LED project questions
MakerNewbie wrote 05/20/2016 at 18:51 • 0 pointsI'm retrofitting an antique(?) desk lamp to LED. The original lamp used two 18" fluorescent bulbs. I didn't see anything that was a perfect drop-in replacement, so I plan to get some 2-foot LED strips and cut them to size and mount 4 of them. I would like something dimmable, and the idea of changable RGB appeals to me as well. Here are my questions:
1. Are there any issues with just cutting the LED strip at a desired length
2. If I decide to go with changeable color LED strips is there any difference between buying one big color controller and wiring the four strips in parallel, vs getting 4 cheapo controllers and hoping the control units are universal and would automatically affect all four of the mounted strips?
3. Since this is a homebrew solution; it looks like the strips run on 12v and that PSU doesn't come with the strips or controllers. Anything (other than amps, and a size that will fit inside the lamp's base) I should be considering when selecting a PSU?
Thank you!
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email me already done what you want
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great answers guys!!! So many forums people are rude to newbies. Thank you for taking care of MakerNewbie's question.
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1. If you look closely at these LED strips there are normally a few LEDs of each color in series with an additional drop resistor to limit the current, these "strings" are then repeatedly connected in parallel down the strip ("copy&pasted"), so there are specific spots that make sense to make cuts at (normally marked)
2. I don't know if I got your question right. If you wire the control input of the 4 small controllers in parallel (assuming it is a digital signal) it should work. If they use infrared as input they should not used individual encoding so one remote should affect all (cheaper to manufacture), but you never know. Your time/effort to get four of these to run is propably worth much more than the bit of extra money one big controller costs.
3. add 20% margin so the PSU does not run at 100% (during power-on the controllers might draw a current spike). Consider cooling and grounding (assuming a metal lamp enclosure)
Depending on what you plan to use the lamp on I suggest just go for warm-white single color (cheaper, easier, no "rainbow shadows").
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Hey MakerNewbe, clever use of an old lamp! No there's no problem cutting the LED strips they are made that way, people usually buy them in the bulk rolls. As far as a controller, certainly go for just 1 controller, no need to try and stuff something that may not fit anyway, here is a great website were you can find LED strip controllers that are RoHs certified; http://www.superbrightleds.com/cat/rgb-led-controllers/
This page brings you directly to were you want to begin your search.
Good luck!
Dave H
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