I thought about the palm PC but I have one and I don't really use it that often and I don't know if the application I'm creating would be as wide ranging as it would be if I simplified it onto a small pocket calculator. I do have a very inexpensive pocket calculator that I use daily.
I'll try to explain the type of use required:
I looked at the HP20b financial calculator and the look is along the lines of what I want to do however I only need half the functions and hopefully half the size.
I would like to be able to do calculations and once I arrive at a result, plug that result into a category with a date tag. For instance I would like to calculate the difference between two observed quantities and once finding the result log that result into a category selected by the use of a curser that highlights a particular option. When the option is highlighted an enter button is pressed which either brings up another subcategory or arrives at the category into which I want to log the data, depending on the variations within a category.
Step 1 - Press key to select category
Display - Shows three options with middle option highlighted
Step 2 - Press enter to select highlighted category option or left/right arrow key to move curser and highlight desired category.
Display - Next set of sub categories are displayed on screen, one of which is highlighted.
Step 3 - Press enter to select highlighted category or use left/right arrow key to hightlight another category option.
Display - Target sub category is arrived at and selected by pressing enter key.
Step 4 - Calculation is performed to arrive at result and once result is obtained enter key is pressed to insert result into category.
Display - Shows result along side of empty date field and date is typed in using number keys.
Step 5 - Press enter key to finish category entry.