Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Ultraviolet light source UV-80 for PCB exposure

One of more advanced PCB manufacturing methods is exposing laminate copper boards covered by photo resistive layer through mask. Using UV light in manufacturing PCB’s has many benefits according to other methods: you can get thin tracks like 0.2mm. You couldn’t do this by using other home techniques like laser printers or hand artwork; other advantage is that this method gives clean image – smooth edges of PCB tracks. Little bit effort and you can compare results to commercial products. And pf course third benefit is speed and multiple replications of your boards by using the same mask. In this article is described the manufacturing of an automatic ultraviolet light source exposure box.


Parts for UV box

Case with organic glass
UV lamps ballasts and starters





Case is made of 5mm wood board wired with screws.





Making a control panel

Control panel consists of two parts:”Power control” and “Automatic control”
POWER switch is used to turn on/off power of the UV box. Green LED indicates the ON. MANUAL/AUTOMATIC switch is used to power l the UV lamps manually or automatically. Switches UPSIDE and UNDERSIDE are used to enable upper and lower lamps separately – in case you are using single or double sided boards.


When automatic mode is selected, then by pressing buttons MIN UP, MIN DOWN, SEC UP, SEC DOWN exposure time is selected. START starts timer counter and powers the lamps through relays. STOP/CLEAR is not implemented yet. LCD displays the Time of exposure, and after start is pressed it shows remaining time of UV exposure.




UV Lamps


There are used 8 PHILIPS TL 20W/52 lamps in this exposure box on each side. Some technical characteristics:

Wavelength, nm 450
Power, W 20
Voltage, V 57
Current, A 0,37
Cap G13
A, mm 589,8
B, mm 596,9
C, mm 604
D, mm 38



All view of lamps installed.




To make all the float of light towards the PCB there is Aluminum foil used. It also makes illuminations smoother.





The intensity smoothness viewed on white paper sheet at distance 5 cm from lamps.




The UV box is controlled by 8 bit microcontroller AT90s2313 from ATMEL. Circuit diagram is shown bellow:


Control circuit is very simple. Buttons are connected directly to I/O pins through internal Pull-Up resistors. When button is pressed – the “0” level in port input is generated, which triggers an action.
Buttons MIN UP, MIN DOWN, SEC UP, SEC DOWN are used to select UV exposure Time. START is for starting Exposure and count down. LCD displays time remaining.
There is standard HD44780U LCD 6×2 characters used. Lamps are controlled through 5V relays.
There you can see some Pictures of PCB.




Lamp control and power source

UV lamps are connected in series of 2 and then ballasts are connected. Starter is connected to lamps in parallel. Upper and lower covers of box can be controlled separately by using switch. In this circuit you can also see power control for microcontroller and relays.


Putting it all together





First test



Other examples you can see in my ARM section.

Download source code: Source Code




  1. You can find source code link at the bottom of my article. Here is direct link :


  2. André Dias Mesquita

    Which program to compile asm file into hex file are you using?
    Im using BASCOM but the program detect a syntax error. Error in line 1781 and 1782 and its impossible to continue with compilation. Could you send me the compiled file? Or help me how to solve this problem. I need to program the AT90S2313 to finish UVBOX.

  3. Hex file is already in archive. Download it and burn.

    Program is written in C language. This one is written by using Codevision C compiler. You can download demo from http://www.hpinfotech.ro/. It will be enough for this program. Bascom is Basic language compiler, which is not the same as C.

  4. André Dias Mesquita

    Do you know any DIY programmer to use with Codevision ? I built a programmer to burn AT90s2313 from Elektor 2003 July/August edition and it works with BASCOM and Sample Electronics Programmer and try to burn through hex file and nothing happenned using LPT port. 🙁
    All parts of UVBOX are ready except the main (lol). I need to burn this chip. What about PonyProg? Do you know any easy to build with minimal parts circuit that works with PonyProg??

