homework will never be the same when that happens...