Purchased 2 units a months or so ago. As mentioned in other reviews, the connectors are reversed from every other light strip I own. This caused me to reverse polarity the power. I then cut off the connectors and resoldered, but I guess the damage was done. After buying 2 more last week, I carefully made new connections but still do not have any active lights. These seem like a good idea and appear suited to a project I would like to build, but currently I have spent over $85 plus tax for no result

My light strands seemed to be bad. I was using the female side (male pins) that connects to another strip of pins as the input. Was expecting that it didn't matter which side I used to test them. The male side (female pins) needs to be used for the connection to the MCU. The +5v pin is marked in BLUE with my strands on the male connector end. The female connector end is marked in red. I am able to put 2 strands together and they both work. The yellow tag that labels the wires is correct. In my opinion it is labeled on the wrong end as that is the end that connects to another strand, instead of the input end. Using the FastLED library with WS812 GRB configuration. Good luck!

These lights were exactly what I needed! I had been looking for small yet bright lights for a costume piece and these worked perfectly. I weaved them into a vest and though the rest of the electronics still require additional modifications, these lights did their job splendidly.

Made a "firefly jar" for my deck. All comments regarding which end to use are correct. The sticker comes on the wrong side... Otherwise, an ESP8266 and a level shifter and my fireflies are dancing to the command of my phone!!

I am working on an art project that will use fairie light strings. I bought one of the Sparkfun strings and am delighted. The markings for polarity were completely wrong, but I figured it out. The literature talks about the red stripe. The tag was on the end with a blue stripe, with the other end having an unlabeled red stripe.. I used the end with the label, and got pin polarity using the blue stripe. I used the Sparkfun Arduino libraries and example programs to begin development. The library and code were a great basis to evolve my work. I quickly developed a small fascinator using the one string I bought. I have designed the installation to use 18 strings, but now Sparkfun is out of stock. I could not find a phone number to discuss when they might be getting more light strings in. Frustrating.

As noted by other reviewers, the label on these appears to be on the data-out end, not the data-in end. Once that's sorted out, they work quite nicely.

The wire is stiff enough to (mostly) hold a shape, without being so stiff that it's hard to bend. I'm driving them with a Pixel Blaze, and an thoroughly satisfied with the results.

I've been buying from Sparkfun for years and I can't believe they let this garbage out the door. The wires between each LED came with defined kinks as though the strands were tightly folded at some point. While troubleshooting, I noticed one of the LEDs lighting up intermittently and sure enough, it had a broken ground wire right at one of those folded points. These folds have fatigued the wires between every single LED -- making the strands extremely fragile and prone to faulty connections. Now I've got to spend even more money and likely redesign this project for a different set of LED strips with different power requirements. I hope it's not too late to return these.

Edit: Not only was it not too late, but the refund has already been processed! Wow Sparkfun, I knew you wouldn't let me down!

Everything is wrong and I spent over an hour trying to get them to work.

• Only one end works as input
• It's the blue end
• It's the tag end

(Unlike Sparkfun's documentation which says input is the red end; unlike the tag itself which says input is the red end; and unlike other commenters who say the tag is on the output end.)

So... I guess just try +5V on both colored sides, and see which one works for the string you got. Yay.