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deblen

Strobe Lights

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Hi,

Just wondering if one was to have Curtain Strobe lights in a display.

Does each one have its own Channel, or have in groups.

Any help appreciated.

Deblen

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Hi Deblen,

That all depends on you and the number of channels you want to dedicate to this aspect of your show. So, put as many strobes on one string as you want, but keeping the amount of current this channel can handle in mind. Or put a number of strobes on their own channel as you want, and have available.

Though if you watch other peoples videos. You will notice that usually it is a group of strobes popping, not just one or two.

Max

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I never really find myself in a time when I want different groups of strobes on at different times. I really just use them as a big WOW affect at certain times during the show. Because of that, I use one channel. I have about 50 (I think) on one channel, and they look great when all on at once.

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I thought like that until very recently Greg. Now I'm thinking I'm going to sweep the strobes a few times during the show for 2009. I don't know why, but I've been having one of those "visions" and I think it will look very, very cool. :D

Last year I had 48 strobes on one channel in our mega-tree and it looked awesome when they were all on. For this year, I'm hoping to double that and then have them in groups of 20 or 25 for the sweep.

-Jeff

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I'm looking to add strobes so i'm trying to learn about them. So if i may ask, a dumb question possibly. Do they fire off at differing times or all at once if on the same channel?

Thx, Joe

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The easy answer is yes, they flash at different times.

The real answer is we noticed that for the first couple of seconds some of the lights do seem to flash in unison. Then they work further and further out of sync over the next couple of seconds so it really looks random. You barely notice them flashing in sync but since it was our show, we did notice it. :D

-Jeff

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For my 2009 display I am going to be using about 250 strobes, That will randomly flash when activated by the LOR. (IF, I can Find a power supply to power them all)
(If I can find a big Power supply, my 2009 or 2010 display will have about 1,000 strobes)


They will flash randomly,
Or they may start at the same time but over time will get more and more out of sync with each-other.


It is posable to modify them to flash with a Master Strobe. (IE in sync all at once).
And it could be done without OptoIsolators and transformers
All that would be needed is like one TRIAC and some wire (Rated for 300+Volts)

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Wow, 1000 strobes, I'm sure it will look amazing but are you worried about a plane landing on your house?

If you buy the stobes from different manufactures or vary the resistors in a few of them you should have a nice random pattern.

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I hope it will look amazing, I have modified about 30 and plan on doing them all.
Am trying for a random pattern.

How to mount, hang, and get power to them all (with a very small budget of $150).


IF I can solve the power problems, I could do around 3000+. (Got to love recalls :D)

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I am not worried about a plane crashing into my house.
What I am worried about is epilepsy, that is the biggest thing.



Hey, I think I solved my power problem at a cost of 13 cents per strobe.

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Out of curiosity, what strobes to you use that you need to worry about a power supply? All the strobes I have seen, both for our applications and theatrical, all use standard voltage.

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They are strobes from Advance-auto,
Found them being trashed, I asked him he said due to defects.

They are 7 volts at 370 mA each (shuld be 12 volts. wont work on 6 volts or 9 volts)
The power resetor is the worng wattage (fixed it by increasing the charge time)
I think they are nock-offs, anyways I got 300 of them.

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Wrong "wattage"? Surely changing the wattage will not have an effect on the working voltage. So what value was it? And to what wattage did you change it to? Inquiring minds would like to know.

Max

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Max-Paul wrote:

Wrong "wattage"? Surely changing the wattage will not have an effect on the working voltage. So what value was it? And to what wattage did you change it to? Inquiring minds would like to know.

Max


Yes, the wattage does not change the working voltage. The resistor was over heating and blowing.
It was a 20-ohm 1-watt resistor
7vdc at 350mA = 2.4Watts (So it needs a 3 watt resistor at 20-ohms)
So I added a 16-ohm 5-watt resistor in series with the original thus dividing the power dissipation between them.


What I am thinking will work for fixing the voltage: is to use a 7.5Volt Zener Diode to clamp the Voltage across the strobe, then string about 12 strobes in series and use a 25 watt light bulb as a current limiter to drop the extra voltage.

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Ok, still a little lost about what you are trying to do. I under stand what you have done so far. got a 20 ohm resistor at 1 watt and a 16 ohm 5 watt in series. Ok and you say that the math says you need a 2.4 watt resistor. The problem I see is that you are still dropping more than half of the wattage across the original resistor. And off of the top of my head I would say about 1.5 watts, so it might take a little longer for it to burn up, but it will still burn up if it is left on to long at a give time.

