LED Practicals and dimming

[Zulu]

Hi,

there are lots of great looking low cost domestic LED lights these days, I'm talking about ceiling lights, floor lamps, table lamps etc.
I am considering using some as practicals on a theatre set, and wonder about control and dimming.

My theatre currently operates a mixture of trad fixtures, controlled through dimmers to my desk, and also theatre LED lights, controlled through DMX and my desk.

Question . . . Is it possible to control such domestic LED lights, which are dimmable in a domestic application with a dedicated dimmer switch, through my desk?

(I've attached an example of what I'm talking about)

many thanks, Zulu

[timsabre]

Short answer... probably not with the dimmers you already have.

Long answer, maybe, it depends on what your dimmers are - you may get problems with flickering or latch-on and you will get quite a sudden snap in when fading in from off. Dimmable LED only really dims well with trailing edge / MOSFET dimmers and nearly all theatrical dimmers are leading edge triac controlled dimmers. You can sometimes make it work better by putting a big halogen lamp on the same channel and hiding it away somewhere (a load lamp).

There are DMX trailing edge dimmers such as Artistic Licence's Sundial but they are quite expensive. You can get cheaper ones from china e.g. https://www.ebay.co.uk/itm/254595781271  which I have used and they do work, but depends on your venue's policy on potentially dodgy electrical gear of unknown origin.

[alistermorton]

The short answer is "It depends". 

Firstly, the lamp in the fixture needs to be dimmable, so if the fixture uses a non replaceable LED and it's not specifically marked as dimmable, then the chances are you're snookered. If it is dimmable, then the type of dimmer comes into play. Most theatrical mains dimmers are leading edge thyristor or triac dimmers, with a minimum load requirement. Most line dimmable LEDs work best on trailing edge dimmers that have been designed for LEDs, and there are DMX controlable versions of these.

What often happens with theatre dimmers is that as you dim up or down around 0 the LED will either flash or snap on or off - it won't dim smoothly. Sometimes even when the dimmer is completely off, there is enough leakage current to cause the LED to flash periodically. You also often find that the dimming curve is completely different to the curve with your tungsten lamps.

So give it a try and see, but be prepared for it to be imperfect.

E2A - Tim beat me to it ...

 

Edited May 5, 2022 by alistermorton

[Brian]

34 minutes ago, Zulu said:

there are lots of great looking low cost domestic LED lights these days, ... (I've attached an example of what I'm talking about)

 

What you've pictured isn't LED. It's a set of mains GU10 holders. (no lamps supplied)

So you could fit halogen GU10s lamps in there and not worry.

[Edward- Z88]

Hi @Zulu

34 minutes ago, Zulu said:

My theatre currently operates a mixture of trad fixtures, controlled through dimmers to my desk, and also theatre LED lights, controlled through DMX and my desk.

Question . . . Is it possible to control such domestic LED lights, which are dimmable in a domestic application with a dedicated dimmer switch, through my desk?

What lighting desk do you use? If you are using a Zero 88 console running ZerOS, the next software update will bring native support for controlling Philips Hue smart bulbs and smart plugs. See the link below if you're interested...

https://zero88.com/news/strand-and-zero-88-add-vision-net-color-kinetics-kinet-and-philips-hue-support-in-zeros-consoles

Edward

[timsabre]

5 minutes ago, Brian said:

What you've pictured isn't LED. It's a set of mains GU10 holders. (no lamps supplied)

So you could fit halogen GU10s lamps in there and not worry.

Ha didn't spot that. Although Halogen GU10's last about 5 minutes so that would be the main problem.

[Zulu]

Thanks, Guys.

2 hours ago, Brian said:

What you've pictured isn't LED. It's a set of mains GU10 holders. (no lamps supplied)

So you could fit halogen GU10s lamps in there and not worry

you're right, the fixture I showed comes without lamps of either type. But outside the scope of my screenshot, it recommends use of 25W LED Dimmable GU10 bulbs.

2 hours ago, Edward- Z88 said:

What lighting desk do you use? If you are using a Zero 88 console running ZerOS, the next software update will bring native support for controlling Philips Hue smart bulbs and smart plugs. See the link below if you're interested...

Ed, I use a Zero 88 FLX S24 desk, so I'll be looking at that link.

My Dimmers are Strand ACT6, and I'm familiar with using a dummy load to control low wattage lamps. But, seeing the comments on leading edge and trailing edge dimming, I don't think this would work on these type of LED lamps.

Extra question . . . Am I likely to damage my thyrister-based dimmers if I just plug the kit in, and try it?

2 hours ago, timsabre said:

There are DMX trailing edge dimmers such as Artistic Licence's Sundial but they are quite expensive. You can get cheaper ones from china e.g. https://www.ebay.co.uk/itm/254595781271  which I have used and they do work, but depends on your venue's policy on potentially dodgy electrical gear of unknown origin.

This maybe worth a look.

I feel there should be a way of using modern domestic products in theatrical settings, just like we used to with filament chandeliers, wall lights, etc.

