How quickly can you tell what this is?

It beeps for a couple of seconds at the start and at the end of a blackout.

Go to the head of the class. Over here we have times when there's no power outage for days and then, several times a day. It's annoying when it goes out while I'm receiving visitors on the verandah or taking a break waiting for a process to finish. It's just as annoying to have it come back and not know about it. So I decided to make something to alert me.

The objectives were that power consumption should be low as it has to be on all the time, and that it shouldn't need a battery. At first I installed single LEDs powered by the mains through a capacitor in those places where I spend most of my time away from my desk. But this was not really satisfactory as I had to keep glancing at the LEDs.

Then I came up with the idea for this design. It emits a piercing whistle when the power goes out and when it comes back on. Out of the many simple gadgets I've made for my own use over the years, this is one of the more useful ones.

It's a great idea. I'd like to be able to add a name to the image file I'm saving, tell us, who is Pimpon?

My name's Zotin Khuma. I'm a member of one of the numerous minority races in India, living in one of the most isolated regions of the country.

For use with 120V systems, I suggest raising the value of C1 to at least 0.22uF. This value will also make the circuit respond faster in a 230V system when power returns. I used the 0.1uF only to keep the whole thing as compact as possible.

Due to the wide tolerance of switching thresholds of the schmitt inverter, some samples may need tweaking the timing components values a bit. Mine worked fine with these values from the start.

That's a fine contribution!

There you go, Pimpom. That endorsement is equivalent to a blessing from the Pope around here!

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Yes !

And what a nice useful circuit, Pimpom !

Not exactly. Nobody thinks that Win is infallible, but his endorsement is worth having, even if you aren't supersititious.

Oh come on Bill FFS.

Sloman's endorsement is the kiss of death.

Cursitor Doom is a half-wit, and it does need pointing out from time to time.

Mike Terrell isn't as bad as he tries to make himself look ...

Well yes, but not in this case.

He does have a habit, Bill, of using "How to Win Friends and Influence People" techniques, e.g. gratuitously using their forenames in an attempt to suck up to those from whom he craves approval.

"The sweetest sound to anybody's ears is their own name", isn't that right, Bill?

(Retires left, to take some metformin to keep blood sugar level under control)

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Win isn't any kind of Pope - that would make Cursitor Doom one of his colle ge of cardinals, and Jim Thompson another - and he doesn't have any knd of institutional role that might make his "blessing" more worthwhile than anyb ody else's. The more appropriate analogy would be to compare his endorsemen t with Paul McCartney saying something nice about one of Pimpom tunes (if h e'd written one).

Then again Win isn't a Blumlein or a Baxandall either, though he does come a bit closer to them than some I could name.

I read "How to Win Friends and Influence People" at a fairly early age, and regarded it as fairly superficial, along the the lines of "flattery works if you don't overdo it". Cursitor Doom may be smart enough to try the techn ique, but he clearly isn't smart enough to make it work.

It might be moving your cerebral glucose levels in the wrong direction - th ey clearly weren't all that high when you started composing this post.

"Slowman's endorsement" is an oxymoron.

You noticed! :)

Thanks, I appreciate the compliment. I saw it last night but my ISP went down before I could reply. It was already midnight here and I decided to turn in for the night. Then a first cousin of mine died earlier today and I've just come back after spending several hours at his house.

BTW, Pimpom was the name of my dog who died of cancer quite some time ago.

Moron is close enough!

Btw, speaking of power monitor cicuits, my two UPSes use morse code in the beeps. "ON", "OFF" and "E" while its supplying power to the devices.

Much prefer to see circuits here than politics.

NT

Jamie has trouble with polysyllabic words, and simplifies them to something he can recognise. "Moron" is easy for him, because it's all over his case notes.

Everybody understand Morse code, even Jamie.