I'm running the PS2KeyboardExt2 (http://arduino.cc/playground/Main/PS2KeyboardExt2) and I've changed the line to handle the enter key to actually start a new line. But my problem is I want to enter say 2.2 and enter and it will convert those three characters into a floating point value so I can do (2.2)/2 = 1.1 (for the sake of simplicity).
does anyone know how I can accomplish this?
The answer will depend on what other kinds of input you want to handle.
You need to determine a way to store numbers as they are entered or process the strings afterward. If you are thinking along the lines of taking a line of input like your example: "2.2/2" and then showing a result of "1.1", there isn't a simple method for that. Not impossible, but not 1-2 lines of magic code either.
When dealing with numbers, it is helpful to remember that powers of 10 move an integer to different orders.
Example:
2 * 1.0 = 2.0
2 * 0.1 = 0.2
2.0 + 0.2 = 2.2
You'll need to flush out your idea and give more details on what you are trying to accept as input to get more detailed help.
Try looking for the (avr) C library functions atoi() and atof(). These might do what you want. I don't know if they can be used directly from a sketch, you might have to include the code yourself.
What we're trying to do is build an attractive electromagnetic levitation device. we're using a hall effect sensor and a boost converter circuit so that the inductor acts as the electromagnet and the hall effect sensor provides feedback to keep the magnet in the air. The user will enter the distance they want the magnet to levitate, from the inductor, (say 2.2cm). That number is going to be fed into our equation to get the magnet to levitate at 2.2 cm. The 2.2/2 was just a proof of concept that I can convert the characters to a float point value and do some math with that number. The size of the values will always be 2 sig figs if that helps the max will always be under 10 but greater than 1.
Why don't you just use millimeters instead of cm? Then all the numbers are integers. The
atio() function is part of the c library and callable from a sketch. Documentation for it
is here: avr-libc: <stdlib.h>: General utilities