Well you COULD design and print a repeated pattern that the leds and resistors could fit in. then cut etch the whole pattern at once. After that you could cut the completed and etched strips from the pattern. Buy you will want a lot of copper to help with heatsinking.

[ed]

Oh jeez. Youre in for a world of hurt. The SMD LEDs you got are under tabbed. They are usually used in an automated or paste deposit and reflow oven type soldering technique. You MIGHT be able to bend the tabs around to use them, or you may be able to solder them as is if yore good and have a REAL fine tipped soldering iron.

HT-T169NB-5538:

[/ed]

 

the only type ive seen and used are under tabbed what other types are there? In the prototypes ive made i glued them down and was able to solder to the sides of them pretty easily.

 

ok.. good. You have experience with these type? then your good to go. I was worried this was your first experience with them..

 

usmc96gt - are you in the States? BTW, what was your MOS?

It's a good idea to at least put your country/state in your profile (User CP link on top)

Soldering the LEDs to strips of PCB's would be much preferable to using just plain wire. It'll keep the LEDs a lot cooler.

[eta]

Just a concept - get some thin PCB material like I linked to previously.

When you get the stuff, put on rubber gloves (heavy-duty dishwashing gloves) and scrub the copper side really well with a 3M(tm) Scotchbrite(tm) pad (you can find them in grocery stores next to the sponges, etc.) and then wipe it down really well with acetone (nail polish remover) and white paper towels several times until the towels remain white.

Then apply some narrow tape (pinstripe tape would probably work OK, 1/20" to 1/8" wide) in parallel strips across the board about 1/2" apart. Be careful to not get finger oils on the board while you're doing this. If it's too awkward wearing the gloves. use something really clean to hold the board down with, and make sure you don't put fingerprints on it. Wash your hands with the old blue Dawn dishwashing soap (under a buck at the supermarket) - Dawn is great stuff for removing grease and oil.

Then spray the board with a light coat of lacquer. Let dry a few minutes. Spray it again, let dry another few minutes. Then pull the tape off. Let dry for an hour.

Etch the board using Radio Shack PCB Etchant (Ferric Chloride) - if yours doesn't carry it, you can make your own etching solution from hydrogen peroxide (a buck or so at any Big Box Mart; comes in a brown bottle) and muriatic acid aka pool acid; swimming pool supply stores or hardware stores, maybe $5/gallon.

If doing the hydrogen peroxide/muriatic acid, measure out 2 parts hydrogen peroxide and pour into a plastic container. The black plastic stuff like Stouffer's frozen entrees come in works good - don't use Tupperware or anything that is nylon or dacron. With your rubber gloves on, slowly mix in 1 part of the muriatic acid. Don't even open the muriatic acid unless you are outside. You don't want to breathe it at all. If I am mixing/using the stuff, the garage door is wide open and I have a big fan on full blast blowing the fumes away from me. Keep a bucket of water handy in case you spill/splash on yourself or other stuff you don't want messed up. Dilution is the way to go.

Put the board in the solution copper-side up.

If you're using the Radio Shack PCB etchant, just rock the board in the solution back and fourth for maybe 10-15 minutes until you see that the lines are etched through.

If you are using the peroxide/muriatic mix, use a paper towel to gently wipe all over the copper side of the board. This helps to speed up the etching process. The peroxide corrodes the copper, the acid eats it away. By wiping all over the copper, the corroded copper is removed much more quickly, and fresh etchant gets right back to work.

After the copper in the strips has been etched away, rinse the etchant off thoroughly. You can use the emergency bucket.

If you want to save the etchant, that's fine. It can be used again. Don't seal the bottle up tight though, because the chemical action will continue for a while, and a sealed-up plastic bottle will look more like a basketball if you wrench the cap down. Give it a day or two, then seal it up.

Use lacquer thinner or paint stripper to get the lacquer off. MEK works, but you don't want to breathe that stuff either.

