Are there any sensors that can pick up different levels of something? (e.g colour, voltage ect.)
For example if i had 8 squares, and a sensor on the end of my finger.
Could i touch one square and it a tone
Then could i touch a different square with same finger and output a higher tone?
Yes, there are color sensors available. Check sparkfun.com and adafruit.com
Arduino can read a voltage (0 to 5V) directly also if you want to do that.
Also it can work with touchscreen LCDs I believe.
Would there be a way to do it without the sensors?
just the plain drawing of the piano (no colours, or voltage ect.)
An the gloves that just know where they are on the piano if i move them left and right?
and if i want to hit any note with any finger, i can?
just using the glove code and calibration
put touch sensors + colour sensor in the gloves ?
then you know above which sensor you are (colour) and how hard you press.