I plan to use a matrix of 20 x 20 capacitive touch pads which would be scanned sequentially. To get a 20 x 20 matrix of on/off data.

Something like the illustration shown below on a 5 x 10 matrix

0010000100

0010000100

001 1 1 1 1 100

0010000100

0010000100

If you observe carefully, I have written a capital "H" in the bit field above.

The idea is to draw inspiration from the slate and provide the user with a writing area where he/she can write anything. Numbers / English Alphabets / Hindi Alphabets / Kanji ( Chinese ) Alphabets etc. What ever the user writes is scaled and displayed on the Nokia LCD. This is the Unique Selling Point of this device. ( To replace expensive touch screens with a cheap cap-touch matrix )

Along with the above, I also plan to have a "Submit" and "Clear" Push buttons to allow the user to "Save" the bit field, or clear the bit field respectively.