my ups beeps every 10 seconds when its runnin from battery. which is very annoyin. it then beeps every second once the battery starts to go low and its about to shut down. what i need is some sort of circuit that will sound a buzzer when it beeps every second, and for it to do nothing when it beeps every 10 seconds. any have a schematic or any idea how i can do this?

 

You could get a pic chip, and write a little program to monitor an input line.
If the delay between the line going high again is more than a second, then sound the buzzer, otherwise do nothing.

Im just up the road from you (sunderland - small world isnt it!!!!)

I may be able to knock something up for you if you are interested, still learning pic's - but should be able to do this. If you can interface the beep output to a ttl input then I could supply the pic chip programmed to do it (you would need to hook up the pic to the beeper, and wire up a buzzer, and make sure its safe, as lots of mains in a ups.....)

 

yup. small world

i was looking for something more simpler that doesnt involve PICs. basically just something what will sound a buzzer if the inut goes high with less than a 5sec would be enough

all its to do is warn me when the batteries are going low. since i get a few hours, i dont want it beeping every 10 seconds, but its the same beeper what goes every second when its going low. i have an LED on instead ATM, but its not very practicle when it is going to switch off

 

You can try using a Resistor+diode charging a capacitor, with a discharging resistor across the cap. If the discharging rate is faster than the one second per 10 second interval charging rate, the capacitor will never charges up.

However the capacitor will charge up when the signal is one second per two second interval.

Just connect the capacitor to the gate of a MOSFET which drive a buzzer and you are done.

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L.Chung