Simple but robust buzzer

[stud9920]

Hello,

I'm looking for a very simple robust single supply system that will
trigger a 3kHz oscillator/piezo-buzzer on and off faster when a high
voltage is applied, slower when a low voltage is applied; iow
"bebebebebebeep" when Vin=5V, "beep....beep...beep" when Vin=0V.

My first approach was to integrate Vin, and to reset it when it
reached a certain value, but this doesn't work for a number of reasons
(the first being that it is impossible to bias the integrator stably
wrt drift and other phenomenons).

I almost forgot : it must be pure analog, and easy to debug with third
world like equipment.

 

[John Fields]

Hello,

I'm looking for a very simple robust single supply system that will
trigger a 3kHz oscillator/piezo-buzzer on and off faster when a high
voltage is applied, slower when a low voltage is applied; iow
"bebebebebebeep" when Vin=5V, "beep....beep...beep" when Vin=0V.

My first approach was to integrate Vin, and to reset it when it
reached a certain value, but this doesn't work for a number of reasons
(the first being that it is impossible to bias the integrator stably
wrt drift and other phenomenons).

I almost forgot : it must be pure analog, and easy to debug with third
world like equipment.

 

[Spehro Pefhany]

Hello,

I'm looking for a very simple robust single supply system that will
trigger a 3kHz oscillator/piezo-buzzer on and off faster when a high
voltage is applied, slower when a low voltage is applied; iow
"bebebebebebeep" when Vin=5V, "beep....beep...beep" when Vin=0V.

My first approach was to integrate Vin, and to reset it when it
reached a certain value, but this doesn't work for a number of reasons
(the first being that it is impossible to bias the integrator stably
wrt drift and other phenomenons).

I almost forgot : it must be pure analog, and easy to debug with third
world like equipment.

Use a low-frequency VCO to gate the 3kHz oscillator on and off. Or use
a microcontroller (eg. 8-pin with ADC) for low parts count.

Best regards,
Spehro Pefhany

 

[Spehro Pefhany]

Use a low-frequency VCO to gate the 3kHz oscillator on and off. Or use
a microcontroller (eg. 8-pin with ADC) for low parts count.

P.S. This can be done for a total BOM of << $1. (100k)

Best regards,
Spehro Pefhany