LED Dimmer for Backlighting

[ian@737ng.co.uk]

hi chaps........
funny JWS asked about this.   i've been in the 'Lab' this week working
on exactly the same thing        
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

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



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 
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

[fordgt40]

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

[dnoize]

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

[Sean]

The link doesn't work for me Stef.

[dnoize]

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

[XOrionFE]

great deal.   Thanks for the link Stef.  I ordered a few as this was on my to do list.

Scott

[NAX228]

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

[XOrionFE]

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.

[fordgt40]

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

[NAX228]

Thanks for the confiramtion David. I think I will go with a few of these.

[dnoize]

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

[jskibo]

Thanks for the links, grabbed three to check out!

[Kennair]

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.

[JWS]

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 

[fordgt40]

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

[NAX228]

Ordered 3 for stats myself. Too good price to not test out.

[ian@737ng.co.uk]

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 
rgds ... ian

[pebo]

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  ). 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 

[XOrionFE]

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

[jackpilot]

Scott
I may be wrong but the 777 overhead uses green Leds for the IBL's.
The 737uses bulbs.
JP

[XOrionFE]

oh,  that would make sense then.

[pebo]

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!

[ETomlin]

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?

[saabpilot]

Hi,

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

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

[ETomlin]

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.