I am in a need to design a circuit using either PS/2 or USB keyboard as Input selector for app.100 inputs. I did googling. But nothing Helped me. Can Any one Help me to design this.
First, you need a microcontroller, for example AT89S52, that can "understand" PS/2 keyboard code ..
There are plenty of entries on this issue here in this forum .. use SEARCH ..
After you establish communication between the microcontroller and the keyboard you can connect 4 (96 inputs) or 5 (120 inputs) PIAs such as 82C55, each with 24 general purpose inputs/outputs and define pins as inputs .. that’s all ..