Hi Shahzad,

Another alternative to building your own expansion is the Philips PCF8574 I/O expander. It is an I2C part, so requires two I/O pins on your 2051. It gives 8 I/O pins, and you can address up to 8 of these parts for a total of 64 I/O lines. Enough?

Last time I checked, they were 2.27 USD, so not the cheapest way to go.

Dennis