Led set-up for UV exposure box.

On June 6, 2011, in Electronics, by Cmc

Making Led exposure box is basically an easy thing. But unless you wish to use high voltage tubes for PC exposing, you need to do some tedious work.

I decided to use 3.5V 2000mcd 3mm UV LED-s. There is area of 160×100 that needs to be covered. At first I decided to place the leds in to 1cm grid. Then I had some second thoughts if this gives enough light to get UV sensitive pcb boards to be ready for development solution.

So to be ready for adding extra leds I drilled many extra holes. This way I have same board ready for expansion. I can almost double the led count.

For meeting these requirements I had made it was necessary to drill around 310 holes in to the base board (which is 2mm colored plastics). After that came the really tedious part. Setting the led’s in place, bending the leads and soldering it all together.

As I need to power all of these led’s it was considered that I use 12V power supply. That is the reason for having these things grouped by three. Additionally there is need for few rectifier  diodes to get voltage correct. 2 x 0.7Volts dropping  should do it. (3.4×3 + 2×0.7 =~ 12V  i think that additional 0.2V will not harm the led’s because they are rated from 3.2V-3.6V.

And here are some pictures of the board:

The bending and soldering


Close up from what I did there


The board from the led side.

It is quite nice looking board. Now there is adding power and I can see how it gives me a tan and easier pcb-s!


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