Planet Arduino

Sudoku is a great way to pass some time, especially on a long flight. However, we don’t think the airlines will let [Sanahm] board with his sudoku-solving robot. The basic machine looks like a 2D plotter made with aluminum extrusion, with the addition of a Raspberry Pi and a camera. The machine can read a sudoku puzzle, solve it, and then fill in the puzzle with a pen. Unlike humans, it should never need to erase its work.

The software uses OpenCV to process the camera data, find the grid, and the cells provided by the puzzle. TensorFlow recognizes the numbers. From there, it is all just math to solve the puzzle. Once solved, the plotter part of the robot takes over and fills in the blanks. After all that, this seems like the easy part.

There’s no video, but the original post has an image of the machine doing its thing. The repository has all the information about the electronics, mechanical construction, and the firmware.

We remember a similar project done with Lego Mindstorms. If you need help getting OpenCV on the Raspberry Pi, we’ve talked about that before, too.

[Hari Waguna] wanted to build a computerized Sudoku game. Ordinarily, that wouldn’t be a big deal. You can buy one, of course, but what fun is that? There’s plenty of apps for phones, but again, not much of a challenge. If you want to preserve your hacker cred, you’d use a CPU board like an Arduino or a Raspberry Pi with an LCD screen, right? But if you want to grow your hacker cred, you’d follow [Hari’s] lead and use 81 seven-segment displays and a membrane keyboard.

Driving that many displays takes some doing (in this case shift registers). [Hari] uses some other tricks, like reading the keyboard using a single pin (and a resistor network). He’s made several videos about the project, including the one below.

The PCB measures eight inches by a little over five inches. Maybe that’s handheld. Practical? Probably not. Cool? Undeniably.

We’ve seen something similar before, although perhaps not as compact. If you really want street cred, you can always try nixie tubes.

Using a rather large custom PCB, Hari Wiguna made a Sudoku board using discreet LED displays and a physical keypad.

Most people, buy a book and play Sudoku with a pencil or perhaps just get an app. Those that are really dedicated buy a standalone game, but this wasn’t good enough for Wiguna, who made his own electronic board not out of a normal LCD screen, but from 27 three-character LED modules to display the game on a glowing grid. Input is done via a keypad, which uses the grid layout to allow for two-button selection of any square.

Though extremely impressive, it doesn’t yet have a puzzle generator. Wiguna would welcome any contributions for this code-wise!

You can find out more about this project on his page, on GitHub, as well as in his detailed YouTube videos below.