Soldering a DIY LED Star for Christmas

Brace yourselves: the holiday season is coming! And therefore I’ve decided to order a DIY package containing all the building blocks for an LED star Christmas decoration. Let’s build it!

The holiday season approached really fast, and I thought I could dust off my soldering skills in the holidays around Christmas. When browsing through some webshops I found the perfect DIY soldering kit at a Chinese webshop. Game on!

After ordering from China it usually takes a while to ship the bought items to The Netherlands. This piece arrived pretty fast, and when I opened the package I found the manual was in Chinese:

Luckily the schematic was really straight forward, so no worries there. The package included the stuff you’d expect for some LED Chrismas decoration: 51 LEDs, a battery holder, some resistors, but most important: the ‘brain’ that’s used to control the whole thing.

The build

I decided to start soldering the LEDs. Maybe it’s the obvious thing to do, but I didn’t want to solder the micro controller first in case I would mess up and kill the whole project as a side effect.

I like timelapses so I couldn’t resist making one:


First thing you think after soldering something completely new to you: will it work? 3/50 LEDs didn’t at first but I was happy the micro controller worked. Another positive thing: the LEDs are so bright they nearly burn my retinas. You never know what you get when ordering online, but this one really delivered!

Everything attached to the board:

Resulting in this!

Writing my own code

The manual contains QR codes which I tried. My Chinese isn’t what it used to be (non existent) but I was happy I found my way around some Chinese Dropbox-like environment. I’ve managed to download the source code! It’s written in C and gives some hints about the way this gadget is programmed.

I’m still wondering how the LEDs work: they have multiple colors but only 2 legs. I’m used to multicolored LEDs having 3 legs: pos, gnd and a leg to send a signal. These work differently, and I think it has something to do with the binary operators I found in the LEDDrive function:

You can attach a micro USB cable to the board, but I’m not sure what it does. There’s also a ‘M1′ port which I didn’t solder anything onto because I didn’t have any part for it. I’ve programmed Arduino before but I have no idea yet what this chip does and how to program it. Time to find out in 2017!


Happy holidays!