It's intended as an educational toy for my 2 year old son. The idea is that he plays with letters and numbers and eventually spelling and maybe even math.
As mentioned above, there is a PS/2 keyboard attached to an ATMega328-P programmed using Arduino. The mcu is connected to an SD card via a DIY socket, and to an audio circuit. The audio makes use of dual pwm(8bit X2 = 16bit) and can support either 8-bit or 16-bit samples at either 8kHz or 16kHz. It runs through a buffer, low-pass filter, and amplifier before heading off to some speakers.
The alphabet and number keys simply speak those letters/numbers. The punctuation and other keys play animal sounds, words or phrases. I am planning to paint all the keys with big, colorful letters or pictures to match the sounds.
Unfortunately, I doubt that would keep a kids attention for very long, so I am currently implementing some simple spelling games and perhaps eventually some simple math games if he finds this toy interesting enough to keep that long. Of course, if I really want it to be entertaining there should be some visual aspect. At the very least some colorful LEDs, but a graphical display of some sort would be great. However, I do not want to go so far as a large monitor type screen because that would not be portable and handleable by a 2 year old. If I had a small graphical LCD screen, that would be ideal, but I don't happen to have one on hand.
Anyway, I'll post logs with all the details, schematics and code. I'm busy these days so I can't write it up all at once.