Right for my A2 technology project i am making a set of electronic pitch pipes and i was wondering if any of you who may do technology or engineering etc. could help me think of a processing unit for my project.

My project will consist of 6 switches for each string of the guitar or a rotary switch and a screen output and a loudspeaker.

I have worked out the frequencies for each open note in hertz and i am wondering what would allow me to process this.

I was thinking about a PIC then my teacher suggested an Astable so i could work out the resistor and capaciter values needed to make each note using the equation:

f = 1.4/(R1 + 2R2)C

But i was thinking is there any other processing unit any of you know of that i could use?