The magic IC12
The fastest and cheapest way to build a microcomputer which can solve a popular 9 x 9 sudoku is using
the IC12 from sudokuserver.ch. The chip contains the processor, the system RAM and the programms to run the different tasks needed
for data input, solution finding and output.
The minimal wiring for the 8 pin integrated circuit needs only 3 external components (see fig 1): a push button (the keyboard), a LED (the display) and a battery (the power supply). Anybody with rudimentary soldering skills can assemble this simple "computer system" in a few minutes. It's a popular onehour project (schools!) or an easy primer for electronic enthousiasts. A lot of people build it just for fun - or for prooving that this cheap crazy small "brain" with the size of a nail can solve a sudoku problem really 100 times faster than a human beeing. The minimalistic 1-button / 1-LED user interface can't be fast, but allows data entry of any standard 9x9 sudoku problem. A short button press means a zero entry (a free field) - holding down the button and counting the LED flashes lets the user enter a number between 1 and 9.
For most sodoku problems the compact onchip algorithm of the 8 MIPS microcontroller shows up the solution in few seconds, extremely hard-to-solve sudokus need more time.
Enhanced Circuit with Sound
For reading out the solution of a sudoku or using additional onchip programs, it's recommended to use the wiring of fig 2 showing how to enhance the spartanic user interface by a small piezo speaker. With sound support you can focus writing down the numbers while to bee all ears for the acoustic output of the solution. With the additional high efficiency white LED your device can be uses as a flashlight. Along whith the sudoku solver, the IC12 contains some useful additional software applications like stop watch (resolution 1/100s), guitar tuner, reaction tester, el. random generator, chess timer (or egg watch), round counter etc. Check the table IC12 OnChip Application for a list of all available functions. The preferred startup application can be stored in den system configuration. To save power, the internal chip clock will slow down from 8MHz if the processor has nothing to do. One set of AAA batteries will provide enough power to solve hundreds of 9x9 sudokus (magazine level).