Panel Backlighting and MIP Lighting Question

[hladamjr]

I am building an EFIS, the first of many panels for a 737. I am using the EFIS panel from Manolo at Hispapanels and two dual concentric encoders two single encoders and tactile switches. I've modiied the layout of the panels and switches somewhat from the tutorial on his site. I've looked and haven't seen much in the way of threads as far as I could find relating to panel back-lighting and have a couple of questions.

I would like to make all of the panels I build backlit and would like to use LEDs if at all possible but want to be able to dim them. I understand about LED's and voltage drop and wondered how others have accomplished dimming with LED's or do you not worry about dimming them. I don't necessarily want to use incadescant bulbs but it would be easier but also increases the heat factor. I've also seen where some have suggested EL wire but haven't seen that many pro's or cons on that plus I'm not aware of any relatively inexpensive way to dim EL wire also. Most of the panels don't allow much room for LED self adhesive strips but if that is what others suggest or live by then I'll take that suggestion too and work them into the design

Basically I'm looking for suggestions/how'to's what works and what doesn't and always the " if I had to do it again I'd do it this way story" . I'm not looking for the cheapest way but something that is reliable and time tested and low maintenance.

I saw a short demo video somewhere of an FMC with keypad dimming and wondered what was used for that as I plan on building my FMC also. I am pretty adept at electronics assembly just somewhat short on recent electronics circuit design. I have seen the article here on LED dimming and wondered if others use this type of circuit for backlight dimming.
http://www.mikesflightdeck.com/led_dimmer.htm

Thanks in advance

Hank Adam

[davek]

Hi Hank

I bought this unit (http://www.virtual-village.com.au/search?VIEW_SIZE=10&PAGING=Y&SEARCH_OPERATOR=AND&SEARCH_STRING=led+dimmer&SEARCH_CATEGORY_ID=RootCatagoryAU)
which works well with 12v.

http://images.virtualvillage.com/001480-158/001.jpg?s=272

I have a 12v circuit for the cabin lighting and will use 12v premade LEDs. (too lazy to solder so bought them off ebay) for the backlighting of panels.

It performs well as I say with 12v but not sure about 5v or less with LEDs. I dont have a 5v power source or 5v LEDs to try it sorry.

[Joe Lavery]

I used the circuit design attached to dim the LED lighting on my 737 flight deck. It works perfectly and cost just a couple of pounds in components.

Hope that helps.

Joe.

[hladamjr]

Thanks for both of the responses. I may be able to incorporate both idea's or methods. I like the circuit. Just curious how many LED's your both running with them and whether their for backlight or front panel illuniation or both.
I'd like to be able to use a circuit type on my FMC for backlighting. The dimmer pot is panel mounted on it and the board I could work into it rather easily or mount it behind it even. I was thinking of using LED strip if possible which would make it easier thn messing with a bunch or resistors. Something like these possibly:
http://www.superbrightleds.com/cgi-bin/store/index.cgi?action=DispPage&Page2Disp=%2Fspecs%2FFLS.htm

Thanks again

Hank