Comments on: Making of the UV Oven

By: admin

admin — Tue, 22 Dec 2009 09:30:16 +0000

It does not really matter how bright the leds are since you will have to make some tests on how much exposure time is needed to produce the desired outcome.
I did that by exposing a photosensitive board while covering a part.. so I had tests from 30 seconds to 12 minutes.

From what I recall though , the LEDs I used were 35mcd. I just saw some leds on ebay that are 90-120mcd so your exposure times may vary.

By: oifex

oifex — Tue, 22 Dec 2009 03:17:46 +0000

Hi
Nice project. I’m thinking of creating my own UV oven. Unfortunately I can’t find any information about how bright the LEDs you used are. Can you give additonal information about how much mcd the LEDs should have at least?

By: Aris

Aris — Thu, 08 Oct 2009 10:38:05 +0000

Hi Stendall,

The current and voltage going through the leds is exactly as calculated in the excel sheet.

(and no led has been fried up to now)

Thing is that I need to put the sheet back online because it seems it is lost from rapidshare. I will seek another way to have files to download because I have no personal hosting.

Any Ideas?

By: Stendall

Stendall — Fri, 25 Sep 2009 14:16:04 +0000

You are goin to fry your leds.
Always, always, always there are tolerances.
It's not a good idea to put them in serial.

By: Aris

Aris — Sat, 25 Oct 2008 21:35:00 +0000

I got the leds of e-bay (50 leds for $10) and a perfboard from the local electronics shop for 3 euros ($4 but you can find cheaper on ebay). The transformer was salvaged from electronics recycling so it was free for me. I used a simple SPDT switch (add $1 at most but you can do without the switch). You might also need one resistor of high Wattage (2W resistor, no more than $0.30) and ribbon scraps or something to use as a hinge. so, it wouldn’t cost more than $20 at most.

By: john

john — Sat, 25 Oct 2008 17:12:00 +0000

About how much time did this take you and about how much money would it cost (ignoring the cabinet) if I had to buy everything?

By: Anonymous

Anonymous — Fri, 24 Oct 2008 10:18:00 +0000

RE: testing transformer with a tongue
power being 37watts (A times V), and assuming you are tranfering that every second it makes 37 joules. According to google 50 joules are lethal. Conclusion: testing that with your tonghe won’t kill, but you would certainly feel the pinch

By: Aris

Aris — Fri, 24 Oct 2008 07:43:00 +0000

There was only one time I ever wanted to make a double sided board and this was for the timer I designed for the UV Box. I just turned it over after 15 minutes

The thing is that these leds have a beam angle of 25 degrees so if the board gets too close to the leds, there will be circular spots where the exposure is greater. It might ruin your board this way.

Nevertheless, in a more demanding environment, your idea would be very time saving. It just cuts the exposure time in half.

By: Anonymous

Anonymous — Fri, 24 Oct 2008 07:17:00 +0000

Why not using another array of leds on the bottom of the cabinet? If you use a transparent pcb holder (maybe metacrilate of some other transparent plastic) you can get double sided boards!

By: Aris

Aris — Fri, 24 Oct 2008 06:32:00 +0000

There is a parallel line of strings of serially placed leds. Which is actually this.. I connected 7 leds serially and did that 5 times. These strings are connected in parallel.

I did some small calculations based on the voltage drop of each led and the current I wanted each led to have so if you go to my files, there is an *.ods file (Open document spreadsheet, opens with openoffice) where you can put your values for the leds and transformer in your setup and it spits out the resistor you need to place so as not to burn the leds or not get light at all.

If you have any questions, please drop me a comment. !!!