Need help building a Pulse Width Modulator for a chiming circuit

[trickae]

I'm thinking of making a chiming circuit that varies the frequency of a chime tone based on the input voltage. The input voltage would most likely come from a comparator - comparing the difference between two inputs. The greater the difference - hopefully V2 >> V1 (v1 is set by the user) the more frequent the chiming sound is.

I'm thinking of buying the chime chip that already comes with a preset tone - just the pulse width modualtion is giving me troubles. Would it be designed using a microcontroller ? PIC?

All i can find on the net is designs for motor speed control - however how would i convert that to an audio freqency control.

Can someone point me in the right direction towards making a good start?

thanks in advance

P.S. - i'm new to personal project design - not too great with microcontrollers as well.

 

[audioguru]

Pulse-width-modulation does not change its frequency. It changes its duty-cycle (the width of the pulses) to efficiently change the average DC voltage that is used to dim an incandescent light bulb or to control the speed of a DC motor.

Make a chime with an oscillator that is switched to play two frequencies.
You can use an LM331 voltage to frequency IC if you want.

 

[trickae]

Thanks, for that - how would i use the chip - are the data sheets available on the net?

 

[audioguru]

I get datasheets from www.datasheetarchive.com but recently their hard drive failed and it will take time for them to back it up.
There are many other datasheets sites.

National Semi makes the LM series. Get datasheets and applications notes from their site.

 

[trickae]

thanks for that - i'll google an LM sheet for the v to f.

Btw - would you happen to know kind of two tonal chime chip + miniture audio amplifer i should get?

 

[audioguru]

I don't know any ding-dong chime IC.

 

[trickae]

ahah ok ok i'll check it out at a hobbyist store.