All About Circuits Forum  

Go Back   All About Circuits Forum > Electronics Forums > The Projects Forum

Notices

The Projects Forum Working on an electronics project and would like some suggestions, help or critiques? If you would like to comment or assist others with their projects, this is the place to do it.

Reply   Post New Thread
 
Thread Tools Display Modes
  #1  
Old 05-28-2010, 01:55 PM
jpferrierjr jpferrierjr is offline
New Member
 
Join Date: May 2010
Location: USA
Posts: 4
Smile Multi-color LED controller

I'm trying to build a circuit that uses multiple multi-color LEDs. I'm wanting this circuit the be able to create all possible colors with one potentiometer. It's really racking my brain (I'm a noob. Also, it doesn't help not knowing anything about ICs). I can easily figure out a 3-4 knob system. But, it just wont work for the application. could anyone suggest anything? I can figure the exact resistance and such that I'll need. I just need a basic layout. Thanks for the help!
Reply With Quote
  #2  
Old 05-29-2010, 03:39 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

That is a tall order, as an RGB LED has three elements that make the colors (now one of the Japanese outfits is including a yellow LED for a better spectrum). See the link - http://www.sparkfun.com/commerce/pro...roducts_id=105

About the only way to get there from a single control would be to use a microprocessor (and perhaps an external ADC for the required precision) to read the control setting and translate that to three PWM streams to control those three LED's.

Someone else may have another approach.
__________________
First comes the hardware, then the software.
Reply With Quote
  #3  
Old 05-29-2010, 04:04 PM
Bill_Marsden's Avatar
Bill_Marsden Bill_Marsden is offline
Super Moderator
 
Join Date: Mar 2008
Location: Dallas, TX (GMT-5 w/ DST)
Posts: 19,022
Blog Entries: 5
Default

It can be done pretty easily with 3 pots. It can also be done with 3 fader oscillators, where the colors come up pretty much at random.
__________________
..
"Good enough is enemy of the best." An old engineering saying, Author unknown.

General info:
If you have a question, please start a thread/topic. I do not provide gratis assistance via PM nor E-mail, as that would violate the intent of this Board, which is sharing knowledge ... and deprives you of other knowledgeable input. Thanks for the verbage Wookie.
Reply With Quote
  #4  
Old 05-29-2010, 05:28 PM
jpferrierjr jpferrierjr is offline
New Member
 
Join Date: May 2010
Location: USA
Posts: 4
Default

Thanks guys. I might of found a solution, though. I found an IC that's made to handle it. I believe it was called an aat3129. I really appreciate your guys' help! Thanks!
Reply With Quote
  #5  
Old 05-29-2010, 05:55 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

The serial digital input is not the same as a voltage off a pot - http://www.analogictech.com/products...rt.php?PID=106
__________________
First comes the hardware, then the software.
Reply With Quote
  #6  
Old 05-29-2010, 06:18 PM
jpferrierjr jpferrierjr is offline
New Member
 
Join Date: May 2010
Location: USA
Posts: 4
Default

Ugh... Yep. I'm a noob. So, what's a serial digital input? Would I need to construct a circuit that translates voltage (from the pot) to faster and slower frequencies? This is much more complicated than I was thinking it would be.
Reply With Quote
  #7  
Old 05-29-2010, 07:40 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

Go to the link and get the data sheet. The serial data is something that would come from a programmed microcontroller. See my post #2.
__________________
First comes the hardware, then the software.
Reply With Quote
  #8  
Old 05-31-2010, 11:40 AM
jpferrierjr jpferrierjr is offline
New Member
 
Join Date: May 2010
Location: USA
Posts: 4
Default

Do you think I could use a pot to control a 555 and use the resultant sig from that into the aat3129 and program the aat to react to different timings? I'm also a newb with "C" programming. But, I could teach myself.
Reply With Quote
  #9  
Old 05-31-2010, 03:57 PM
beenthere's Avatar
beenthere beenthere is offline
Senior Member
 
Join Date: Apr 2004
Location: Missouri, USA (GMT -6)
Posts: 15,815
Blog Entries: 10
Default

No, unfortunately. The serial data carries meaning beyond simple frequency, as the pulses are organized as control words. The controller IC has internal logic that responds to the serial digital control words. The formatting and generation must be done external to the actual controller.

Here is a slightly informative article - http://www.oomlout.com/RGBL/RGBL-Guide.pdf

And a more detailed article - http://www.ledsmagazine.com/features/4/11/2

The 555 approach is one that can work if the timers are set up to do PWM - plus you will need three of them to control each of the three LED's. The only way to have a single input do the full control is with a microprocessor to interpret the input according to a program.

For some experimental fun, look up the topic "color organ" in the forums or with Google. You might find it interesting to make a three channel color organ to drive the LED's.
__________________
First comes the hardware, then the software.

Last edited by beenthere; 05-31-2010 at 04:03 PM. Reason: added thought
Reply With Quote
Reply   Post New Thread

Tags
, ,


Related Site Pages
Section Title
Textbook Special-purpose diodes : Diodes And Rectifiers


Similar Threads
Thread Thread Starter Forum Replies Last Post
AC Fan Motor Controller; Much Help Needed wescat The Projects Forum 22 02-10-2011 06:30 AM
LED Strobe Controller bluerose79 The Projects Forum 11 04-25-2010 07:19 PM
PIC 16F84A to interface with NES controller clabland Embedded Systems and Microcontrollers 3 11-04-2009 03:56 PM
A PWM DC Fan controller with rpm feedback and automatic rpm control! kammenos The Projects Forum 4 08-18-2009 08:17 AM

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 04:13 AM.


User-posted content, unless source quoted, is licensed under a Creative Commons Public Domain License.
Powered by vBulletin
Copyright ©2000 - 2014, vBulletin Solutions, Inc.