Thanks, All, again

[Edward- Z88]

Hi @Zulu

17 minutes ago, Zulu said:

Ed, I use a Zero 88 FLX S24 desk, so I'll be looking at that link.

My Dimmers are Strand ACT6, and I'm familiar with using a dummy load to control low wattage lamps. But, seeing the comments on leading edge and trailing edge dimming, I don't think this would work on these type of LED lamps.

Extra question . . . Am I likely to damage my thyrister-based dimmers if I just plug the kit in, and try it?

If you choose to go down the Philips Hue route, you won't need to worry about dimming LED lamps.

Instead you can use a light fitting/fixture of your choice, and power this straight from the mains, not via a dimmer. You can then use a Philips Hue lamp of suitable style and lamp base in your fitting. In ZerOS 7.12 software, you will then be able to connect your FLX S24 to a Philips Hue bridge, and your Philips Hue lamps will then be automatically patched into your console. You can then control the Hue lamps just like a DMX fixture, with intensity and colour control, and record them into your cues.

Philips Hue lamps are available in full colour, tuneable white, and warm white variants depending on your needs. Smart Plugs are also compatible, to provide you with simple relays you can control from your console.

Please feel free to PM me if you'd like more information.

Hope this helps.

Edward

Edited May 5, 2022 by Edward- Z88

[sunray]

Totally crazy but I've seen one solution using a domestic rotary dimmerS and stepper motorS/PCB from a dead moving head fitting. It was built in a 2U rack enclosure and worked very well, but strange hearing them whizz round.

[boatman]

1 hour ago, sunray said:

Totally crazy but I've seen one solution using a domestic rotary dimmerS and stepper motorS/PCB from a dead moving head fitting. It was built in a 2U rack enclosure and worked very well, but strange hearing them whizz round.

A d0mest1c dimmer and a DMX servo board might work well too.

[J Pearce]

A standard domestic dimmer won't do anything a good theatrical dimmer cannot. Indeed many are far less civilised in their circuitry, and can't dim to true zero without that positive click at the end of their travel.

You can get dimmers that handle LED bulbs better than the average triac dimmer. These exist in domestic wallplate format and DIN rail format (and in formats to embed into boxes - I have some zwave units in my house). 

Tungsten and halogen fixtures have some inherent smoothing due to their thermal mass, LED doesn't so 16 bit control is far superior to 8 bit control. Similarly the dimming curves can be different to that which we are used to, so dimmers with adjustable curves are helpful (you can also do this at the console, but especially on 8 bit control this can leave you with resolution issues at one end of your fade).

Artistic license do some that are meant to be quite good, but I've not heard much real world feedback on them, so don't take this as a recommendation.

[timsabre]

2 hours ago, Zulu said:

Extra question . . . Am I likely to damage my thyrister-based dimmers if I just plug the kit in, and try it?

No you won't damage anything. But beware of variable results, I've had some dimmable lamps work fine during rehearsal then start to strobe randomly when they were supposed to be off during the actual show. 

[Bryson]

3 hours ago, Edward- Z88 said:

You can then use a Philips Hue lamp of suitable style and lamp base in your fitting. In ZerOS 7.12 software, you will then be able to connect your FLX S24 to a Philips Hue bridge, and your Philips Hue lamps will then be automatically patched into your console. You can then control the Hue lamps just like a DMX fixture, with intensity and colour control, and record them into your cues.

I didn't realize this was a thing you could do now.  My wife is going to be furious. 😉

[Ynot]

On 5/5/2022 at 4:36 PM, Edward- Z88 said:

Hi @Zulu

If you choose to go down the Philips Hue route, you won't need to worry about dimming LED lamps.

Instead you can use a light fitting/fixture of your choice, and power this straight from the mains, not via a dimmer. You can then use a Philips Hue lamp of suitable style and lamp base in your fitting. In ZerOS 7.12 software, you will then be able to connect your FLX S24 to a Philips Hue bridge, and your Philips Hue lamps will then be automatically patched into your console. You can then control the Hue lamps just like a DMX fixture, with intensity and colour control, and record them into your cues.

Philips Hue lamps are available in full colour, tuneable white, and warm white variants depending on your needs. Smart Plugs are also compatible, to provide you with simple relays you can control from your console.

Please feel free to PM me if you'd like more information.

Hope this helps.

Edward

Is this unique to Z88 desks?

Or is the proprietary software/control side native to Phillips, and therefore potentially available to those of us with other desks...?

[Edward- Z88]

Hi @Ynot

15 minutes ago, Ynot said:

Is this unique to Z88 desks?

Or is the proprietary software/control side native to Phillips, and therefore potentially available to those of us with other desks...?

We have implemented the Philips Hue API into ZerOS 7.12 software (scheduled for release later this year), to allow FLX range consoles to communicate with Hue bridges.

The Philips Hue API is well documented, which people have used for all sorts of control systems. For example I believe people have written scripts to convert Art-Net to Philips Hue API.

PM me if you have any questions.

Edward