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Main => General Discussion Board. => Topic started by: ian@737ng.co.uk on August 21, 2010, 09:22:46 PM

Title: LED Dimmer for Backlighting
Post by: ian@737ng.co.uk on August 21, 2010, 09:22:46 PM
hi chaps........
funny JWS asked about this.   i've been in the 'Lab' this week working
on exactly the same thing  ;D   ;D   ;D
just a cheap and simple solution to a dimmer for LED Backlighting.
i use these LED strips which are 12v operation and can be cut into
any length in groups of two LED's (i.e. 2,4,6,8 etc).  onboard diodes.
http://www.rapidonline.com/Electronic-Components/Optoelectronics/LED-Strips/Flexible-LED-strips/78784 (http://www.rapidonline.com/Electronic-Components/Optoelectronics/LED-Strips/Flexible-LED-strips/78784)

all i did was to run the feed to the strip thru a 470 ohm pot -et voila  ;D

(https://www.cockpitbuilders.com/proxy.php?request=http%3A%2F%2Fwww.737ng.co.uk%2Fdimmer.jpg&hash=70dfe4aaa26e0f1a84aeebdd5a11d1fe91399b57)

12v is fed into the pot thru the lower terminal and out to the strip from
the centre one.    GND is fed to the pot thru the upper terminal and then
down to the strip.      works a treat.   turn the pot clockwise and the LED's
get brighter, turn it anti-clockwise and they dim - simple  ;D
if you want your dimmer control the other way round, simply swap the 12v
and GND connections.

because of the current flow, i have however limited the number of LED's
to 10.   but that's ok, because they are very bright and have a 120 degree
throw.    so that does the job for me.

you can also use standard LED's, but resistors have to be fitted to the
supply voltage from the pot (on the board) to the LED's

hope that helps someone out

rgds and good luck ....

ian
Title: Re: LED Dimmer for Backlighting
Post by: fordgt40 on August 21, 2010, 11:46:43 PM
To supplement what the "Master" was saying, if you want to control a larger amount of current ie more 12volt led strips then this item on EBAY will do the trick very well- it is controling around 300 leds in my overhead

http://cgi.ebay.co.uk/12v-12-v-LED-strip-light-DC-dimmer-12-volt-8a-US-seller-/360276691806?pt=LH_DefaultDomain_0#shId

It is also often available direct from China, is well made and the internal electronics and pot can be removed from the case and incorporated into your own build.

David
Title: Re: LED Dimmer for Backlighting
Post by: dnoize on August 22, 2010, 01:05:44 AM
The dimmers linked to by david are great. I used quite a few of them in the past and you can hook up loads of leds to them.

But 'oops', the price. I hope nobody hit the 'buy it now' button.
9$ plus 26,50 $ shipping for us europeans :-(

Here is a cheaper link, 1 $ for the dimmer and 4,99 $ shipping worldwide, so even cheaper for americans ;-)

(perfect example of how much profit is made on electronics though ;-)

http://cgi.ebay.com/LED-Light-Dimmer-Brightness-Adjustable-Controller-12V-/400146244509?pt=LH_DefaultDomain_0


Exactly the same units (except for the black knob,  but you can find those on ebay for the same price). They ship lightningfast (i got mine in a week or so).
They ship them seperately so dont be surprised if you order more and get one. The rest will follow the following days ;-)

I have a number of these running quite a while now (not in the sim though, but on other projects), some having hundreds of seperate leds (with built in 12v resistor) others running numerous leds strips. They run continuously for the entire day and none of them has failed yet.

Please note these are 12V led dimmers. So you cant hook them up directly to a led without using a resistor.
common led strips use 12 volts by default so no problem there.

Stef

Title: Re: LED Dimmer for Backlighting
Post by: Sean on August 22, 2010, 01:18:18 AM
The link doesn't work for me Stef.
Title: Re: LED Dimmer for Backlighting
Post by: dnoize on August 22, 2010, 01:29:52 AM
weird. If i use the ebay button of this forum the link doesnt work, but if i paste it directly it does.

