Readergraph Chaser Lights

[stillwave]

Currently we have chaser lights around the readergraph of our 1930's venue, they are a very bespoke system to try & match the look of the original 1932 system requiring the lamps to come from the OEM.

 

I'm trying to source an off the shelf solution to either new replacement lamps or part/whole of the system to enable more standard similar looking lamps to be utilised, if one exists?

 

They currently are arranged as a 4 channel chase with a 3 on 1 off pattern. The lamps are a single chip LED (3w, Warm White) inside an opaque dome in the shape of an A60 lamp with cast aluminium body into a E27 base but they run at 9v DC (centre positive) the wiring looms are standard flat 2.5mm festoon cable with pre molded E27 sockets.

 

On the driver end they are controlled from a custom DMX controller feeding DMX decoders which in turn feed MOSFET cards ~10vDC (to account for the volt drop on the cable run) which output to the 232 x Lamps.

 

Technology having advanced a little since they were installed nearly a decade ago (to where there are now more varieties & even led 'filament' style lamps for example), any pointers for potential suppliers or the search terminology to use would be great. I've looked at fairground lights which might fit the bill if they did opaque 60mm diameter domed shaped caps for them but am I going down the wrong rabbit hole?

[Jivemaster]

OnSolar have had some BC LED pigmy lamps http://www.onsolar.co.uk/OnSolar-Specials.htm whether they would function on 9v??? Whether they will have more or others like ???

 

IMO your problem will be that the vast majority of low voltage LED systems are 12v for the convenience of using a car 12v battery. Some lamps will run dim, others will not run on 9v.

 

It's likely that the OEM supplier will be one of very few suppliers of spares.

[alistermorton]

Are you intending to replace the driver too, or just the lamps?

[stillwave]

If replacing the driver would mean being able to utilise more widely available standard lamps it would become more cost efficient going forward, yes we would. It doesn't even have to be LV but I was under the impression switching mains voltage LEDs thousands of times a day probably will make the LED lamps fail sooner?

 

It was a niche market even back then but with solar becoming more of a widespread market & LEDs improving dramatically over a decade I'm hoping that there's now a more standard solution even if it requires new drivers etc.

 

I've tried some 12v solar lamps but whilst they did light (& signifying brighter than the OEMs, even the lowest wattage ones!) they tripped the breaker, they're used outdoors (obviously) so was thinking that perhaps the lamps I tried weren't designed as outdoor lamps or if there's a voltage regulator in them, the current the lamps were trying to take @9v was too great?

[Jivemaster]

Battery technology is predominantly 12V and 9v must be a really odd number for battery use. Probably there is a bigger question to ask about the future of the whole unit, as is, or updated. Is the original OEM lamp still available, should you have a plan for when it is no longer available.

[IRW]

OK, I've been watching this hoping someone else would ask, but what on earth is a readergraph? Putting it into google doesn't bring up much likely stuff!

[ImagineerTom]

the industry name for the changeable sign on the front of a cinema that tells you what's showing. Like hoover it was once a specific term for a specific piece of equipment but is now a generic term for cinema signage.

[stillwave]

Jivemaster hit the nail on the head there! lamps are still available (but damn expensive per unit) but good to have alternatives hence wanting to move towards a more standard lamp / system.

[MarkPAman]

OK, I've been watching this hoping someone else would ask, but what on earth is a readergraph? Putting it into google doesn't bring up much likely stuff!

 

Don't worry, you're not alone!

[timsabre]

LED filament lamps are mains only due to the way the LED filaments work (they're basically a whole load of LED dies in series)

 

Mains would remove a lot of problems with volt drop and non standard bulbs, but you would have to consider if the rating of the installed cabling/lampholders was suitable, and issues with waterproofing etc assuming this is outside.

You could then use a standard DMX switch pack. I don't believe there would be any reliability issues with switching mains-rated LED lamps, no worse than LV anyway.

[bigclive]

On one hand I like the idea of the modern filament style LED lamps with their retro-shaped glass globes, but as Tim has mentioned it would require a full rewire for mains voltage with suitably waterproof lamp holders. There's also the issue of the suitability of the LED driver to being flashed. Some of the filament style lamps use a very basic capacitive dropper, some use a miniature buck regulator and some use an active chip that is basically a voltage regulator that simply dissipates the voltage difference between the mains and LEDs as heat. The third one is a good choice. Choosing a "dimmable" lamp would probably be a good option just for its more flashable circuitry.

 

Fairground caps might be a good idea too, and they do opal ones, although they lack the zing of the clear ones. In the UK the lamps are usually 60V wired as series multiples of four to make up the desired voltage. This has three advantages. It lowers the voltage across the lamp holder, reducing the risk of internal arcing and also takes some of the bang out of one lamp failing since there are three others in series. That was mainly advantageous with tungsten lamps but is also a good idea with LED lamps too. The third advantage is that the lower voltage tungsten lamps were more robust and it also makes the circuitry in the LED version a lot simpler too. Often the fairground caps are just a rectifier, LEDs and resistors. That makes them very suitable for flashing.

If you go the fairground cap route then make sure you get them from a known source like Imel Park. There are three types of the LED lamp floating about. One is just a bare PCB soldered onto a lamp base and will deliver a full mains referenced shock if you try to screw one in or out while powered. One is a fully potted module and the third is a compromise that has the bare PCB but dipped a few times in resin to insulate it and make it waterproof.

 

The fairground route would also require rewiring with the slight extra complexity of there being four chasing circuits, but also there being four lamps in series (about 9 wires along the run). The wiring is usually an insulation displacement system where you lay singles into the backs of the caps and then screw the lid on to pierce the wires and make the connection. It tends to look a bit "industrial" round the back, but that's just the nature of that system. Ideally the lamp number would come into a nice round multiple of the 16 lamps per section. Any that don't will have to be mounted on the back of the sign to make up the numbers.

[Jivemaster]

Is it worth looking at buying enough lamps of the OEM design to carry you through for a couple of years?

 

Few LEDs are made for 9v and if you buy say 100 of a new sort you'd have to hope they were still available after the usual LED lamp life.

 

What is the chance that someone will decide to revamp the whole frontage?