Thanks all for the help. Much appreciated!

I didn't think about copper being at the edges of the board so thanks for pointing that out

Thanks MarkT that is perfect.

One other thing I have just noticed is that the connections between pins and the ground planes (not connections that I have routed)have somehow ended up extremely thin - I'm not sure what I have done. If I open another board file the traces it creates are much bigger?

Thanks

(see top right of attached image)

Hi all, I have a quick question. When I create a gnd plane in eagle, I can't get anywhere near the dimension layer. I'm not sure what is causing this because it does it even with the polygon spacing set to 0? I would like to be able to get the gnd plane close to the edge of the board?

Thanks!

looks very cool! thanks for sharing!

Very nice! Good job there!

What is the purpose of the diode D1?

So you put 12 / 24v on the VCC pin of the WS2801 and use a resistor to drop to 5v? How did you calculate the value?

Sorry for the basic questions!

Edit - just looked through the datasheet again and noticed the section on powering from higher voltages. What is the diode that you used? Thanks

Before you start to test, the best bet is drop a line to gel manufacturer to ask LED-curable gels specification ( how many watts, wavelength, and time to cure).

The wavelength on LED gel lights is much narrower than that of the UV/compact fluorescent lights. This ­narrow wavelength emits the right amount of the specific UV-A wavelength that’s needed to cure LED-curable gels, which is why LED-curable gels cure faster in LED lights than in UV/CFL gel lights.  As most UV gels require the use of 350 nm. to cure, most UV lamps emit a wavelength ranging from roughly 320 to 400 nm. But an LED manufacturer that uses an LED gel that is rated for 375 nm. will use bulbs that emit from only 370 to 380 nm. “LED” stands for “light emitting diode,” which refers to the type of bulb an LED gel lamp uses.

for my understanding UV/compact fluorescent lights use at this application is 40 watts, your 0.02*3=0.06W single UV diode ( even 100 of them, still only 6 W) might take too long to cure.

Nails Magazine

Thanks, that is some useful info I will have a test with a few LED's later an see if it seems to cure it

Thanks! That would be good to see

Make sure the ceramic capacitors you are using have Flexible terminations (instead of just the matte-tin termination.)

Same with SMD resistors I guess if you can get them? The termination comes off of ceramic resistors pretty damn easy lol.

To the OP, you can download a CAM file from Itead if you are using Eagle CAD, so all you need to do is load up the CAm file and it will generate the correct gerbers for you that they require. Not sure if you would need a different CAM file for flex PCB's but I doubt it?

thanks for all the responses guys - all noted. Safety (eyes) is not a major concern since I'm planning to make a lamp to cure UV active nail varnish for my other half so you won't be able to look directly at the diodes and I will also have a countdown timer for a minute or so. I went with the idea of using lots of 5mm LED's because I need a large coverage area - enough to shine evenly over a hand.

I'm still confused, If I drive with 20mA the forward voltage is only 2.84V, and with a constant voltage of 3.1v, the LED draws 35mA. So.. should I still only drive at 20mA? I really can't see any output whatsoever at 20mA I know its UV and I can't see the whole spectrum but looking at it reflected off white paper I don't see anything. Another test I have done is to use a camera to pick up the spectrum and I cant see anything until I hit >25mA.
 I will have to test with the nail varnish stuff and see if it will cure it.

I don't know it really doesn't seem to be outputting anything at 20mA and if none of the light is visable then I'm wasting my time

I did have one running for a few hours at 30mA so maybe that is safe?

I want to run them from 12v in strings of 3.

I see thanks! So I could just use a NPN looking at the datasheet. I wonder how these are driven http://www.adafruit.com/products/683#Description I'd like to see a schematic for them.

thanks for the help, when you say external switches what do you mean? I thought the WS2801 could drive 150Ma and I'm only thinking of 3 LED's max per channel so about 60mA?

I thought that too about the voltage at the pin after being dropped but I don't see resistors in other WS2801 circuits to drop the RED, surely you would still have about 3V on the red pin with a 5V supply?

Thanks again

Hi all.

I am building a simple UV LED lamp and 100 of these have just arrived http://www.ebay.co.uk/itm/230930659493 and I am testing them on my bench supply, but either I'm being totally stupid or the data on the ebay listing is not correct.

If I drive them with constant voltage (no current limit) at 3.1V one LED is drawing almost 40mA, then if I drive in constant current mode at 20mA I get no light output, I have to increase the limit to around 35mA+ to get any decent light output.

I'm confused and basically trying to select resistor values but not sure what I should be driving these at?

Hi all. I want to make up some RGB pixels using WS2801 drivers and 5050 RGB LED's. I would like to use 2, maybe 3 5050 LED's on each pixel - I think the WS2801's can drive up to 150mA?

I'm confused about setting the output current. From my calculations from the formula on the datasheet http://www.adafruit.com/datasheets/WS2801.pdf, if I used a 15R resistor, then I should get a drive current of 40mA from the WS2801 - does this sound right?

Then the datasheet says

the voltage on R/G/BOUT should be set between 1 to 1.5 V

I'm not sure what that means? Would I not just connect the LED's to 5V and the WS2801 would sink the set current only?

Thanks!

Thanks for sharing! Looks cool, I will certainly be looking into this when I have finished some other projects