Hi,
Glad to find this site. I had read lot of postings here to get some help on what I am trying to do, but it is all messed up in my head now.
I have a small digital table alarm clock, the kind with big black-white LCD readings.
The clock runs with a single AA battery. I measured the signal at the buzzer when it beeps. It is badly shaped sine wave with 1v p-p. The alarm is on for entire 1 minute. During this 1 minute, the beep happens once every second. The beep sound frequency is 500Hz or so.
I am trying to get a level high (anyting between 5v-12v will do) when alarm beeps. I mean that I want to see the output of my circuit goes high when the buzzer starts beeping, stays nicely high when it is beeping and goes low when the buzzer stops and 1 couple of seconds pass.
My circuit will have separate power source.
This was my approach.
Since the signal is driving a buzzer, I can connect this signal to a 555 trigger input directly (similar to touch switch project) and get a square wave (rather series of pulses) at the 555's output. I need to make sure this output is high when alarm is not activated.
This output is then connected to another 555 in "missing pulse detector" configuration.
Will this approach work?
If there is any easier approach, may be using only a few discrete components, that would be great. Please guide me.
Glad to find this site. I had read lot of postings here to get some help on what I am trying to do, but it is all messed up in my head now.
I have a small digital table alarm clock, the kind with big black-white LCD readings.
The clock runs with a single AA battery. I measured the signal at the buzzer when it beeps. It is badly shaped sine wave with 1v p-p. The alarm is on for entire 1 minute. During this 1 minute, the beep happens once every second. The beep sound frequency is 500Hz or so.
I am trying to get a level high (anyting between 5v-12v will do) when alarm beeps. I mean that I want to see the output of my circuit goes high when the buzzer starts beeping, stays nicely high when it is beeping and goes low when the buzzer stops and 1 couple of seconds pass.
My circuit will have separate power source.
This was my approach.
Since the signal is driving a buzzer, I can connect this signal to a 555 trigger input directly (similar to touch switch project) and get a square wave (rather series of pulses) at the 555's output. I need to make sure this output is high when alarm is not activated.
This output is then connected to another 555 in "missing pulse detector" configuration.
Will this approach work?
If there is any easier approach, may be using only a few discrete components, that would be great. Please guide me.