  5. To make programmer for Codevision it would bu tricky one I think. You can find my DIY programmer for LPT working with PonyProg in this site: AVR ISP This requires only few parts and works like a baby for me.

  6. André Dias Mesquita

    Finally I programmed the AT90S2313 and tested the circuit but nothing happens, only one line from 16×2 LCD appears but without none character. Please Could you verify my board and my conections if I send you photos? I used ICPROG v.105 and the programmer from this page

  7. André Dias Mesquita

    Its working perfectly now I need translate to english some words that appears on the LCD screen. I just correct the connections that was wrong on the LCD and work fine. What’s language in that??
    Could you tell me the meaning in english of those words?

  8. Good to hear that 😉

  9. Hi, this is a great project for a (not so) starter like me but the schematics are so tiny that can’t be readed, can you post larger ones?

  10. Just press right mouse button and select “Save Image As” – then you download bigger images. Sorry for this inconvenience.

  11. can u send me via e-mail the hex file but in english version, because i don’t understand with the language that appear on lcd. thanks…. or u can tell me what language it’s.

  12. Source code have been translated to English language. Feel free to download it here:

  13. Pingback: Electronics-Lab.com Blog » Blog Archive » Ultraviolet light source UV-80 for PCB exposure

  14. The Source code link is dead…
    Can anybody email me this archive please?

  15. Repaired source code link. Thank you for letting know this.

  16. This is a great website.

    I’ve been trying to edit the source code with the CodeVision program but keep getting a file to big for evaluation version error, so I try the unedited (original) source code and get the same error, is there something I’m doing wrong?

    Also is it possible to get a higher quality photo of the light wiring as I’m finding it hard to read all the text on it.


  17. Now this image works as a link. Click on it to see bigger image.
    Well there may be a problem with compilation of source. Program was written for early version of CodeVision. Best solution would be to use full version or adapt source for different compiler like WinAVR.

  18. Pingback: Easy to follow guide on making PCB by using photo etching method - Scientific, embedded, biomedical, electronics contents.

  19. Hello
    I’m having a hard time finding the UV lights…
    I found one also from Philips: TL 15W/10…
    Do you think that it works also with this one?


  20. Of course they will. As they are less powerful, you’ll just have to increase exposure time.

  21. o.k
    Very good project congratulation.
    I have design a pcb on Eagle format

  22. what can, if uv lamp replace with normal lamp for use pcb exposure.

  23. Congratulations!!!!!Excellent project!!
    I build it and worked great.
    Hope that there will be another firmware release with the STOP button working.

    Thanks again.

    PS:You can use as an alternative, SYLVANIA F15W/BL350 UV lamps.Chipper and easier to find

  24. ?????? ???????? ???? ???? ??? ??????


  26. Hello. I’m from Iran
    Subjects did well in here.
    But I do not speak much English, and did not fully understand what you wrote!
    If you are sure this blog software, put the paper Tmaly Shmarv several languages, including Farsi () returned.
    Batshkr of useful information in here that did.

  27. I was made from this site uv box http://www.qubbeks.puslapiai.lt/readarticle.php?article_id=25 but it dont using UV LEDs. Exposing time are about only 6min.

  28. Dear..
    is different between neon usualy for room with for UV?


  29. Hi.
    Can you help me to make the stop/clear button work?

  30. Hi, i am unsure on what qualities the UV bulbs need to be effective at PCB exposure, would sterilisation bulbs work? This is an example of one i would likely be using if they are: http://www.swallowaquatics.co.uk/43/products/16_Watt_UV_Light_Bulb_T5_288mm.aspx


  31. Where do you get or how do you make the mask?

  32. Waht kind of glass u used it and thickness of glass and what is separation distance between glass and a bulb

  33. The glass there is Plexiglas (organic), as regular glass filter out UV light. The distance between bulbs and glass is ~8cm. The distance is not that big deal. More important to get even light on PCB.

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