How to convert the voltage into pulses using 89c51 micro?

[chanduchi]

volume control by 89c51 chinese

Hi

How to convert the voltage into pulses (frequency) using 89c51 micro controller?

Aim using AD571 ADC and converting analog voltage in to digital and feeding to microcontroller.

For microcontroller I connected a Buzzer. Depending on input voltage its volume should control. Amplitude is constant but intensity should be change.

How to solve this problem.

Thanks

Regards
chandu

 

[sunish]

volume control depending on input voltage

hai
i assume that the buzzer is a part of the system
if you want change the volume,you have to connect a DAC
ie.digital to analoge convertor to the microcontroller
and the o/p of dac should be given to the buzzer.


hope this will solve the problem


sun

 

[VVV]

Re: volume control

Build a fixed-frequency PWM, whose duty-cycle changes depending on the input voltage. That will change the volume, although there may be a change in the sound, too.
What kind of buzzer are you using?

 

[hr_rezaee]

volume control

hi
use buzzer with oscillator and do what "VVV" said.
regards

 

[chanduchi]

Re: volume control

Thanks for the reply

Here I am comparing the external signal with set point value. Set point value is variable. It well changes to user to user. According to the set point value I want generate the PULSES and give to any musical IC, which generates the sound.

My problem is how to generate the pulses according to input signal.

Regards
chandu

 

[hr_rezaee]

volume control

Hi
do you mean:
you want generate pulses according to input voltage.
you input voltage is limited in a range and therefor your output frequency is limited in a range.
regards

 

[chanduchi]

Re: volume control

Hi

My doubt is how to generate the variable frequency with constant amplitude using 89C51.

The variable frequency is depends on analog input voltage.

So aim planning to take digital value corresponding to the analog input voltage and place the digital value in the TIMER register. If the digital value changes corresponding frequency also Changes. This is my plan. How to implement this one.

Thank you,

Regards

chandu

 

[hr_rezaee]

volume control

Hi
your plan is good.
set timer value proportional with input value and maximum of input value and max frequency.
regards

 

[xischaune]

Re: volume control

Hi...

You can use the ADC input from each user to load the timer and then use the timer to generate PWM...

OR

You can assign each user analog input an ADC range... User1=0000-0011 User2= 0100-0111 etc. Then directly assign these ranges to play a musical insturement or buzzer at different sounds...

Hope this helps...

 

[tom_hanks]

Re: volume control

try this chip...

**broken link removed**