Question Sequencing for Strobes

[jim6918]

Having never user strobes before and based on an earlier post, I have identified areas (mostly high points, or musical climaxes) in my existing sequences where I would like the strobes to fire.

I will have 25 strobes on 3 channels (could easily be more, as I have spare channels), that I want to place in a tall pine tree.

My question is: how to sequence them? I want the strobes to flash alternately or randomly when they fire, for example during the 10 second finale of the song. Should I have them come on at slightly different timings, say +/- .10 seconds for each channel? Or, do the strobes tend to fire at different times, so I should just set the 3 channels to on and off at the same times? I don't want all the strobes to fire at the same precise time.

Also is there any difference to setting the three channels to twinkle instead of steady on? Would that make the firing more random yet? I have a feeling that steady on is better since twinkle might be long enough for the strobes to build a charge and release.

[JBullard]

Jim,

To answer the last question first, only steady on, no effects on the strobe channels.

You didn't specify which strobes you have. How you sequence will depend on the stobes.

For the few remaining Christmas Light Show strobes I have left (have around a 25% or more failure rate with them every year- probably only about 10 - 15 left out of a hundred), I usually just had them all on one channel, since, in my experience, they started fairly random.

For Creative Displays LED strobes, I have them on a separate channel, with a small precharge just before they are needed so they fire random. I use these for "pinpoints of twinkling lights" since their light output is different then xenon tube based strobes.

I'm adding Creative Displays new Xenon based strobes this year that I acquired from the January presale. They will also have a small precharge so they will start random.

I have some of each type pulled out of storage right now since I also use stobes in my 4th July (as well as Halloween and Christmas) and I'm making some changes to the 4th display.

My suggestion is to get the strobes out, run your own tests, since all strobes are not created equal, as your experience with your stobes may be different then mine with the three brands and types that I have.


Over on Carolina Christmas we are doing lots of tests with these strobes right now. I'm doing stress testing on the new CDI Xenon strobes. Have one outside and one in the refrigerator.

See this thread that William posted:

http://www.christmascarolina.com/forums/showthread.php/1001-Strobes-CDI-vs-CLS

[jim6918]

JBullard wrote:

You didn't specify which strobes you have. How you sequence will depend on the stobes.

After I hit SEND I knew I should have added this info. Mine are the CDI LED strobes purchased new this year.

I suspected there had to be some kind of precharge.

So, hypothetically, if I want three channels to fire randomly during the last 10 seconds of a sequence, how far before should I start to precharge, and how far apart should I turn the channel to full on? And, at what power level should I precharge?

[JBullard]

Good questions Jim, the answer is "it depends", that's why I suggested running your own tests.

I find that precharging at about 20% power for 1/2 sec or so usually gives me good results with MOST of my CDI LED strobes. With some the 20% causes them to slightly glow and some of the others I precharge at 22 - 23%

The natural tolerance variations in electronic components are the reason. Hence I pretest mine, and label accordingly, and try to put "matched strobes" in the same string, for use on a particular channel. Can you say record keeping?

Here again, I would never attempt to tell someone how to sequence their strobes. I know what works for me, with my lights, and what looks good to me. Your style may vary.

[jimswinder]

JBullard wrote:

I'm doing stress testing on the new CDI Xenon strobes. Have one outside and one in the refrigerator.

Hope that pork you have in the fridge doesn't start having seizures!!! :shock:

[JBullard]

jimswinder wrote:

JBullard wrote:

I'm doing stress testing on the new CDI Xenon strobes. Have one outside and one in the refrigerator.

Hope that pork you have in the fridge doesn't start having seizures!!! :shock:

The pork is doing fine. But I had an email this morning from George. He's the little guy that lives in the frig that turns the light on when you open the door and off when you close it. He wants me to put in a service call, because he thinks that switch he flips is broken. He can flip it one way and the strobe turns off, but then it comes right back on, so he flips the switch again, and the same thing happens. Poor George, his fingers are getting tired and he can't even get any sleep in the middle of the night, like he's used to!

[jim6918]

I am resurrecting this thread because I have started adding timings for my strobes to existing sequences.

I am precharging my CDI LEF Strobes at 20% for about a second before firing them at 100%. I can vary this when I hang the outside lights.

My current question is: What is the shortest time you would want to fire the strobes and get any recognizable effect?

During static testing this summer (no controller and all strobes plugged into same circuit) that they take a short amount of time to start randomly flashing.

In my Mariah Careys All I Want for Christmas is You sequence, I was looking at firing them at timings that would be 2 to 3 seconds long, tops. Even with the strobes on 3 different channels, and staggering the start timings, I am wondering if I am going to get a real random strobe effect.

Sequencing strobes is the devil since you really can't see what they will do until you go live.


To be honest I am considering packing the strobes up and saying the hell with it.

I had originally wanted to put them all by themselves in a tall pine tree, but have grossly underestimated the quantity needed for a tree that tall.

[JBullard]

jim6918 wrote:

In my Mariah Careys All I Want for Christmas is You sequence, I was looking at firing them at timings that would be 2 to 3 seconds long, tops. Even with the strobes on 3 different channels, and staggering the start timings, I am wondering if I am going to get a real random strobe effect.

Sequencing strobes is the devil since you really can't see what they will do until you go live.


To be honest I am considering packing the strobes up and saying the hell with it.

Jim,

Way back in an earlier post, I suggested running tests with your sequence and your strobes.

I just hook up a controller, set it to the Unit ID I have the strobes programmed on, plug in a string of strobes, and play the sequence. I can then visualize how they fire in the sequence, and adjust my precharge (for the LED strobes) and how much lead time in the sequence to give them to fire.

[Al in Raleigh]

By precharging the strobe you are giving an RC circuit a small charge that allows "randomness" to the process. If you vary the voltage and charge times the circuit will do the same. The trick is to not give the strobe too much voltage for too long. Play with the strobe to get an idea. A change in temperatures could change the precharge characteristics. I spent quite a while reverse engineering that circuit and found the components to have a wide tolerancing. That wide tolerancing is what allows this precharging to simulate random firing. To answer your question, about 0.2 seconds worked for me on a small sample size of strobes.

I also spent a great deal of time on the CDI xenon strobes. May I recommend the xenon as they do not require precharging to random fire. The CDI strobes enclosures are far superior and worked perfectly in our outhouse, environmental testing. The CDI strobes are far more mechanicallyrobust than the CLS strobes. The mechanical failure rate and condensation problems of the CLS strobes are unacceptable. That is why I now own a bunch of the CDI xenon strobes.