I went with SMT (Surface Mount Technology) LEDs, it made my life much simpler in several ways.
1) they were cheaper than the same ‘conventional’ LED
2) They have no leads, so you don’t have to worry about drilling holes in a PC board or using a breadboard.
3) they are drastically thinner, so they take up less space at the edge of your display and the whole
mess is easier to mount.

NOT because I believe I made the ‘absolute best’ choices, but to answer in advance those who will ask, I used these: http://www.mouser.com/Search/ProductDetail.aspx?R=OP200virtualkey54210000virtualkey828-OP200
They are 880mn, which was well below the transmissive cutoff of my acrylic, also they were only 26cents each
when I was buying 150 of em. I arrayed them in series groups of 5 with a 330 ohm resister at the head of each
series group, strung the groups in one big parallel, and hit it with a 12V 1A wallwart...they are BRIGHT, and
with 75 LEDS in a 24"line down each short edge of my screen, they sure seem to do the job, so far no failures.
Then I lucked into an 875mn bandpass filter dirt cheap that was the last piece of overstock a nice man who makes
high end filters had laying around.

Here’s a a couple of pictures of my own table’s wiring method, and my first boards after etching, and the finished rails with the IR filter intact on the camera that if taking the pix, (they are MUCH brighter in person):

You will need:
1) laser printer, OR a copy shop (I used PIP) where you can make laser copies...inkjet will NOT work!
2) heavyweight glossy photo paper (again, PIP)
3) an Iron...an ordinary clothes iron
4) tub of water (I used the bathtub)
5) blank PC board (any electronics shop, even radio shack)
6) etching solution (again, even radio shack)
7) a ziplock freezer baggie
8) acetone (nail polish remover)
9) some very fine sandpaper (600 grit or finer), steel wool, or a green scratchie

Radio shack even sells a basic kit for around $20 that contains a small blank PC board, some etch solution, a
sharpie, and a chunk of green scratchie. It may be all you need, and you can just follow their instructions for
mediocre results that work, regardless it’s a viable choice for etching solution if you can’t find it elsewhere.
My method does a MUCH better job of giving you a cleanly etched PC board (that no one will ever see if nothing
fries in public).

I bought it all...including a replacement for the Mrs’ cheapo iron for a total of $40, made the PC boards I
needed and a spare set.
If you want you can draw your design with any graphics program, for those who are insecure, there is a free
circuit board design program available at:  http://www.expresspcb.com
It even includes ‘templates’ for various components so you can leave the correct space between things.

1) Draw your circuit board on your computer, life size, save it as a .PDF or a .PSD (if you use that program
above, ‘print’ it to a file using the PDF driver). if you are going to PIP you may be able to email it to them
to print for you. You may also print it out with inkjet & have someone laser copy that, but your contrast will
not be as great as if it is printed from a file.
2) Have it laser printed as DARK as you can onto heavyweight GLOSSY photo paper, laser copied is the same for
our purposes. You want your white parts to stay white, but you want as much toner as you can get on the black
parts. (I made two copies & was glad as it allowed me to screw up the first try of the next step without having to
go back to PIP)
3) LIGHTLY sand/steel wool/green scratchie your PC board to clean the oxidization off of it, don’t get carried
away, you need to leave the copper then wash it with acetone or alcohol to remove any grease.
4) Place your laser copy of the design on your PC board, printed side against the copper. Iron it on to the PC
board. Use the highest setting. Don’t forget to use some cardboard or something to protect your floor or table.
And don’t be gentle, you will want to smash down quite hard while you iron it so you get pressure as well as
heat (I was a wimp on the smashing the first time, it took forever to get a bad adhesion, try#2 I got medieval
on it and it adhered in abt 3 minutes VERY well, but I did put a couple of scratches on the iron...the MRS
was not pleased...probably some middle ground available somewhere).
5) Toss it in a tub of hot water. Let it soak for abt 5 minutes & then begin rubbing on the paper. Glossy photo
paper has a clay surface that gives it the gloss. As the paper softens, you can rub it right off of the clay.
The clay that is not mixed with toner will also rub off. The toner has been heat fused to the copper, and will
be rather difficult to remove. I was able to remove the last of my clay/paper debris by lightly cleaning it
with a ‘green scratchie’.
6) Dry off your design, and if it needs any touch-up use a sharpie marker. Sharpies DO resist etching solution,
but not really well, so if there are big problems, you may wish to redo the transfer.
7) Traditionally you put etching solution and the board in a rubber or porcelin tray, and then must be concerned
about how to agitate it to release bubbles, and lifting it to tell when it’s done without making a big acidic,
staining mess...but I don’t play that way. Instead put your PC board in the ziplock freezer baggie, pour in
the etching solution, zip it shut, and toss it back into the warm water to allow heat to speed up the etching
process (also containing it in case your baggie leaks). Now you can agitate it by smooshing the baggie with
your fingers (still underwater, safety first), and check it the same way without removing it.
8) When it is sufficiently etched, unzip the baggie, remove the PC board and toss it back in the water to get
the etching solution off of it. If you plucked it out with your fingers (me), wash them you moron. Zip the
baggie back up & dispose of it, or pour it back into the original container to reuse or dispose of (careful
about pouring or you’ll have that mess we avoided previously). You can reuse etching solution more than once,
but it does eventaully saturate & stop etching...do NOT store it in the baggie as it will leak when you aren’t
watching & the Mrs will shoot you in the face
9) Clean the toner off of the PC board with acetone (and a green scratchie if you’re impatient like me)
10) Drill holes for lead wires if you need to. Trim the boards if you need to. Solder & enjoy.

