make a strip light flicker

[vandenberg]

Hello,

 

I am a technician and also an artist working in the field of sound/light installations.

 

For the project I am currently working on I need to make 6 x 5ft strip lights flicker on demand.

 

I know you are not supposed to plug flouro lighting into conventional dimmers ( stage dimmer packs or domestic dimmer), however I have tried this and with the dimmer at 50% ish I get good flickering results.

 

However, I am a little worried I will kill my dimmer pack doing this for a long length of time. I need these strip lights to come on and flicker for about 5 seconds every couple of minuets for about 12 hours a day.

 

My questions are :

 

will this kill my dimmer ? ( is it theoretically dangerous due to capacitive load?) ( does it actually exert a capacitive load ??)

 

Does anyone know a better way? ( I have contemplated using a variac but I assume I need DMX control to automate this as I dont want to be twiddling a variac for 12 hours!)

 

Any thoughts/help, greatly appreciated!

 

Thanks

Bob

[dbuckley]

Have as look at the Blue Room Wiki page on Fluorescent lights

 

If you decide to use a VIP90 ballast solution then there is a blue roomer who may be able to sell you one or more.

[jonic222]

Not personally tried this, but could you wire it through a DMX switch pack and program a flickering chase through the switch pack (or simply hit the flash button a few times)

[adam2]

A full size (4, 5, or 6 foot) flourescent lamp may be made to flicker by connecting it in the usuall way to a choke and starter, but useing the wrong starter. Use a starter intended for use with a series pair of 2 foot lamps, these are widely sold as "series starters"

 

If the lamp is only required to flicker at times, being lit normally at other times, then use 2 starters, one correctly rated for the lamp, and one intended for a series pair of lamps.

The correct starter may be permanently connected to the lamp, with the incorrect one being wired in parralel with the correct one and controlled by a switch, or relay if remote control is required. By useing a number of relays, any number of lamps may be lit normaly or made to flicker. They should all flicker independently, whereas other methods may result in them flickering together.

 

Take proper care with mains voltage, and remember that the "wrong" starters must be the old fashioned and very cheap ones known as glow starters, the more modern electronic starters wont work.

[timsabre]

We could design you a little circuit to do this which could save a lot of messing around, it would be a fairly simple thing to do with a microprocessor and a few triacs. - PM sent.

[vandenberg]

Many Thanks for all the help.

 

I did look at the Wiki, very helpful thanks. I am trying to avoid the costs of hiring/buying proper flurry dimmer ballasts. I recently saw an artist using the dimmable flurries from sparks hire and they were very impressive. However the effect I want to create needs to look just like malfunctioning strip lights flickering and I think the proper flurries will not look random enough and I may get lights flashing together instead of independently.

 

I like the idea of using the wrong starters. I shall get some and test. Adam2 - do you know the wattage rating of the correct 'wrong' series starters ?

 

I don't need the lights to come on properly at any point so just using the wrong starters would be an easy option. I imagine if I combine this with a DMX switcher/dimmer that turns the individual lights on for a few seconds every minute or so I would have what I need.

 

Would this be ok electrically, for the dimmer / switcher ?

 

Would it be better to go for some sort of a relay/timer to turn the lights on/off instead of DMX programming ?

 

Many Thanks

Bob

[dmxtothemax]

Some dimmers can cope with reactive loads and some cant.

it is best that you contact the dimmer manufacturer and ask them.

Also using a incandesant lamp as a counteractive load also helps.

Try it and see, most good quality dimmers will cope with reactive loads.

But if its one of those cheap four packs I would be wary.

 

Hello,

 

I am a technician and also an artist working in the field of sound/light installations.

 

For the project I am currently working on I need to make 6 x 5ft strip lights flicker on demand.

 

I know you are not supposed to plug flouro lighting into conventional dimmers ( stage dimmer packs or domestic dimmer), however I have tried this and with the dimmer at 50% ish I get good flickering results.

 

However, I am a little worried I will kill my dimmer pack doing this for a long length of time. I need these strip lights to come on and flicker for about 5 seconds every couple of minuets for about 12 hours a day.

 

My questions are :

 

will this kill my dimmer ? ( is it theoretically dangerous due to capacitive load?) ( does it actually exert a capacitive load ??)