So, what voltage was the test conducted at with the 16 ohm resistor added? Trying to see what the actual working voltage of the strobe is. What are you going to use for a power supply when you have 12 of them strung in series. True a light bulb is a handy high wattage resistor. But with the on and off action, esp with the light bulb outside in the cold. I would think that this will become your weakest link in your display. Pop the filiment due to thermo stress and your whole strobe display will go into the bucket. Spend a few bucks more and get a true power resistor. Then you do not have to worry about one more thing to fail. Elminate as many varibles that can fail. And any filiment type light bulb is a huge failure point.

Would like to hear your plans for this string of 12 strobes.

Max

BTW I see one flaw in your math. If I understand you correctly. The 7 vdc is applied across both the LED / circuit and the 20 ohm resistor. What you have to do, is actually messure the voltage that is being dropped across the resistor. Then multiply this volage by the current, and in this case .384 Amps (I think that was the value you gave). This will then dictate the wattage the resistor has to be able to disapate. 2.4 watts is the total power. I am going to suspect that you will find about 4 volts across this 20 ohm resistor if you P.S. is 7 volts as advertised.

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Ok, because of the new resistor it lowers the amps
7.5volts at 208mA that would be about 0.87watt on the 20-ohm and 0.7watts on the 16-ohm resistor.

I was thinking of rectifying 120Vac and use a capacitor to give me a Large 170Vdc power supply. I may just brake down and buy a real power resistor.
Then string like 20 strobe in series.

They are 7.0 volts dc
The minimum fireing voltage is 6.48 volts dc (tested)
The max is about 8.25 volts dc without exciding the capacitor's voltage rating of 330V (tested)




Attached files 172145=9856-Strobes copy.jpg

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H,

Thanks for all the replies, now you have me wondering about the voltage.

Strobes are had to find in Australia. (240 volt). If I purchase them from the US (110 volt),

To run them I would need to get a 240 to 110 volt convertor, then use this to power them, or do they need to be reduced again to a lowerr voltage.

I think I will put some on the same channel, others on a defferent channel.

Might end up using 6 or 7 LOR Channels on the strobe effect.

Any tips on the voltage setup you are using. Can I just step down to a lower voltage or does it have to be 110 volt.

By the diagram above, it looks like they are 7.5 volt ???

Thanks

Deblen

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deblen wrote:


Strobes are had to find in Australia. (240 volt). If I purchase them from the US (110 volt),




G'day Len, I hope that you and Deb are both well.

I use approx 40 strobes in my display spread across 2 LOR channels and they are very effective. I wasn't able to find any suitable strobes in Australia, so I purchased mine from the US and they are 110V. I use 2 x 240V > 110V step down transformers (from DSE), one for each channel, which work fine. The only hassle (from an Aussie perspective) is that the strobes I use have a C9 socket which meant having to purchase the C9 sockets from the US as well.

If you want the details of where I purchased the bits from drop me a PM and I'll shoot you over the info.

It might also be worth having a quick search through our Aussie forum archives as I remember about 12 - 18 months ago a few of the guys were playing with some 12V strobes purchased locally. I'm not sure what success they had or what they used for a power supply.

One other thing to consider is the flash rate. I remember Art was playing with some that only flashed approx once per second, or less, which to me (and him) wasn't very effective. The ones I use flash at approx 2 - 3 times per second which worked well.

Cheers,

davidt

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BadSCRm,

I just applied ohms law to the numbers you provided, but ignored the 7.5vdc for the moment.

20 ohms x .208 A = 4.16 volts and 16 ohms x .208 A = 3.328 volts. Now adding those two voltages 4.16 and 3.328 = 7.488, or for all practical reasons 7.5 volts that you said you applied. So, how is the strobe suppose to work? You have dropped all of your voltage in the resistors.

Like I said before, your math has a problem. But now it is not wattage, it is kirtchovs (SP?) law. This law states that in a series circuit that "The sum of the voltage drops, shall equal the voltage applied".

So, I'll try to help you find the answers wtih a few questions. What is the voltage drop across the 20 ohm resistor. To find this, put your volt meter across the 20 ohm resistor. What is the voltage drop across the 16 ohm resistor. Again with the volt meter probes on either side of this resistor. And again what is the voltage drope across the strobe module. Again with the probes on either side of the strobe only.

My friend, till we get the basics hammered out. Things can get crazy once you start working with high voltage.



