It turns out that the sets of battery operated fairy lights at Poundland have an extra feature not mentioned on the packaging. The way it’s been implemented is “economic” but still seems OK.
I also used a couple of 10 ohm quarter watt resistors to convert a 120 LED string for USB use. The current is about 100mA which is quite bright and high enough to keep most “intelligent” USB powerbanks awake. This USB mod will work for most parallel LED strings that don’t have the two-wire multi-channel effects (two channels relying on polarity reversal).
For higher intensity you could use a single 10 ohm resistor, but it would need to be rated at about 1W to keep cool.

If there’s one thing that’s better than a set of dodgy Chinese fairy lights, it’s a set of dodgy fairy lights that have tried to kill a groom on his wedding day. I was sent this set by Phil who got zapped while setting the lights up for his own wedding. The lights also have an LED that has been showing signs of extreme arcing and burning. That’s just the icing on the (wedding) cake.
This investigation has also made me aware of a rather exciting fault condition that could potentially occur with the longer strings of lights.

It’s August, and of course that means that it’s time for retail stores to put up their Christmas decorations! But seriously, if you’re going to do better than the neighbors you need to start now. [Joey] already has his early start on the decorations, with a house-sized light show using LED strips and a laser projector that he built last Christmas.

This was one of my first Arduino projects. After some near misses with bicyclists while running at night, I decided to get some lights so people could see me in the dark. But why stop at boring plain lights? Wouldn’t it be cool if they could respond to my heart rate?

I added seven different light modes which increased in speed with the heart rate: rainbow, raindrop, range pulse, color shot, twinkle, circulatory and Cylon. Most of these modes are self-explanatory.

Knowing different ways of generating light is a great skill to have, so go ahead and add this one to your arsenal by combining a Bugzapper with a CFL Light Bulb.

Sure a CFL(Compact Fluorescent Lamp) works just fine on its own if you have AC mains, but what we’re talking about here is getting the light bulb to work off of a single D battery.

Knowing that the bugzapper steps up the 3V to about 2000V, he decided to see if that same circuit would run off a single 1.5V D battery and achieve the voltage required to drive a CFL tube.

It would be interesting to see how this hack compares to the Joule-Thief method in terms of brightness and run-time.

[Trent] is one of those guys who can make things happen. A friend of his gifted him a mannequin derriere simply because he knew [Trent] would do something fun with it. “Something fun” turned out to be sound reactive LED butt. At first blush, this sounds like just another light organ. This butt has a few tricks up its …. sleeve which warrant a closer look.

The holidays are long over, but we’re still getting a smattering of holiday themed hacks. For this one, the [Han's] family decided to make a Christmas bauble that relays their tweets to them!

Whenever someone tweets with the hashtag #tweetbal it gets displayed on the 20×4 serial LCD display. They’re using an Arduino Uno with an RN-XV WiFly module to receive and send the tweets to the display. A large white plastic ornament ball houses it

This hulking monument to illumination is [DJJules's] 6-foot-long Ultimate Larson Scanner. If you’re scratching your head in confusion, the Larson Scanner is the ever-popular scrolling LEDs seen on KITT (the car) from Knight Rider and on Cylons in Battlestar Galactica (1978), named after the creator of the series.

[DJJules's] iteration consists of sixteen 10W LEDs, each mounted on a heat sink

[James] was wandering around Walgreens after Christmas and found something very interesting – RGB LED Christmas lights that were individually addressable. At $6.50 for a strand of 15 lights, he just had to buy a few and figure out the control protocol. After all, who can turn down a big, cheap, controllable RGB LED strip?

After checking out this light with a scope and logic analyzer, [James] realized there was a very, very simple protocol going on.

[James] wrote an Arduino library to control these strings