Anyway, edited the link above (without the use of ebay button), but here it is also:

http://cgi.ebay.com/LED-Light-Dimmer-Brightness-Adjustable-Controller-12V-/400146244509?pt=LH_DefaultDomain_0

Stef
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on August 22, 2010, 03:20:32 AM
great deal.   Thanks for the link Stef.  I ordered a few as this was on my to do list.

Scott
Title: Re: LED Dimmer for Backlighting
Post by: NAX228 on August 22, 2010, 06:17:54 AM
hmmm...I thought we had to use PWM (pulse) dimmers for LED strips.
Like this one:
http://cgi.ebay.com/ebaymotors/Dimmer-switch-12v-DC-LED-and-panel-lights-6-amp-PWM-_W0QQcmdZViewItemQQitemZ140439193274QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ht_573wt_1165
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on August 22, 2010, 06:52:11 AM
Probably depends on how many and how much the current draw will be for all of them.   I do plan on using pwm for controlling my FDS IBL panels like Ivar is doing but those are incandescent bulbs not led and draw much more current.
Title: Re: LED Dimmer for Backlighting
Post by: fordgt40 on August 22, 2010, 07:09:07 AM
NAX228

The dimmer I posted is PWM. I am also certain that the one posted by Dnoize is identical, just a different source and knob colour and of course cheaper. They work perfectly for me with over 300 leds in strips

David
Title: Re: LED Dimmer for Backlighting
Post by: NAX228 on August 22, 2010, 07:28:31 AM
Thanks for the confiramtion David. I think I will go with a few of these.
Title: Re: LED Dimmer for Backlighting
Post by: dnoize on August 22, 2010, 08:27:50 AM
Quote from: fordgt40 on August 22, 2010, 07:09:07 AM
NAX228

The dimmer I posted is PWM. I am also certain that the one posted by Dnoize is identical, just a different source and knob colour and of course cheaper. They work perfectly for me with over 300 leds in strips

David

Thats correct. These are both identical and both pwm. i have a couple of 100 leds burning with them too and no problem at all.

Stef
Title: Re: LED Dimmer for Backlighting
Post by: jskibo on August 22, 2010, 08:45:31 AM
Thanks for the links, grabbed three to check out!
Title: Re: LED Dimmer for Backlighting
Post by: Kennair on August 25, 2010, 04:15:19 AM
Quote from: fordgt40 on August 21, 2010, 11:46:43 PM
To supplement what the "Master" was saying, if you want to control a larger amount of current ie more 12volt led strips then this item on EBAY will do the trick very well- it is controling around 300 leds in my overhead

http://cgi.ebay.co.uk/12v-12-v-LED-strip-light-DC-dimmer-12-volt-8a-US-seller-/360276691806?pt=LH_DefaultDomain_0#shId

It is also often available direct from China, is well made and the internal electronics and pot can be removed from the case and incorporated into your own build.

David

Wow, excellent thanks David, just bought 3! (obviously the cheap $1 ones though)

Ken.
Title: Re: LED Dimmer for Backlighting
Post by: JWS on August 25, 2010, 12:21:39 PM
Just took a look at the dimmers Stef pointed out on E-bay, but are these not too big to put behind the light panel where you have two light control knobs close together? Ian's solution seems much smaller and more likely to fit. But it's hard to tell from the pictures, I may be wrong.

