IC question

ENT2151 · Post by **ENT2151** » