Arduino Powered RGB LED Vodka Shelf

This instructable will get you going on making your own arduino powered Red Green and Blue LED project. It doesn't even have to be a shelf! Vodka bottles just happen to light up nicely so that is what I chose to do.

In this project we use every pin on the Arduino to achieve as much control over a set of LEDs as we can. The functionality of the vodka shelf includes:

1. Power 8 sets of two 4 pin RGB LEDs
2. Create two separate colors which are staggered across the surface
3. Turn on and off any set of LEDs
4. Micro controller control of the color and lighting patterns 
5. Optional manual control of the LED colors using knob potentiometers

Background: 
Your eyes are sensitive to only three colors: Red, Green and Blue. All other colors excite the RGB receptors in your eyes in different proportions allowing you to interpret that color. Thus by sending certain amounts of Red, Green and Blue wavelength light into your eyes it appears as though you are seeing different colors. This is how your TV works, if you look really closely you'll see its made up of many small R,G,B lights. We experience this every day. Its just really cool to be able to control it for yourself. I was amazed to when I turned on the Red and Green lights and Yellow appeared.

Examples
R+B = Magenta,
R+G+B = White
G+B = Cyan

The easiest way to control the relative amounts of light we get from each LED is by using Pulse Width Modulation (PWM). Instead of turning the lights slightly on by applying a lower voltage we turn them completely on then completely off for a given amount of time over a short cycle. For the arduino, this cycle is approximately 500 Hz. Our eyes respond too slowly to see the fast blinking and they give us the average over time, approximating having partially turned the light on.

Step 1 Materials

Here are the materials you need. The amounts may vary depending on what you choose to build so here is what I used:

-16x RGB LEDs:  These are actually 3LEDs built into one casing. They have 4pins, one for each LED anode (+ve) and one common cathode (-ve). These are easy to find on the internet and can be found cheap on ebay. I paid $10 for 50. A good current rating is around 15mA (per internal LED).

-3x 100K Potentiometers: I used knobs

-1x Push-button

-Protoboard or breadboard + wires, an arduino prototyping shield is ideal.

-16x 2N3904 N-channel Bipolar Junction transistors, very common and inexpensive. Ebay.

-6x 10 Ohm 1/8 Watt Resistor
-8x 1K Ohm 1/8 Watt Resistor
-8x 100 Ohm 1/4 Watt Resistor
-8x 64 Ohm 1/4 Watt Resistor
-8x 56 Ohm 1/4 Watt Resistor
-1x 10K Ohm 1/4 Watt Resistor
-3x 56K Ohm 1/4 Watt Resistor

-Length of ribbon cable

-Ikea shelf

Comments

[micobanff]

By the way, the original reason I wanted to post a comment... Great job! I was looking for something like this... but just one colour... I love those IKEA floating shelves.
My idea was a lot simpler... to construct a shelf that had momentary push button switches that when you put a bottle down, the LED beneath the bottle lit up.
This seems like a much more interesting project though. Arduino has always been a huge interest to me, maybe I will take the plunge. And drinking games are always a fun thing!

[lartist1]

Interesting project, but the BJT symbols in the schematics are for PNP type, not NPN as they are supposed to be.
Also, each LED should have its own current limiting resister before connected in parallel. Without resister, they can have "thermal runaway" problem. Whichever the LED that draws more current (due to the variation in manufacturing) gets hotter, which makes it to conduct more current (by taking it from another LED next to it), making it even hotter, and so on. Having the resister for each LED will remedy this problem. (Even though with the resister values you have here should not cause catastrophic failure, correct design basics should be mentioned.)

A bit disappointing to know that there is not checking by Instructables about the validity of circuit. Because I see this site as an educational rather than entertainment.

[micobanff]

I think to start checking the validity of each instructable would be a very difficult job for instructable employees... especially since there are many different categories.... Yes, theoretically somebody could check over these to make sure there is nothing missing in the circuit... Could you imagine a job where 8 hours a day you were paid to read over user submitted instructions, that do not have the same format? And employing pastry chefs, engineers, scientists, mechanics, etc... all in one place? And there are is more than just one way to solve a problem when it comes to life. How do you judge an instructable that tells you how to grow tomatoes? If you talk to 10 different gardeners, you will get 10 different answers. And then what? Have these moderators amend these errors and omissions, or send the instructable back and say they can't approve it?

I think if instructables were moderated, it would defeat the purpose of this community, and then nobody would submit them because it would be such an annoying and tedious process to be approved. I think that's why we can comment on instructables, which is why the warning below says positive (good job) and constructive (your symbol is wrong and you should have resistors in there)

[Waterfox51]

Good catch, I updated the figures to correct this.

I agree that wiring LEDs in parallel is bad practice (par 4), but i don't see how adding a resistor in series with each LED will solve this problem unless their resistivity has a negative temperature dependence much greater than the positive rate of the LED.

Nice call out to instructables.

[lartist1]

About the LEDs in parallel, this page has two good answers:

http://www.instructables.com/community/Parallel-Circuit-question/

I echo westfw and NachoMahma.

I know your circuit works just fine in most conditions. Even if one of the LEDs steals most of the current, it won't be more than around 35 mA-ish.
Problems will only arise when you start using higher current to drive LEDs.
You don't need negative temperature coefficient - just some resistance is enough to remedy thermal runaway. We are talking about the temperature inside LEDs anyway.

[afwiggith]

I'll have to do this one in my house, it will give me an excuse to buy Crystal Skull vodka like I see in this picture. I'm hoping that you actually drank all of this vodka and didn't waste it...? In all seriousness, this looks awesome!