JWS 
Title: Re: LED Dimmer for Backlighting
Post by: fordgt40 on August 25, 2010, 12:33:27 PM
JWS

As mentioned earlier, the electronics can be removed from the box - the controlling pot is also separate from the electronics. I use the internals behind the Panel pot on the 737 overhead. You can see this on page 6 on the link below. The dimmer electronics are to the right of the USB Hub in the picture

http://www.737ng.co.uk/djb/Overhead%20Article.pdf

David
Title: Re: LED Dimmer for Backlighting
Post by: NAX228 on August 26, 2010, 02:46:03 AM
Ordered 3 for stats myself. Too good price to not test out.
Title: Re: LED Dimmer for Backlighting
Post by: ian@737ng.co.uk on August 26, 2010, 05:51:38 AM
Quote from: fordgt40 on August 25, 2010, 12:33:27 PM

As mentioned earlier, the electronics can be removed from the box - the controlling pot is also separate from the electronics. I use the internals behind the Panel pot on the 737 overhead. You can see this on page 6 on the link below. The dimmer electronics are to the right of the USB Hub in the picture

http://www.737ng.co.uk/djb/Overhead%20Article.pdf

David

gentlemen.......
i've just read thru this article again and i have to tell you that apart from knowing David personally, apart from being a really nice guy (him not me), i have never met anyone with such a talent for perfection.
sometimes i wish i could come close.
i'm a great believer in complementing people who deserve it.

as far as my little idea is concerned, my solution fixed my requirement and the best part, it was cheap at GB£0.50 (about 60 euro cents or 75 us cents).   that suited me even better  ;D
rgds ... ian
Title: Re: LED Dimmer for Backlighting
Post by: pebo on September 03, 2010, 05:35:18 AM
Bought and received five of the 1$ dimmers from China and mounted two on my B777 PRO-M Series IBL overhead Panel.
Dismounted them from the casing and installed the pot's directly in the panel (fits like a glove  ;D). One for dimming the 12V led strips on the underside of my glare shield and another as well for the 5V FDS overhead backlighting. both works grate, both on 12V and 5 V without any modifications!

Cheapest alternative for dimming your led's I would think  8)
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on September 03, 2010, 06:08:46 AM
wow, it is actually working with the overhead IBL lighting as well?  Those arent LEDs....

I would think that the amp draw on those would smoke the dimmer.      I just bought 4 of these and recieved them.  I test with LED strips and they worked fantastic but I had not even considered using them for the FDS IBL panels I have due to them being higher amp draw non-led lighting and these dimmers specifically said for LEDs.     Can you tell if they are heating up at all?

Scott
Title: Re: LED Dimmer for Backlighting
Post by: jackpilot on September 03, 2010, 06:34:39 AM
Scott
I may be wrong but the 777 overhead uses green Leds for the IBL's.
The 737uses bulbs.
JP
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on September 03, 2010, 06:58:01 AM
oh,  that would make sense then.
Title: Re: LED Dimmer for Backlighting
Post by: pebo on September 03, 2010, 07:03:12 AM
Green Leds it is. Have been using them for several hours now and can confirm, no heat at all, 12V or 5V.
Just works grate!
Title: Re: LED Dimmer for Backlighting
Post by: ETomlin on September 03, 2010, 09:05:33 AM
This is excellent. I wonder how well it'd work with the very tine SMD LEDs? Im wondering if any resistors would be required for those?
Title: Re: LED Dimmer for Backlighting
Post by: saabpilot on September 14, 2010, 07:33:21 AM
Hi,

Just bought 10 of those.
Arrived in 10 separate parcels in a couple of days  ;D

http://cgi.ebay.co.uk/12v-12-v-LED-strip-light-DC-dimmer-12-volt-8a-US-seller-/360276691806?pt=LH_DefaultDomain_0#shId

Excellent dimmer and VERY easy to disassemble. 
When disassembled very easy to fit in e.g. the overhead since the PC board is separated from the pot.
The small inside board connects with the pot via an 8 cm ribbon cable. 
On the board are screw connectors for 12V in and (dimmed) 12V out.
Is rated 8 A at 12 VDC which should be more than enough for all needs to dim LCD:s.

Highly recommended !

