Seek mains strobe to give warning flashes [ot]

If the wall outlet only receives power for about 1 sec where does the strobe light get its power from? It needs to be self powered and remain flashing after the initial 1 second power pulse to the outlet, I would assume. I doubt there is anything this specialised on the market and you would need to design/modify something to do the job.

Sorry Ross, I didn't explain it too well.

I meant to say that I needed the strobe to start up and make one or more flashes in the second or so during which the mains power is provided.

I was guessing some strobes may take a few seconds to charge up and so in their case the reponse would be too slow.

Those devices to which you have provided a link are night-lights NOT strobes.

The time that a strobe takes to fire depends on several factors but mainly the size of the capacitor that is discharged by the flash tube.

So you could adapt a small flash unit to do this by reducing the capacitor.

But why not think in terms of an audible device like a buzzer which could be heard straight away?

-- Graham W

PGM-FI page updated, Graphics Tutorial WIMBORNE Wessex Astro Society's Website Dorset UK Info, Meeting Dates, Sites & Maps Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

I doubt you will find anything like this on the market.

Can you tell us a little more about this equipment, and what you are trying to achieve, as there may be an easier way to do what you want!

They only think I can think of is one of the little strobe lights you get from Maplin

But this is a lot bigger than you have asked for. I have one, and when it is switched on, it starts to flash almost immediately (The flash rate is also adjustable)

Is the strobe going to trigger something else, like a camera, or is it to alert someone?

Sparks...

Perhaps you might explain as to how you are intending to use this facility. Maybe it is simply a testing aid to check function?

If this is the case then it might be easier to use a 230V ac buzzer or bell so you could hear it during the 1 sec pulse - eg. Moeller Z-SU230 or Z-GL230 . It is far easier to listen than to stare at a lamp waiting for it to flash. You might blink when it does and miss it....

You would need to mount the buzzer in a plastic box and connect it via a standard plug and cable.

================================ Do you really need a strobe light to do this?

If it's going to be switched on / off in one second any normal light bulb (e.g. a small candle bulb) will give a momentary flash as it is powered rather like a manual head light flasher.

Cic.

--
================================
Testing UBUNTU Linux
Everything working so far
================================

Yes that's right. I'm looking for a strobe which plugs into the mains, "small like a self-contained night light. ... Something like these in size and fitting".

I already have an audio warning. But in my setup the audio can be overheard too easily so it is not always switched on.

I use a 500W floodlight at present but on very bright days it is hard to see. I figure that strobe flashes are more noticeable,

I use a 500W halogen floodlight at present and this works well enough but not brilliantly.

I would much prefer to have a bright fast flash or two from a xenon strobe lamp.

Did you try a Radio Shack one?

I have seen strobes like that in the US that are used with fire alarm systems. They are no larger than the ones in your first two links. I don't know how soon the begin to flash after power is applied.

--
Vic Roberts
http://www.RobertsResearchInc.com
To reply via e-mail: 
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.

This information is provided for educational purposes only. 
It may not be used in any publication or posted on any Web 
site without written permission.

The first thing anyone used to build when they started electronics used to be a neon flasher.

You need a 400v rectifier diode (IN4007?)rectifier, a capacitor and a resistor and a neon.

Put the rectifier and the resistor in series with the capacitor ( 100v or greater electrolytic +ve to the bar on the rectifier diode), and put the neon across the capacitor as well.

Then connect the whole lot across the mains. Flash period is not far off resistor in megohms x capacitor in uF..

Modifying a neon equipped socket should be relatively trivial.

The Natural Philosopher wrote in news: snipped-for-privacy@proxy02.news.clara.net:

The first thing anyone used to do when answering posts is to read them first. Did you really think a guy who found a 500 watt halogen inadequate was going to be satisfied with a flashing neon lamp??

