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I'm building a computer, and I want to add LED lighting to the case.

However, here in Finland, LED strips are too expensive, and I found this: http://www.tinydeal.com/15w-360lm-6000k-60cm-12v-flexible-led-strip-lamp---green-light-p-107477.html

It's cheap, and it would be excellent for me, but I'm not sure if it's possible to cut it into smaller pieces. It's waterproof, so it has a silicone coating, but that can be peeled off.

Does it have soldering points? I'd rather not order a 5M strip, if I didn't have to. Or if I have to, can I cut this into smaller pieces? http://www.tinydeal.com/dc-12v-24w-300-x-3528-smd-blue-led-flexible-strip-lamp-p-93945.html

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  • \$\begingroup\$ Just to note, you can probably find LED strips pretty cheaply in Finland too, if you know where to buy them. Off the top of my head, Bebek seems to be selling some for 10€ / m. They're a hobbyist retail shop, so probably not the cheapest, but they have a store close to downtown Helsinki and will sell stuff in small quantities. \$\endgroup\$ – Ilmari Karonen Nov 19 '13 at 12:57
  • \$\begingroup\$ That said, the strip you linked to certainly looks like you could probably cut in up into segments if you know a little bit about what you're doing, even if it doesn't come with convenient "cut here" lines. Given that they're so cheap, you could just buy a couple and try it -- even if you fry or miscut a few pieces, you haven't really lost much. \$\endgroup\$ – Ilmari Karonen Nov 19 '13 at 13:03
  • \$\begingroup\$ @IlmariKaronen 10e/m is still pretty much compared to 5e/5m but I'll take a look! \$\endgroup\$ – user32949 Nov 19 '13 at 14:14
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What you want is a strip that has clearly-delineated connections between segments such as those that the LED strips that Sparkfun sells has. This way you can be sure that the segments are individually usable.

Solid strip (Sparkfun product 12021): enter image description here

Strip with individually-addressable LEDs (Sparkfun product 12027): enter image description here

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  • \$\begingroup\$ Problem with sparkfun and probably any store in US, is that shipping costs and taxes when it arrives to finland, makes it cost even more than in finland. \$\endgroup\$ – user32949 Nov 19 '13 at 14:25
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    \$\begingroup\$ @Christian: To be fair, I never actually suggested that you get it from Sparkfun, just that you get strips similar to what they sell. \$\endgroup\$ – Ignacio Vazquez-Abrams Nov 19 '13 at 14:39
  • \$\begingroup\$ I haven't been able to found any, with a reasonable price. All I've found is 5M/50€. \$\endgroup\$ – user32949 Nov 19 '13 at 15:41
  • \$\begingroup\$ @Christian: You just need to look around a bit. \$\endgroup\$ – Ignacio Vazquez-Abrams Nov 19 '13 at 15:52
  • \$\begingroup\$ Oh, I've been avoiding ebay as I hate the way it shows me result that won't ship to finland, but maybe I'll make an exception this time ;) Thanks! \$\endgroup\$ – user32949 Nov 19 '13 at 16:34
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While the picture isn't the greatest, both of those can be cut into three led segments.

It's easy to tell on the 5m one. The contacts are easy to see, at every resistor.

enter image description here

The green strip is harder to tell because the FPC is close in color, but the segments are made of two leds, the resistor, and the third led.

enter image description here

These basic led strips are simple. They typically have multiple segments in parallel, where each segment is 3 leds and a single resistor chosen for ((12v - (3* LED Vf)) / ~20mA. If you don't see a cut line, you can make an educated guess and measure the voltage at any given point. You should see 12v at the start of a segment, ~2v to 3v less at each additional point in the segment. Remember, Resistor location does not matter.

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ I wish I'd understand something about the circuit. But I could cut both of these, and they would still work? I already ordered some with clear cut marks from ebay, but it's good to know for the future. I just don't have a voltage meter. \$\endgroup\$ – user32949 Nov 20 '13 at 12:13

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