EEVblog #361 - LED Ceiling Panel Lighting 101

How do LED ceiling panel LED lights work?
Everything you need to know about LED ceiling panel lighting, with Doug Ford.
And a bonus tutorial on underwater LED lighting.

Two more parts to this LED lighting installation coming soon...

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[RandyLott]

Doug sounds like a professional storyteller. Awesome!

[pikuorguk]

Doug's quite easy to watch. Nice and relaxed manner with good banter. More :-)

[Lachlant]

I really like these videos you've done with Doug Ford, I wish you'd do more of them.

[bigclivedotcom]

LED sales are still being driven by unscrupulous marketing departments. The intensity fall-off from even high profile brands can be quite surprising. If you do use those panels a lot then it would be interesting to get light readings from new and as they progressively age.
Then of course there are the cost-engineered power supplies.... The LEDs will often outlast the PSUs, which often fail in a strobing mode. Presumably due to dry caps causing excess ripple that triggers the overload protection repeatedly.

[aptsys]

Also notice the spec sheet says 24V. The mains converter efficiency also needs to be taken into account

[achemachew]

Light Emitting Diodes are my favorite! I've been playing with those since I was 10, and I'm amazed how far the have come! I love my RGB one that came in a cheap lighter! I flashes through the colors fast and slow without any components!

[rocketmanprojects]

I have noticed that too. I have some in a light over my desk that will do that. They are in series strings and sometimes the whole string will flicker but other times only one led will flicker. I have been replacing one every other week now.

[jonathanmlang]

A cheaper or even completely free DIY way would be to take a cracked or broken large lcd and replace the actual lcd panel with a thick plastic panel and remove the lensing sheets under it but leaving the diffuser. Most modern lcds use led backlighting and works in a similar way to this. It does work and you do get rather even light!

[TindallAndrew]

This helped me so much with my dissertation - honestly great stuff!

[JosQiNgMT]

I stay a hotel using this panel deco as a fake window. And it look so real and natural for a room which without a window and it work so well.

[FrankSiler]

Blue scattering is from Rayleigh scattering- see Walter Lewin at 57 minutes in "
Lec 14 | MIT 8.03 Vibrations and Waves, Fall 2004" on youtube

[aptsys]

Have you looked at the conditions needed to get 120lm/W efficacy?

[hodmt]

70Hz to 100Hz is when your eyes are still. When you move your eyes (or the light source) the light is hitting different parts of the retina, so there's no chemical limit. I've tested this with a 555 timer and a LED.

[qwaqwa]

Did you mention CRI? It's a very important measure of light quality too – not just "temperature".

[williamhayden]

Yes, depending on where you drill of course. The diffuser is just acrylic plastic. Drilling holes in it will not affect the function assuming you don't drill the electronic component, but it will affect performance. Drilling a hole will allow light leaks and thus the effects of the diffuser around this area will be lost.

[johnplacenet]

i have a question.. is it possible to drill a 1" hole in the material and it to still work?

[scotty]

You can't get hotspot in the middle. If you calculate second derivative of 1/(x+a)^2 + 1/(x-a)^2 for point 0 you always get positive number (regardless of a) and that means that there is always minimum in the middle.

[ForViewingOnly]

Thank you Doug, LED Guru! Very interesting... I learnt a lot.
I'd like to know Doug's opinion on LEDs for car lights... I played around with some recently and wasn't impressed, but I think I was sold crap that wasn't fit for purpose. White LEDs behind coloured light clusters definitely don't work, unless you like pink stop lights and green-tinged indicator lights :-). Dashboard LEDs are insanely high intensity too... blinding when driving at night.

[MadManMarkAu]

18:00 GOD DAMMIT, DAVE. Simply mentioning the nails-on-blackboard sound makes it play in my head. I shuddered SO HARD when you mentioned it. :)

[whitcwa]

I believe the change from magnetic to switching ballasts was to improve efficiency.