How to make touch operated tone generation with a microcontroller?

Hello… Im a mechanical engineer & product designer from india.....Im trying to make a project....for that I need TO produce continuous tone at 6 different frequencies (between 17000hz to20000hz) or (between 20000hz to 26000hz) from single sounder/buzzer. And these 6 frequencies should be operated with 6 capacitive touch points. When ever I touch one of these buttons specific frequency should produce….Can anybody please clear my doubts….

1) Is using microcontroller is my best choice? (Presently im using 555 timers in astable mode to produce specific frequency with 6 Toggle switches.

2) Is it possible to produce a continuous tone at specific frequency with line of code using microcontroller? Im working around 20k frequency….Most of the micro controllers working speed is several Megahertz does this produce tone brakes or any other problem?

3) How many pins & bits microcontroller im going to need?

4) What is the smallest & least power consuming microcontroller I can use?

1) probably yes
2) yes. You have a granularity problem with tones at higher frequencies with low processor clock speeds, what impact does a one bit change in the timer register have on frequency is the question you need to ask. Use this calculator for the AVR at http://www.avrcalc.com/ to give you some idea of how the processor speed impacts on exact frequencies. Once the timer is running, they do so independently of code execution, so no glitches will occur in the tone.
3) touch switch interface, power supplies, tone output. An eight bit processor is all you need. There are 32 bit processors with touch controllers built in, but for your application, you don't have a touch screen, they are far more than you appear to need. There are single chip touch controllers like the Freescale’s MPR121QR2.
It is possible to use the ADC or port pin on the micro for touch control as well. Software has to condition the signal in this case.
4) AVR, PIC, Texas Instruments are all in wide use, all would do it, check their spec sheets.
If you are using a piezo sounder, they do not have a particularly flat frequency response. Check that out for your frequencies of interest before buying. The micro is unlikely to be able to drive it directly,
cheers,
Richard

Further to my reply, see the article here for touch sensing with 8 bit CPUs.
http://electronicdesign.com/dev-tools/smart-capacitive-sensing-design-8-bit-mcus
cheers,
Richard

Thanks a lot for your help.... basically im a product designer(http://www.nishanth.me/home.html) i hardly know about electronics...... Can you imagine how much time it will take to make this for a beginner?? Can i find any related tutorials? or any related projects on web? or it is it better to go for a freelancer? How much should i offer for a freelancer?(I really don't know how hard is this thing to make) i wnat to make this within a month....Please suggest me anything help full....