To my down under friends. I do not know if this is the answer or not. But have you considered putting two 110VAC strobes in series. Then put some of these series circuits together with others in parrellel? The only problem with this is that if one goes bad, the other will go out too. But only in pairs, so it should not be that hard to figure out which one. Not like trying to find out which of 35 went bad like some of our light strings are wired with 35 in series. Sure would save some on the step down transformer. Esp if it is a large load (Amps) meaning you would need a transformer big enough to carry the current. Not cheap and they do get somewhat heavy and expensive.

Max

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Max-Paul
I see what you are talking about, the voltages you give are right,
With the two resistors they devide the voltage between them, if there was just one resistor there would be a Full 7.5Volts across it.

With capacitors: Have to use supper position, have to replace the capacitor with a Short, inorder to do the Calculations.




deblen
Strobe are 240Volt strobes anyhow.
(basic strobe Power supply, capacitor, Triger-Coil, Xeon tube)

The easy way to convert 110Volt strobes to 220Volt strobes is to Bypass the voltage dobbling part of the circuit, But keep a Diode going to the main capacitor.

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deblen wrote:

H,

Thanks for all the replies, now you have me wondering about the voltage.

Strobes are had to find in Australia. (240 volt). If I purchase them from the US (110 volt),

To run them I would need to get a 240 to 110 volt convertor, then use this to power them, or do they need to be reduced again to a lowerr voltage.

I think I will put some on the same channel, others on a defferent channel.

Might end up using 6 or 7 LOR Channels on the strobe effect.

Any tips on the voltage setup you are using. Can I just step down to a lower voltage or does it have to be 110 volt.

By the diagram above, it looks like they are 7.5 volt ???

Thanks

Deblen

The best thing to do would be to use a 240V > 110V step down transformers.



My strobes a very rare, mainly mine are defects.

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BadSCR wrote:

Max-Paul
I see what you are talking about, the voltages you give are right,
With the two resistors they devide the voltage between them, if there was just one resistor there would be a Full 7.5Volts across it.

With capacitors: Have to use supper position, have to replace the capacitor with a Short, inorder to do the Calculations.




time out for a second. I need to get a better picture of this. Am I right to say that you have a series circuit of 3 items? a 20 ohm resistor, a 16 ohm resistor and a strobe, is this not correct? Or, are you talking about a voltage divider with the strobe circuit in the middle of the two resistors?

If it is the first were all three are in series, then the cap becomes short of mute. For it will spend some time charging via the charging circuit and a short time discharging. But in either case the charging circuit will remain an almost constant load.

Still for this exersize it would be nice to know what the supply voltage is, what the voltage drop is across each item (R1, R2, & S1).



Max

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Ok, Lets recap.

Original Strobe: Vs-----> R1 ----> Strobe -----> Ground
Running on 7.5Vdc and pulling 375mA
The 20-ohm 1-watt resistor has 7.49Vdc drop (7.49Vdc*375mA=2.81Watts)



Modified Strobe: Vs-----> R1 ----> R2 ----> Strobe -----> Ground
Added a 16-ohm 5-watt resistor in series with the 20-ohm resistor.
Running on 7.5Vdc and pulling 208mA
The (R1) 20-ohm 1-watt resistor has 4.16Vdc drop (4.16Vdc*208mA=0.865Watts)
The (R2)16-ohm 5-watt resistor has 3.33Vdc drop (3.33Vdc*208mA=0.693Watts)
R1+R2=Vs 4.16Vdc+3.33Vdc=7.49Vdc kirtchovs law


I added a resistor and it fixed the over heating problem with the 20-ohm resistor.
I don't fully understand this strobe, There is some kinda feedback loop.

The pic is the Original Strobe schematic.








Attached files 172199=9858-Strobe Schem.jpg

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Well all I can say is that from the math. It appears that only about .01 volts is being applied to the strobe it's self. And I am having problems with the thought that this circuit could run on that low of a voltage. With the charging and firing of the strobe in A-stable mode. I would think that the load would be fairly constant. And the turning on and off of the primary side of the transformer more than likely will be in the Khz range. This would leave us with a fairly predictable reading on a DVM or even a VOM. Though the true voltage drop might be slightly higher, but we are not seeing this in this case. So the question is, what is the true voltage being applied to the strobe.

In your reply. You state the voltage across R1 and R2. Is this a physical value or a calculated value? Did you do a physical voltage reading across the strobe?

As for the feedback. Well one case is the oscillator that is jacking up the supply voltage to a few hundred. The second feedback is a simple one of monitoring the voltage across the cap via the neon bulb.

Max

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The reading are physical. (I use another DVM thinking that the first was wrong)

The strobe makes a high pitch noise

some other readings:
The transistor has 1.48Volts drop from C to E
The transformer has 1.63Volt drop on the primary side

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