Introduction: Rainbow Jar - RGB Pixel Strip Controlled Via Arduino

About: A member of instructables since 2006 I'm currently cruising at an improving 0.917 instructables a year...

Our most popular item on our display at Maker Faires is always the Rainbow Jar. One customer has already replicated it so we thought we'd share how we made it so you can make your own! (tried embedding this vine but it breaks instructables!)

Step 1: Getting Started - What You Need

This is all the stuff we used. 

What You'll Need

50cm of Addressable LED Strip

Plastic Sweetie Jar (found them on eBay)

Arduino Uno

Pin Headers (UK)

Stripboard (UK)

Rainbow Wire

5V Power Supply

Something to diffuse the light - we've used RGB LEDs!


Soldering Iron and Solder

Wire Strippers

Craft Knife and Ruler

All of the links are to our site - in the US you can get everything from Adafuit or Sparkfun

Step 2: Preparing the Strip

The strip is controlled by an Arduino, using two control wires Data and Clock. We're attaching green to the data and yellow to the clock. Orange to the +5V and Blue to the GND

Remove the red and brown wires from the rainbow cable and keep them for later. Strip the four wires at once using the super cool and handy Hakko Cutters.

If you're using our Rainbow Cable then bend the orange and blue cables out a little. A little bit of solder added to the tips of the wire will help them adhere when you hold them onto the pads and add some heat from your soldering iron.

Step 3: Make a Shield!

Now we make a little shield for the Arduino.

Take the pin headers and snap off two lots of four pins. Put them into the Arduino, you'll want them in the 0,1,2,3 on one side and the Vin GND GND and 5V headers on the other side.  Put the strip board on top and mark up how much of the board you need. They're not opposite each other so you won't need to do anything with the copper on the stripboard.
Score along the lines of what you need on the stripboard and snap it along the score lines.

Now we do a little alteration of the pin headers, pushing them down on a hard surface until the black plastic bit is flush with the hard surface. That way we can put the plastic bit on the side of the stripboard with no copper and have a nice bit to solder onto the copper.

Strip the other ends of the rainbow wire and solder the Clock and Data Pins to the strips that line up with 3 and 2 Respectively. Don't worry if you do them the other way by mistake, you can change it in the code!

Solder the blue in line with one of the GND Pins and the orange in line with the 5V.

Step 4: Add External Power!

This seems to run fine as it's only 50cm of strip through the Arduino, but lets make it a bit future proof adding external power, using a cool 2.1mm female jack.

Using a bit of the red and brown wire we cut earlier attach to the 5V and GND lines on the shield we just made. Attach the 5V to the +ve on jack connector and GND to the -ve.

Step 5: Program the Arduino

Now lets give your project some brains!

Download the awesome library from Adafruit.
Unzip the library and put it in your Arduino libraries folder. 
Attach your Arduino to your PC via a USB cable and boot up the Arduino IDE load the Stringtest example and change the length to 16 LEDs.

Upload to your Arduino and try the shield out! The test is very pretty, watch it! If it's not working, check your soldering and that you have the clock and data the right way around.

Step 6: Prepare the Jar

For whatever reason the jar looks better with the light going from bottom to top, also it's more stable with the cable in the bottom.

So it's time to introduce the knife to the plastic jar, it cuts well but be careful. Cut away from you.

You want a nice neat letter box to slot the strip through.

Step 7: Thread the Strip, Coil It Up and Add Your Diffuser and You're Done!

Thread the strip through the letter box you've made then coil it up and hold it towards the back of the jar. Now start adding your diffusing materials. If you've left the strip running like it did you'll see it take shape and be able to adjust the strip and diffusing material to make the best jar you can.

Edit here that needs some photographs. I went back and repacked the jar. This time using a roll of bubble wrap in a sausage shape to attach the strip to. Then the internals of the wrap don't take up your diffusing materials an keeps the tape neat so you can have it at the back of the jar.

Once done. Stand back and admire your work!

Step 8: Fin!

Stand back and admire your work. Oh it looks best in the dark, so either wait until it's dark or turn off the lights (or build a box like I just did!) Let us know what you think!

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