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How to connect LED Strip to USB cable? Answered

I am currently making an Art assignment for my class. I am trying to crete art using light and I decided to use LED Strip instead of other lamp. I bought a 1 meter long for a prototype before installing the real one. I am cutting the LED for about 10 cm long. Now, how do I connect the rest of the LED to a USB cable? The LED Stripe comes with mod and controller, but I cannot purchase it separately. I dont want to buy another 1 meter long and only use 10 cm of it. How do I exactly connect this one to the USB? I tried to search the videos on youtube, but most of them are only having 2 area for plus and minus, but mine are having 4 area named R, G, B, and Com. I have no clue at all, so blind right now. I dont want to waste the rest 90 cm LED I dont use. If any of you know how to combine this, please help me!
thank you very much! 

4 Replies

ThirdEarthDesignBest Answer (author)2017-03-08

The R,G and B connections represent the LED colours Red, Green and Blue. For example, if you connect up the B pin, you'll get blue light. If you want white light, you need to connect up all three (red, green and blue makes white). By mixing different combinations of R,G and B you can create other colours. The control boxes that operate these strips use PWM to vary the intensity of each LED colour to mix a broader range of colours.

Do you know what voltage your selected strip is using? These are commonly supplied as 12v, though 5v strips are readily available (note that USB operates on 5v). You will struggle to get the strip to illuminate properly using USB if the strip is designed for 12v.

The only other question here is the polarity of the pins on the strip, sometimes the R,G,B are (+) positive and the COM is (-) negative, but I've seen plenty of strips where the R,G,B are (-) negative. It will only work the correct way, so if at first you don't succeed, try reversing the polarity.

If you are not familiar with USB wiring, I've included a USB connector pinout diagram. If you are stripping the USB cable, the positive will be red and the negative will be black.

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YosukeH (author)ThirdEarthDesign2017-03-08

Hi thank you very much for the answer! So far after reading the old posts, I believe my LED is 5v. I really have no idea where is the (+) and (-) but after you explained it, I have some clues now. thank you! I will try to do what you suggest and will switch the other way around if it is not working! I really have no experience with LED before but I really want to understand and learn this stuff, it is kinda interesting and fun now.

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Downunder35m (author)2017-03-08

We had the topic of LED strips and USB several times already, I suggest to look up some of the old topics as the answer won't change.
And unless you got a 5V LED strip it won't work on 5V anway.

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YosukeH (author)Downunder35m2017-03-08

I already look trough many old topics, but it seems none of them represent my problem. So I decided to make one. They are helpful, but I cannot comprehend it because I really new to this stuff. :(

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