Components: RGB LEDs

Components: RGB LEDs

/ January 27, 2013 / Comments Off on Components: RGB LEDs / Technology

One of the toughest jobs of working with electronics is going through a huge list of components and finding the right ones for our concept prototypes. With nothing in hands reach, my task was to going through various electronic websites such as digikey, sparkfun and adafruit, looking for parts.

Our first prototype, codenamed “Scales”, will display the intensity of activity within a space through panels of LED lights. We needed a large amount of RGB LEDS and we need to be able to control the R, G and B individually through an Arduino. There are several factors that will determine which LED we should use based on the Scales’ design specifications. For our prototype, we will be creating 72 panels each with multiple LEDs housed inside of them. This means the LEDS need to be bright enough from a distance and cost efficient since we will be needing a lot of them.

After a good number of hours of detective work, I was able to nail it down to a small list of potential LEDs, and listed them down below with a short product description and specs. In our list we have  the “regular” RGB LED, SMD LED, Triple Out High Power LED, Piranha Super-Flux LED and the RGB LED Chain.

  • The regular RGB LED is a good starting point for prototyping. They are inexpensive, versatile and fairly bright. There’s also a high probability that we could be using these in our final prototype.
  • SMD LEDs aren’t what we look for at the moment for the “Scales” concept, because they have lower luminosity than the regular RGB LED. One very good advantage is that they are very tiny. They might be useful for the other concepts.
  • The Triple Out High Power LED seems to be a good choice because it’s super duper bright (3W). Unfortunately, the price tag of $14.95 per unit is a bit high. If we were to use lets say 1 LED per panel, it will lead to a total cost of 72*$14.95 = $1076.40!!
  • Piranha Super-Flux LEDs are awesome! I’ve used them in a previous project and they very bright! They will burn your eyes if you look straight into them. And they are only $0.95 per unit (common cathode)!
  • RGB LED Chain. What can I say? 20 addressable LEDs in a single chain. No need to create/solder any additional circuits to make them run, because you’re able to control them through software.

So for our first “Scales” prototype we will be using the RGB LED Chain, because we don’t have to spend much time soldering and worry about how to drive all the LEDs. We can focus our effort on further developing the concept and fine-tune the interactions. Now, the question will have to answer is, will they be bright enough for the final prototype? If we do end up needing high luminosity LEDs, we should highly consider the Piranha Super-Flux LEDs as our light source.

 

1. RGB LED (regular)

These regular RGB LEDs are great for testing purposes. They are inexpensive and quite bright on maximum light intensity.

Product url:

Specs:

  • 5x35mm (D*L) round head
  • Luminosity (RGB): (800, 4000, 900)mcd = 5700mcd total
  • 4 pin terminal, common cathode

2. SMD RGB LED

Very tiny. These are great when you need a lot of color from not a lot of board space, but they aren’t really that bright compared to the regular RGB LEDs.

Product url:

Specs:

  • 5×5.5mm (D*L)
  • Viewing angle: 120 degrees
  • Luminosity (RGB): (250, 880, 180)mcd = 1310mcd total

3. Triple Out High Power RGB LED

Do not look into the light. You know you want to, but boy will you be sorry. With all three LEDs at 350mA per channel (3W total output), you will need additional heat sinking. This will certainly be bright enough for any prototype we might want to build. Downside is the price of $14.95 per unit.

Product url:

Specs:

  • Viewing angle: 140-150degrees
  • Luminosity (RGB): (30-40, 40-50, 10-15)LM = 105LM total (22546mcd)

4. Piranha Super-flux RGB LED

Nice and bright LEDs that come in common cathode and anode. Note: multi-LED driver chips (such as the TLC5940/TLC5941) are often designed exclusively for CA and can’t be used with Common-Cathode.

Product url:

Specs:

  • Viewing angle: 90 degrees
  • Luminosity (RGB): (1500, 4000, 1500)mcd = 7000mcd total

5. RGB LED Chain – 20 LED Addressable

This chain of addressable RGB LED lights is composed of 20 individually sealed 10mm RGB LEDs and drivers. The driver for this chain is our old friend, the WS-2801 constant current LED driver. The 2-wire control scheme allows you to control the entire chain over only two GPIOs and because data cascades across the drivers, you can chain as many of these together as you can power!

Product url:

Specs:

  • 20 LEDs per chain
  • Luminosity (RGB): (29, 81, 27)LM = 137LM total (29400mcd) per 1m/32LED