Best,
Bjorn

www.boeing737sim.se
Title: Re: LED Dimmer for Backlighting
Post by: ETomlin on November 15, 2010, 07:14:57 AM
I just bought 2 of these finally. I am a real novice when it comes to electronics such as ohms, resistors, wattage, amperage, etc. If anyone can point me in the right direction for using these with a handful of smd LEDs that'd be appreciated because I want to avoid using a resistor on each LED if at all possible.
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on November 15, 2010, 07:32:27 AM
Hello Eric,

You will still need to put a resistor on each LED or at least on a grouping.  Your supply is 12 volts so probably most you could do is 3 leds to one resistor in series.

This is the page I always use to figure it out:
http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator (http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator)

I am using 3 of the dimmers you are showing and they work excellent.   

Scott
Title: Re: LED Dimmer for Backlighting
Post by: ETomlin on November 15, 2010, 08:35:45 AM
Okay, thanks Scott I really appreciate that.
Title: Re: LED Dimmer for Backlighting
Post by: XOrionFE on November 15, 2010, 09:50:11 AM
looking at the calculator again it looks like you can do it in Parallel...not in Series.    Parallel can support a lot more leds it seems but you start getting into much higher rated resistors.

Scott
Title: Re: LED Dimmer for Backlighting
Post by: NeoMorph on July 30, 2011, 04:40:48 AM
Bit of a thread res but just wanted to say thank you as I wanted a simple solution to dimming my panels. Just bought 3 of them from ebay...

http://www.ebay.co.uk/itm/LED-Bulb-Dimmer-Adjustable-Brightness-Controller-DC-12V-/260819499674?pt=UK_Light_Fittings&hash=item3cba0dba9a

That's for UK users btw... only £4.69 each. A bargain.

Cheers!
Title: Re: LED Dimmer for Backlighting
Post by: HowardBryant on July 25, 2013, 10:01:57 PM
Quote from: ian@737ng.co.uk on August 21, 2010, 09:22:46 PM
hi chaps........
funny JWS asked about this.   i've been in the 'Lab' this week working
on exactly the same thing  ;D   ;D   ;D
just a cheap and simple solution to a dimmer for LED Backlighting.
i use these LED strips which are 12v operation and can be cut into
any length in groups of two LED's (i.e. 2,4,6,8 etc).  onboard diodes.
http://www.rapidonline.com/Electronic-Components/Optoelectronics/LED-Strips/Flexible-LED-strips/78784 (http://www.rapidonline.com/Electronic-Components/Optoelectronics/LED-Strips/Flexible-LED-strips/78784)

all i did was to run the feed to the strip thru a 470 ohm pot -et voila  ;D

(https://www.cockpitbuilders.com/proxy.php?request=http%3A%2F%2Fwww.737ng.co.uk%2Fdimmer.jpg&hash=70dfe4aaa26e0f1a84aeebdd5a11d1fe91399b57)

12v is fed into the pot thru the lower terminal and out to the strip from
the centre one.    GND is fed to the pot thru the upper terminal and then
down to the strip.      works a treat.   turn the pot clockwise and the LED's
get brighter, turn it anti-clockwise and they dim - simple  ;D
if you want your dimmer control the other way round, simply swap the 12v
and GND connections.

because of the current flow, i have however limited the number of LED's
to 10.   but that's ok, because they are very bright and have a 120 degree
throw.    so that does the job for me.

you can also use standard LED's, but resistors have to be fitted to the
supply voltage from the pot (on the board) to the led lighting (http://www.niceledlights.com)

hope that helps someone out

rgds and good luck ....

ian


Hello friend the information will surely help me a lot.. I am working on similar project and hope the post will be huge assistance.. Thanks again
Title: Re: LED Dimmer for Backlighting
Post by: dc8flightdeck on July 26, 2013, 10:25:02 AM
very nice! ;)

Justin
Title: Re: LED Dimmer for Backlighting
Post by: jackpilot on July 28, 2013, 04:50:18 AM
These are widely used by builders.
You can remove the pot and install it anywhere on wires extension
Order a few as you can control various lighting areas that way.

[ebay]400539066105[/ebay]