Can't find an old circuit I saw once.

[Jarod_C]

I hate coming to a forum and being that guy that says "I need a schematic, Thanks." but I saw a schematic for a cricket chirp generator a while back and now I can't find one anywhere. I don't remember if it uses an Op Amp, or a 555. I want to stick it under the couch, and set it to go off every five minutes then watch people try to find it. So, with that, "I need a schematic, thanks."

 

[Torben]

I hate coming to a forum and being that guy that says "I need a schematic, Thanks." but I saw a schematic for a cricket chirp generator a while back and now I can't find one anywhere. I don't remember if it uses an Op Amp, or a 555. I want to stick it under the couch, and set it to go off every five minutes then watch people try to find it. So, with that, "I need a schematic, thanks."

Hi Jarod!

If you just want the finished product, there is the **broken link removed**, which looks like the sort of thing you're after.

If you want to build it yourself, I know I just recently saw a thread about this on this board, but for the life of me I can't find it right now. I believe it didn't use a cricket chirp but something of a higher frequency.


Torben

 

[Jarod_C]

That's what I'm looking for. I would like to build a simpler one. I thought I saw one that used a 555, so it wouldn't be random, but it'd still make me laugh. Plus it would be really small that way to. Thanks for the help.

 

[HarveyH42]

Here's a 555 version I found on my HD, no idea where I got it, never built it...

 

[Jarod_C]

Thanks Harvey, and Torben. That was the exact picture I saw. I had it in my favorites, but this "hobby" has turn the favorites, and files into a nightmare lol. So I think I deleted it when I was trimming stuff up. I can't wait to hide this in someones house.

 

[Torben]

Thanks Harvey, and Torben. That was the exact picture I saw. I had it in my favorites, but this "hobby" has turn the favorites, and files into a nightmare lol. So I think I deleted it when I was trimming stuff up. I can't wait to hide this in someones house.

Now I want to build one and see if I can't drive my wife squirrelly.


Torben

 

[mneary]

Is this the beginning of the audio throwie?....

 

[Bob Scott]

I want to stick it under the couch, and set it to go off every five minutes then watch people try to find it. So, with that, "I need a schematic, thanks."

I know, I know!

Just install a weak old 9V battery in a smoke alarm. Hide the smoke alarm unter the couch. They chirp every few minutes to warn of low battery, and the chirp is so fast you can't tell where it is coming from (unless you already know where it is.)

Bonus: You'll know if there is a fire unter the couch/devan/sofa/chesterfield/futon/davenport/chaise-lounge.

Bob

 

[Jarod_C]

Is this the beginning of the audio throwie?....

Well it wasn't going to be until you said that. After thinking about it, I think that's a good idea. Should be about a buck each, even with a battery.

 

[Jarod_C]

I know, I know!

Bonus: You'll know if there is a fire unter the couch/devan/sofa/chesterfield/futon/davenport/chaise-lounge.

Bob

Lol, it's a win win.

 

[john1]

Fire Alarm Low Battery.

Yes.
Bloody thing.
I didnt know it would do that.
And it was such a long interval between chirps, i did not know where it was coming from.

I knew it was something electronic, the chirp had that ultra consistent duration and timbre even though it didn't last long, and as i recall it was only one brief chirp.
Then nothing for many hours.

After a few days i decided it was upstairs in my house, for a while i had thought it was outside, as i could not think of anything it could be. I had noticed it was a little louder with the door open to the hall (where the stairs are).

So i left all the upstairs doors open too, and next time i noticed a chirp,
it was no different than with the upstairs doors closed.
So i reckoned it was coming from something on the landing area upstairs.

But i didnt find anything that looked different or out of place,
and nothing looked to me like it was made to chirp.

Next day i was lucky, it went off as i walked past it.
My head whipped round like it had been whacked by Mohammed Ali, my eyes fixed on the spot where the sound had come from. A pile of odd bits on a shelf, near the window.
Nothing looked out of place, everything looked the same, all quiet no movement.
I stared at this pile of bits and pieces, then i realised that i was almost looking at a fire alarm that had been sitting there for years.

A little glimmer of recollection came to me ... i wonder if that could be it?
Maybe faulty or low battery ... it was low battery.

A vague sense of relief when i realised it was something so mundane.
I had imagined all sorts of weird things that it might be.

John

 

[audioguru]

I have never found a cricket who can make the chirp of a smoke alarm.
I have also never found a smoke alarm that sounds like a cricket.

 

[Roff]

The most insidious feature of the dying-battery smoke alarm is that it almost invariably begins its infrequent chirps in the middle of the night. Just as you go back to sleep, it will chirp again. You then lie awake, waiting for the next one. This, in my experience, results in a 3AM hunt for the offending alarm. It will probably be so high that you have to go get a ladder after you locate it. And a 9V battery, if you have any.
This all happens in the middle of the night because it is mounted in the ceiling, where the battery gets cold at night, lowering the voltage to the critical level.
All this may be the best argument for changing all your smoke alarm batteries once a year. You can save them for less critical applications.

 

[audioguru]

Some people use cheap Chinese carbon-zinc batteries from The Dollar Store in their smoke alarms without noticing the batteries are leaking in their package and are almost dead when "new".
I use Name-Brand alkaline batteries (they have a "best before" date that is 6 years in the future) in my smoke alarms and replace them in 2 or 3 years and they never beep a Low Battery Warning.