Granted, the principle IS the same. Thing is, if you want a fast charge to get a xenon lamp flashing within a small fraction of a second with similar repeat interval, you'll need a fairly low resistance to get current into your capacitor fast. That could mean a loss of 10 watts in that resistor, so fitting that into a tiny enclosure safely is a no-no. You either need a bigger unit with good ventillation, OR a small sealed unit that won't start or run at high speed and high energy, you're going to have to compromise at some point.

One possibility is to use a high speed AND high power for fast response, but if you do this in a small container that uses a single second's worth of power supply to get several fast hard flashes done in that second, you'll need to put a timer in there to force it to shut down after that secone even if power is still applied, and you'll want to back that up with a thermal cutout too for safety.

The correct answer to the original post is no.

"Homer J Simpson" wrote in news:2DZah.247$YV4.96@edtnps89:

The post I answered wasn't even a question.

If you mean the real original, then saying no is pointless, the guy already knows you can't easily get a self-contained plugin strobe, or he wouldn't be asking. So he has to make it if he wants one, or adapt something.

Vellemann made a kit you could buy from Maplin, it used around ten watts, started fast, and if you watched the heat dissipation, it could be adapted to something like this. So could one of those tiny £12 widgets used for small DJ setups. You might have to mount it on a shelf or bracket but that's just DIY. So the answer isn't "no".

But you'd have to add some sort of latch to extend the on time from one second.

"Homer J Simpson" wrote in news:9a_ah.363$YV4.152@edtnps89:

He only wants one second's worth. He'll probably get it too, a capacitor that takes the first quarter of a second reaching a charge capable of running the strobe might keep it flashing for a quarter second after the power turns off. If timing to catch the eye is all that matters, this is ok. That Vellemann kit, and probably the DJ type cheap strobes, start very quickly after power is applied, they're meant to be capable of flashing in tens-of-Hz rates. If you set the rate lower, it should run cooler, and still be fast enough to do tens of flashes in the second during power on. The only problem is convenience.

I think the best answer is the cheap DJ types, they're small, safe, legally rated as safe, and they plug in to a standard plug. They fall short of the single plugin lump the OP wanted, but such is life.. On the upside, he gets more choice in position and orientation, and flash speed, than he is likely to get any other way.

Actually, you'd need a second capacitor in the low volt supply in the unit to power the oscillator and trigger circuit to be sure of using the last useful charge in the main cap after power goes, but that's not important unless you're modifying the beacon strobe type.

I think the fast DJ strobe type is a better idea if it's only running for one second, far more eye catching in bright conditions because of the high repeat rate.

not going to compare too good to 500w of halogen.

No, there are many options. If the alarm is only triggered rarely, one might even consider a 110v halogen lamp inside a fixture with protective shield. Its as simple and cheap as it gets, very powerful and fast starting. But you only get 1 flash.

NT

snipped-for-privacy@care2.com wrote in news: snipped-for-privacy@h54g2000cwb.googlegroups.com:

I'm familiar with 500 W halogens at close range, and distant, and the flashing of a strobe is a better contest than you'd think. Fast flashes really catch the attention, as makers of bike lights know. How do you compete with a 60W brake light on each side of a car when all you have is a few LED's powered by a couple of AA batteries? Make them flash, fast. It works, beleive me.

In this case, the light isn't even likely to be competing for the same bandwidth, exactly, even in bright sunlight a strobe will flash with short wavelengths at intensities great enough to be seen.

The OP didn't say whether the thing can be directional or must be widely dispersed. If directional is ok, it could be fronted by a 6" square fresnel lens (often cheap on eBay and from surplus places). You'd still see it from a wide dispersion if you are looking right at it, but even if you are not, it would catch your eye totally if you were stationed in its main field. If it can be directed, much less power needs to be handled.

One idea that might work is a widely dispersed diode laser beam, with a divergence of at least 12°. You can use LED's for this too, but laser diodes are vastly more efficient, and at wide angles like that, are totally safe, and monochomatic light is another good method of competing against powerful broadband light. This can make a very tiny unit, it can also be made to flash. The main weakness is that it's only good if you want it to be highly directional.