After you're done with cleaning off the lacquer, cut the board into 1" strips lengthwise and 1/8" vertical strips using a paper cutting board. Remember, you can combine one resistor and one LED in one PCB per string, so leave two etched strips every 5th section.

 

Another thought, the pattern is simple enough a sharp knife and a soldering iron can remove unwanted copper. This isn't practical for complex board, but for simple stripes it is a snap.

I've done similar for similar projects.

 

Well, it might be problematic using a knife with really thin board material. It would be far too easy to cut right through it, and then that section of the board would be scrap. With standard thickness FR4 that's easy to do, but you can't cut standard FR4 easily with a paper cutter.

 

That isn't what I'm talking about. I've used a exacto blade and a metal straight edge on blank PCB stock, the soldering iron softens the glue holding the copper to the board. You cut a strip in the copper board, and it will peel right off, sometimes the soldering iron just gets it started and you can finish it off by simply peeling it.

Blades come in smaller sizes than swords Wook.

 

thanks for the input guys I ordered some of the cladding to see how it will work and the time involved in it. Sgtwookie, I almost have the dimmer made but I cant see to figure out how to wire the mosfet up. Ive searched and found the name and location of the legs but not how its hooked up in your diagram. btw i thought i did fill out the geo data but maybe not anyways im from west palm fl, and was a avionics tech on h53-d out in hawaii

 

You might be able to get the same brightness with less current by using Pulse Width Modulation (PWM). I would look at the LED drivers they have available, some have PWM capabilities. Although you might have to purchase several of them in order to get the number of LEDs you want.

Austin

 

thanks for the input guys I ordered some of the cladding to see how it will work and the time involved in it.

Cool deal.

Sgtwookie, I almost have the dimmer made but I cant see to figure out how to wire the mosfet up. Ive searched and found the name and location of the legs but not how its hooked up in your diagram.

OK, that's understandable.
I try to follow conventions when I draw up schematics.
Inputs from the left, outputs to the right.
More positive voltages towards the top, more negative towards the bottom.
That way the schematic reads like a book; left to right, top down.

The gate is the control input to the MOSFET. It's on the left.
The source terminal is grounded.
The drain is connected to the cathodes of all of the bottom LEDs.

Which MOSFET did you wind up getting? The one I used in the schematic will work just fine, but you could use quite a wide variety of MOSFETs in it's place.

btw i thought i did fill out the geo data but maybe not

If you filled it out late at night, it might've "gone away" when they shut the board down for maintenance. Occasionally, posts don't "take", but that's getting to be rare.

anyways im from west palm fl, and was a avionics tech on h53-d out in hawaii

Cool!
I wanted to be stationed in K-Bay for awhile, but didn't work out.

Had my first and only rides on USMCR CH-53's from NAS Memphis to Philadelphia PA; our all volunteer Drum & Bugle Corps (MATSG-90 Band) was asked to come up and play for the dedication of their Bicentennial Building. Those are big bad birds. Somewhere I have some really nice photos I took on that trip; darn if I know where though.

 

Have a look at the attached schematic.

It consists of the 24v power supply, an LM317 regulator to drop the 24v down to 12v, an LM555 timer, a power MOSFET and associated parts for PWM control of the LED's intensity.

I don't know how to get this to a new thread, so I need to ask this here sorry
Could I use this wiring of the 555 timer to drive a servo motor? They basically respond to PWM, correct? I want to control a servo motor but don't want to mess with buying all kinds of junk drivers.
I realize I will need to change the frequency of the PWM to something lower that the motor understands.

Thanks,
M

 

Don't hijack threads; it's considered very rude and makes extra work for the Moderators as well as confusing the thread.

The correct procedure would be to start a new thread with a subject like:
"Can I use this circuit for a servomotor control?"
and provide a link to the thread in question, and specifically the schematic in question.

But the answer is no, it will not work for a servo controller.
Lots of ideas here: http://www.discovercircuits.com/S/servo.htm