Update: I discovered I was using the wrong resister value as these LEDS were more robust than I had thought...and subsequently was robbing this already bright set-up of almost half of it’s available output...then for good measure in my quest for ‘sunlight resistance’ I doubled up on the leds as well...too much is never enough eh? Blobs are freakin phenomenal, but as anyone who read the updates in my mirror modeling post knows this build is not ‘road ready’ due to material choices and MKll is scheduled to happen this spring.

Great Post Trackzilla… I’ve however found out if you are getting etching PCB’s one key thing to note is that Colour Laser Jet Printer Ink doesn’t work for Toner Transfer method, you’ve described, the toner never fully transfer over if it does during the etching process it also gets easily dissolved cause breakages in traces. Also better than Photo/Glossy Paper are transparency films, any decent photocopy store has them, I goto Staples here in Canada. And the remarkable thing is that they don’t melt under the heat of the iron since they are heat treated for laser printers.

1.You pretty much design your circuit in a freeware program such as ExpressPCB or paint as i have.
2.Print it out on transparency film.
3.Align your copper clad board (PCB) and transparency film), and tape the edges using a little tape, as safety measure place a blank sheet of paper on top.
4.Heat the iron to its highest setting, and place it on the paper (and DO NOT move it for 5-10sec) , you will notice that the transparency will shrink slightly don’t worry.
5.Iron the entire transparency, It should take around 3min for the copper to heat up completely and another 2min for the toner to fully transfer over to the copper. (its a good idea on the side of the transparency to have small test image printed as to see if the toner has fully transfered.
6.When the toner has fully transfered, dunk the entire thing including the stuck transparency in cold water and let it cool it should a minute or so. After which the transparency will easily peel off without any scrubbing of the PCB, leaving behind your circuit.
7.Next etch your PCB i prefer Ferric Chloride, since its less dangerous to use at home.
8.After etching you can either use Acetone to remove the toner or burn the toner using a lighter, If burning the toner NOTE: DON’T apply heat for too long as it may cause the Copper to peel off.

Below are 2 PCB layout i created for 112, OSRAM SHF485 IR emitters, you need 14 Arrays such as this. I used 8 IR emitters and one 1ohm resistor in each of my series configuration.

Hope its useful to people. and G’Luck

Taha

***UPDATE***
If for some reason you have an area where the toner hasn’t fully transfered over a small area you can use a black permanent marker to draw the trace in before etching your circuit.

Excellent addition, thanks, I didn’t even think about transparency film...I know how I’ll do my next one now! And the test image is a good idea as well.

I did mention about inkjets not working, but it’s good to stress that again, inkjet ink will NOT work, it MUST be laser printer toner!

Yes, I prefer Ferric Chloride as well, it will still stain things like a beast...but it doesn’t immediately eat a hole in your bathroom floor when you ‘oops’

Hey Trackzilla,

Loved your detailed led instructions series.
Do you have any pictures or results with the SMT LEDs ?

Thx in advance !

Thanks!
All I have currently is the very first image of raw IR blobs from the cam on the mockup, it is not at all representative of the tested results, sort of like seeing baby pictures of your favorite actress, lol.
After succesful testing the cardboard mockup of the box was sort collapsed under it’s own weight, it WAS just intended to allow me to check my IR amount & my mirror positioning anyway. The final build of the box I designed is going nicely, though slowly...since I have to find time between work schedule, have to build outdoors due to space & mess, and am doing the whole build with hand tools...I hope for final assembly by early next week, pix will follow promptly.

This is actually a quite good idea. Must be much easier to install.

So, did you get black fingers like I once did with silver nitrate?

Here is a great site for simple etching.  I’ve had very good luck with Staples photo gloss paper.  Also instead of etching solution you can use hydrogen peroxide and muriatic acid (available at most hardware stores)

If anyone in Nuigroup need to get custom circuit boards or PCBs made, let me know.  I have a cnc router that can be used to make a pcb.  I just bought the machine so i’d like to practice.  All you need to pay for is the material and shipping.

Hi, we have a couple hundred pcb stripes here and are selling them for 9$ each without leds of course and for 10x 70$ + shipping.

Each stripe is 12 inch long and holds 24 1206 smd leds and res.
the leds are in groups of 3, so the pcb can be cut to length or extended unlimited

And this are professional pcbs, with silkscreen and solder stop mask.