[Lab] how to control several RGB LEDs with Arduino

[Peter Sjoberg]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 08/01/2014 09:36 AM, jslei033 at uottawa.ca wrote:
> My prefered chip is the TLC5940: it cam be daisy chained, you can vary
> each pin's brightness, and it controls 16 outputs at once. You can also
> use the WS2801 family of chips (some control one LED per chip, some
> control many LED per chip).
> 
> 
> You're on the right path, thinking of pwm extenders.
> 
> 
> The ws family is cheaper but the tlc are more heavy duty.

I guess it depends on how many LEDs you plan to control.
I was playing with 8x8 RGB matrix and for that I ordered DM163 and while
they arrived I haven't taken the time to play with it.
What I liked about it is that you can set constant current on each color
and it seems like the 8+6 is so that you set one for each individual dot
and the other for over all display light level.

from http://www.siti.com.tw/product/spec/LED/DM163.pdf

General Description
The DM163 is a LED driver that comprises shift registers, data latches,
8x3-channel constant current circuitry with current value set by 3
external resistors, and 64 x 256 graylevel PWM (Pulse Width Modulation)
function unit. Each channel provides a maximum current of 60 mA. The
grayscale data are separated into BANK0 and BANK1 respectively, selected
by SELBK pin. BANK0 is 6-bits grayscale data and the BNAK1 is 8-bits
grayscale data. Depending on the system requirement, both PWM banks
could be utilized jointly to achieve maximum 8+6 bit grayscale performance.
Alternatively, users can choose either 64-graylevel bank or
256-graylevel bank for dot correction, and the remaining bank as
image data. DM163 could also be constructed as a PWM controller for LED
drivers. When VDDH is connected to VDD, each of the 24 output channels
outputs can act as an inverse digital signal for controlling the LED driver.

Features
* 24 Output Channels
* 8 + 6-bits PWM grayscale Control
* Constant Current Output: 5mA to 60mA
* LED Power Supply Voltage up to 17V
* VDD=3V to 5.5V
* Varied Output Current Level Set By 3 External Resistors
* Serial Shift-In Architecture for Grayscale Data

> 
> 
> On 14-08-01 8:59 Olaf Baumann wrote:
> 
> Hey Lab,
> 
> I got some RGB LEDS to play with but when I count the number of pins I
> need, it doesn't look like I can drive very many.
> 
> The UNO has six PWM output pins and each RGB LED needs three.  As the
> saying goes, twos company, but I want a crowd!
> 
> With regular LEDs, I used cascading shift registers to allow me to
> control 24 of them.  A great success in my temporarily blinded eyes.
> 
> Is there an analog analogue to the digital shift register?  It seems
> that PWM is a hack for a voltage level, would a steady voltage be
> better?  SPI or I2C would be bonus--maybe I could use an ATtiny85.
> 
> thanks,
> Olaf
> 
> 
> 
> 
> _______________________________________________
> Lab mailing list
> 1. subscribe http://artengine.ca/mailman/listinfo/lab
> 2. then email Lab at artengine.ca to send your message to the list
> 
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/
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=zYXT
-----END PGP SIGNATURE-----