The return of the dead flatbed scanner

How a dead scanner can return as a printed circuit board UV lamp. Keep that cover closed !

Step 1 Forewords

I made this Ultra Violet bed to make printed circuit boards a few years ago without Instructables.com in mind, so rather than a step by step pictorial description of how I made it, I'll provide you with a few pictures of the finished work and hints on how you can do the same. Hope this will help anyways.

First of all, safety. Notice that this is a mains powered device so maximum care must be taken in the design to insure that for no reason someone may come into contact with live parts. If you are not sure about medium voltage (mains) electrical wiring practice ask a friend or someone else whom is.

Comments

[mrgibby]

good diagram, although where i come from green tends to mean ground, so i might've chosen a diff. color for circuit wiring. Otherwise though nice layout. Yes by all means ground every metal part that's not part of the conducting circuit.

[5Volt]

Yes, absolutely true. I actually remember seeing in South Africa a wired panel with green ground wires....I made an unfortunate choice of colour indeed ! Thanks for pointing that out. Ciao 5Volt

[spylock]

Are these the same lights that will kill algee in fish ponds?

[Foxtrot70]

Hi 5Volt, the all green wires remind me of a past employer of mine. In an attempt to "Spend a Penny to save a Pound" one of the geniuses in engineering sold the idea of changing color coded wire loom to all white with (you won't believe it) the connection info printed on both ends of the wire. One needed a magnifying glass to read this stuff 24 ga. wire makes for a very small type point regardless of font! The result of the 3 year exercise was "A Pound was spent including the Penny"! ARGH, management what would we do without them.

[hamstanz]

i'm also quite confused as to which type of UV light i should be using. I take it that this is a Black light one, although i see this person (http://www.instructables.com/id/Pro-lichtbak-voor-weinig-geld-Pro-UV-lightbox-fo/step7/Eind-kosten-final-cost/) using tanning Bulbs. Which one will expose a board the fastest ? Which one is most suited to this application ? Thanks a lot in advance

[hamstanz]

Was wondering if you could tell me the exposure times for this setup and the exact model of the bulbs thanks

[12V]

why not fit a cutout switch(so lamps extinguish when cover is opened).

[jimwig]

labtech you did think of it. sometimes you just feel as if you were there when the project became reality. eh? ideas float in the air and when someone moves on making one we all benefit or not. a connectiveness of sorts.

[jimwig]

in the usa

green is ground
white or gray is neutral
black is hot leg or #1 in multiphase
red is " " #2 " " "
blue is #3 in 120?208 multiphase
orange is # in multiphase or a high leg in a Delta
brown is # in

hey its been so long that my brain is in the wrong phase. sorry look it up and be careful.

remember that if you are not grounded shock potential is minimized or eliminated BUT trickle currents can still shock the doggy doo out of you.

stand on a dry insulator if you MUST work on a live mains situation

try not to do work without another person close by

try to learn to give CPR as coronary arrest usually occurs in electrocution

And generally if in doubt DON'T $#% with live circuits.

BE CAREFUL and BE RESPECTFUL and be SAFE

[labtech1952]

Great project. The only criticism I have is; Why didn't I think of this?

[DillyDog]

This would be really cool by using a scanner with a transparency hood and having UV tubes in the hood as well. That way, you could expose 2-sided boards without the risk of accidental movement when turning the bord over to expose the second side. All the the ballasts and starters could be housed in the lower casing, while just having the tubes in the hood. I think I'll get that old scanner out of the attic and have a go! Thanks for the idea, it had never occurred to me before.

[dpocius]

Or, if you had 2 identical scanners, you could take the covers off both and hinge them together, face-to-face (with UV tubes in both, of course.) Also, add an interlock switch to kill the UV when the cover is opened. Also, get a spring wound timer switch like on a bathroom heat lamp to set a repeatable exposure time.

[txtsttoo]

nice idea, yea. Can someone tell me if i can do this,in an non working scanner ? by using bulb's or floureocent tubes' if there is someone who likes to help, e- mail me : [e-mail] thanks to you all Buddies. jerry.