 

Does anyone know a better way? ( I have contemplated using a variac but I assume I need DMX control to automate this as I dont want to be twiddling a variac for 12 hours!)

 

Any thoughts/help, greatly appreciated!

 

Thanks

Bob

[adam2]

If you dont need to the flourescent lamps to light normally, but only to flicker, then this is very easy.

 

Simply obtain standard switch start flourescent fixtures, for 4,5, or 6 foot lamps, screwfix direct have them very cheaply. Be certain to get the cheap basic type of fitting known as "switch start" the ones that have a starter mounted in the side of the fitting.

 

Replace the supplied starter with one rated for a series pair of 18/20 watt lamps, these are sold by all electrical wholesalers and are variously known as "series starters" or "110/120 volt starters"

The lamp will flicker on and off, making repeated failed attempts at starting.

 

I would control the lamps with a manual switch, or a DMX controlled relay, not a dimmer.

 

If you wish to view the effect before spending more than £1, look for a suitable fitting in your home or workplace, insert the wrong starter and observe.

[Jivemaster]

Can you use a strobe? They will flash exactly on demand, and can be triggered by a programmed controller to flash to programme. Also the tube is meant to flash and the control gear suits this purpose! Build a strobe into the fluorescent fitting as well as the tubes.

[Jamtastic3]

Can you use a strobe? They will flash exactly on demand, and can be triggered by a programmed controller to flash to programme. Also the tube is meant to flash and the control gear suits this purpose! Build a strobe into the fluorescent fitting as well as the tubes.

 

I don't think a strobe would work.

The flash rate is incredibly fast and and they give off a completely different light and colour output.

You could possible get away with strobes if the strobes were Atomics, as they have the blinder mode.

[Jivemaster]

It could work if you could chose single flashes like photo flash It would then flash exactly to cue and the fluorescent could also go on and off to cue with some (false) flickers.

[vandenberg]

Thanks again for the tips and ideas

 

Unfortunately I need to use real Strip light fittings as opposed to strobes...etc I had suggested LED batons as an alternative but I'm afraid it has to be real fluorescent strip lights as we will be using magnetic coils to pick up the 'sound' of the tubes striking.

 

I think the DMX relay/switching of tubes flickering with wrong starters is the best way to go.

 

http://cpc.farnell.com/milford-instruments...itch/dp/HK00998

 

These look like the right things but I will need 6 and they do not appear to have DMX out for daisy chaining, so I assume I would need a DMX splitter. The cost of these relays + DMX SPLITTER seems to be higher than a dedicated switching unit like this (discontinued, but available on ebay for £50 every so often):

 

http://www.martinpro.co.uk/product/product...t=dmxswitchpack

 

All good.....

 

HOWEVER....

 

This unit clearly states in the manual, that it is not for use with Fluorescent or other Discharge lamps, the use of these can break the unit. This brings me full circle to my original problem of not wanting to damage a dimmer pack.

 

dmxtothemax mentions in his reply that some dimmers are ok with 'reactive loads' does this mean they are ok with Discharge lighting' ?

 

He also mentions that using conventional tungsten lights as counteractive loads can help. This is something I have heard of...

 

So I suppose my next questions would be :

 

Can anyone recommend a Dimmer/switcher that is OK with reactive loads / discharge lamps ?

 

Or could I use one like the Martin linked to above, and simply add a counteractive load to 'protect' the switcher/dimmer ?

 

I understand I am at the point of needing to Buy and Try. However even killing a small DMX switcher will cost me £50 so any good LX advice before I just start plugging stuff together would be valuable....

 

Many Thanks

Bob

[smalljoshua]

How about an 8 Channel version of the Milford unit you found?

 

http://cpc.farnell.com/milford-instruments...oard/dp/HK00855

 

Josh

[bruce]

http://cpc.farnell.com/milford-instruments...itch/dp/HK00998

 

These look like the right things but I will need 6 and they do not appear to have DMX out for daisy chaining, so I assume I would need a DMX splitter.

 

Just wire the DMX in and out in parallel.

[vandenberg]

Thanks Josh the 8ch kit is a 30v DC relay as opposed to a 10amp 240v switch.

 

Thanks Bruce, I just assumed you couldn't just chain DMX like that but if you can that's great...

 

Thanks

Bob