Hi all,
I'm trying to fit a lot of LED's about 30 to a car gauge that has a diameter of about 110mm.
I was thinking Flexible PCB so I can use SMD LEDs, but cant find anyone to make it! And dont really understand the instructions (or have every done any PCB making before) so don't want to try it myself.
Anyone got any ideas how I could do it either get them printed by a company? (anyone know one in the UK?) or how to DIY?
Thanks Rob
You mean something like this?
This is 30 5 mm LEDs in about a 2" circle, would easy to spread out more.
6 columns of 5 LEDs with current limit resister, 8 pin SIP connecter, altho really just +12/GND if switched from elsewhere, like arduino with transistor driver.
no the LEDs will just be around the outside of the circle so something like a LED every 6mm as i will only be putting LED's around 270 degrees.
So SMD leds would fit.
So more like this?
What does the 110mm measure? radius? total length? diameter?
How will you 'point' them to avoid just blinding yourself?
If I may add, mellink, you may already know this but just in case you don't, SMDs are a PITA, using regular 3 or 5mm LEDs are a lot easier to deal with and you can solder them by hand without using a microscope. Soldering to flexible pcb, wow, that would be a challenge.
You can get really nice looking metal or plastic mounts that the LEDs slip into to make them look sharp and use predrilled hobby board and wire the LEDs by hand. Leave the leads long and you can form them into a perfect circle.
Or, if you want to go around the circumference, you can just use a piece of pipe, or the original dash, drill the holes to insert the mounts, add the LEDs and just wire them in place, no need for a pcb at all except for the driver chip.
for example :
http://www.jameco.com/Jameco/catalogs/c103/P30.pdf
yes like the design above but the LEDs would be pointing inwards so as to light the inside of the circle.
5mm LED's wont fit in the housing due to space restriction.
PITA? Sorry i google it and its just bread.
I appricate the advice. Its a confined space with no access from the outside of the circle so the LED's have to be inside the ring and flat. Hence why I though SMD (never used them before) but at the moment i'm trying so many different things so i figured why not, but mounting them in a good way will be hard. (it dosent ahve to look smart as the LED's are covered by a ring.
Thanks Again.
Merry Christmas.
PITA? Sorry i google it and its just bread.
Pain In The A**
Could you do something like this:
http://www.superbrightleds.com/pdfs/5050-CW6000.pdf
The LEDs are little flat squares with leads on opposite sides.
Make 2 rings of wire, tack on a couple of spacer wire to hold them parallel at the needed distance.
Take the 5mmx5mm SMD LEDs, solder one leg of resister across the Anode leads.
Solder the other leg to one wire.
Solder the Cathode leads to the other wire.
Remove the spacer wires.
End up with bunch of LEDs in parallel, all facing inwards to light your display.
Once working, glue a strip plastic along the outer back for insulation and to give a little more support.
Maybe start with just a few, may not need 30 x 6000mCD of brightness (that will be a lot!)
Think these are suitable?
im looking to get so many in there to mix colours and get a smooth lighting all the way around. I may PWM them to bring down the brightness
I don't see why not, is just an LED, yes?
Look at the size tho: 3.5 x 2.8 mm
That's 0.35 cm x 0.28cm. Giving yourself quite the assembly challenge!
Depending on how you wire them, for example in series as I had shown, you will need to output the PWM to a transistor and have the transistor do the turninf off & of of the LEDs.
I did a Charlie-plexed LED board using 5MM LEDs --
May be a bit bigger than you wanted. The schematic
and layout information are in the datasheet at
http://wiblocks.luciani.org/PICO/PICO1TR-LED-CL-index.html
(* jcl *)
I believe that would cover up the instrument he is trying to light up.
I have a solution for this but need to test it ill post it up when its done 
Waiting for my SMD to turn up Chirstmas holidays means my supplier isnt back to work until today!