[5Volt]

Of course you can do this thing to a working scanner. Using a non-working one is more cost effective though. Read the full instructable and learn how. Click on "view all steps on one page". Ciao

[5Volt]

Thank you everybody for the interest shown. I didn't think to an instructable on how to actually make PCBs, Sumguysr summarized well and Googl-ing gives excellent results. Yes, I read that visible, strong light gives results with PCBs as well. Makes sense as many common light sources do emit in the UV as well. EEPROMS are hard to find, better luck with EEPROM-based microcontrollers. Not sure about the wavelength required by EEPROMs but I think that these should be erased just fine, didn't try, though. OSKAY, UVs are reeaaally cool ! But nobody should indulge in staring UVs, the damage is the one you do not notice until late. After a few seconds your eyes start sending painful signals. Interesting experiments include (wearing wide sunglasses) looking at crystals and common stones, invisible dust and stains, fingerprints and, well, everything. You'll see a lot of new things. It's like listening to ultrasounds (?) or listening to Infrared sources (??). Well, on this, sooner or later. For now, just Google around. How about replacing the visible tube of a battery operated portable camping light with a UV tube ? Not good for PCBs but great for looking at things in a much different way. Ciao e a presto 5V.

[Coolbreaze]

BTW you are confusing EEPROMS with EPROMS. You don't erase EEPROMS with UV Electronically Erasable Programmable Read-Only Memory You erase EPROMS with UV erasable programmable read-only memory For optimum erasure time UV light must have a wavelength of 235nm But I'm still 95% sure your box would erase EPROMS since you can leave em outside in the sun to erase em....just takes way more time!

[5Volt]

Not confusing, just mistyping and not reading again! actually EEPROM-based microcontrollers would be slow as a dog ! Ciao 5Volt

[Coolbreaze]

Very nice way of recycling an old scanner for photo resist etching purposes!
You could also use it to erase eproms =)

2 1/2 thumbs up! (where does the half come from? nobody knows!)

[sumguysr]

im afraid it wouldn't work to erase eproms. eproms require near band ultraviolet light, which will not work for exposing photo resist. Who cares though, uv erasible eproms are ancient.

[Coolbreaze]

I'm like 95% sure it would work since you can erase eproms using the sun light!...leave your eproms outside in the sun for 3 days and they are erased...so why wouldn't UV lights do the trick over a long period of time? Yes wouldn't be 15minutes like a normal UV eraser but still!

[radikaldesig]

It is a very good idea.
That wavelength has the light of the tubes?
Thanks
radiakldesig.comradiakldesig.com

[5Volt]

Thank you. I used no brand tubes. Philips common TL5 8W tubes emit in the range 280 - 400 nm Ciao

[T3h_Muffinator]

It seems cool, but I'm not exactly sure how it works. Is there some kind of mask that you put on the board and then gets eaten away when exposed to UV?

[5Volt]

Last minute: makezine links to a number of instructable.com instructables and more on how to make PCBs.
Thanks to Phillip Torrone (of Makezine).
Ciao e apresto 5Volt

[sumguysr]

the photomask process for creating pcbs is basicaly as follows 1. you design a pcb on a computer 2. you print out a film of the pcb, usualy on a transparency or better yet on tracing paper 3. you coat a copper clad board with photoresist using a sprayer or a laminator and resist film, you can also buy pre-coated boards 4. you use the film to mask the board and expose it to UV light 5. you place the board in developer 6. you place the board in etchant, usualy ferric chloride, amonium persulphate, or cupric chloride.

[ksjlkdjlddj]

I bought a second hand face tanner at a flee market for 2€, and use it to expose my PCB's. It works just great and is dirt cheap! It has 4 UV-A tubes with their starters and ballasts, and even a crude timer (which I don't use). From my experience, it would indeed be better to have the UV light move around, this would eliminate shadowing at the edges of traces. I avoid this by moving the face tanner a bit after half of the exposure time. Make sure your artwork does not move in respect to the PCB you are exposing though. Summary: the cheapest source for UV-A tubes are second hand face tanners. www.steeman.be

[5Volt]

It's incredible the number of free or cheap things that can be reused or recycled. Thanks, good hints. 5V.

[oskay]

Brilliant!!!

By the way, I've had excellent luck exposing PCBs with regular fluorescent lamps-- so I don't think that you *need* to use the UV bulbs. (Although they do look *seriously* cool.) Do they significantly cut down on the exposure time that you need? I remember using about seven minutes per side with regular fluorescent bulbs.

[chaydgb]

Cool idea, nice job! Shame I've recently chucked a scanner, and I just happen to be looking for a photoresist exposure box too :(

[Sergiozal]

I did almost the same with ordinary daylight lamps - six 20W bulbs - to use it as a light table to view negatives. Works quite nice.