RGB LED Shield


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An RGB LED shield would be great. We could make a tiny lamp.


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An RGB LED shield would be fantastic especially in a grid type layout. Horizontal or Vertical strip configurations are also quite popular with hobbyist's. Adafruit has many products in strip (flexible, etc.), grids (5x5, 8x8, 16x32, even 32x32), ring configurations (12 and 16 LEDs), the list goes on. I think there is no question people would love a set of TinyDuino shields to make message buttons, jewelry, marquees, signs, even LED pixel monitors (see end of post for many projects).

The smallest RGB LEDs I could find were these- the QuasarBrite 0404 RGB LED. They are in a 1 mm x 1 mm x 0.25 mm package size. The package provides a 120° viewing angle low current requirements, i.e., Red:30 mcd, Green:40 mcd, and Blue:20 mcd @ 2mA according to the product brochure. Mouser lists them for 1.20 a piece, 0.665 for 100, 0.399 for 1000 and Digi-Key quotes 0.35378 for 2000.

Just rough measurement calculations and concepts follow:
Using the TI TLC59116 16-Channel Fm+ I2C-Bus Constant-Current LED Sink Driver 16 LEDs can be driven. The TLC59116 is about 5.8mm x 5.8mm, so on a 20mm x 20mm board (I know the mounting holes and connectors take away from that) maybe 9 TLC59116's could be put on one side of a board. That's 9 controllers x 16 lines = 144 controlled LEDs. That would be a 12x12 single color LED matrix that could be put on the other side of the board. With 144 lines with 3 per LED, that would be 48 LEDs a 8 x 6 matrix. That is a CRAZY HUGE amount of lines, resisters, etc. but it would be amazing to see.

Perhaps more realistically, 4 TLC59116 controllers for 64 controllable lines which would be an 8x8 single color matrix. For an RGB setup, 64 lines could support 21 LEDs. A 16 LED Neo Pixel Ring type setup requires 3 TLC59116 controllers for the 48 lines.

Real layout work would be tough enough, power draw needs to be addressed (probably close to 1.21 GigaWatts! oh wait that's for a flux capacitor) 2mA per LED for the QuasarBrite, and soldering would be... well a pain I suppose.

More Controller Options:
The TI TLC5951 is a 24-Ch 12-Bit PWM LED Driver (6.8 mm x 6.8 mm). Even more LED madness could ensue using this beast!
TLC5951 Datasheet: http://www.ti.com/lit/ds/symlink/tlc5951.pdf

The MAX7219/MAX7221 are compact, serial input/output common-cathode display drivers for driving 7-segment numeric LED displays of up to 8 digits, bar-graph displays, or 64 individual LEDs. They are pretty sizable, but could be fit on one side of a TinyDuino Shield.
MAX7219/MAX7221 Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX7219-MAX7221.pdf
Arduino Interface Info: http://playground.arduino.cc/Main/MAX72XXHardware#.UxQMuvldWSo

MAX6950/MAX6951 drivers are the only choice for systems where 3V or 3.3V is the highest supply voltage available. Their lower logic input thresholds also allow them to be interfaced directly to a microprocessor running from as low as 2.5V.
MAX6950/MAX6951 Datasheet: http://datasheets.maximintegrated.com/en/ds/MAX6950-MAX6951.pdf

LED matrix projects: (All of which I think can become wonderful TinyDuino projects)
Building huge displays with LED strips: http://www.pjrc.com/teensy/td_libs_OctoWS2811.html
64pixel LED Display: http://www.instructables.com/id/64-pixel-RGB-LED-Display-Another-Arduino-Clone/
AdaFruit's Neo Matrix Library: http://learn.adafruit.com/adafruit-neopixel-uberguide/neomatrix-library
LED Matrix Link Project: http://www.mobilewill.us/2013/03/led-matrix-link-prototype.html
Meggy Jr RGB: http://wiki.evilmadscientist.com/Meggy_Jr_RGB
Peggy version 2.0: http://www.evilmadscientist.com/2008/peggy-version-2-0/
16x8 LED dot matrix with MAX7219 module: http://www.instructables.com/id/16x8-LED-dot-matrix-with-MAX7219-module/
Jameco LED Matrix Kit Schematics: https://www.jameco.com/Jameco/Products/ProdDS/2127970.pdf
« Last Edit: March 16, 2014, 07:59:30 PM by tinybuilder »


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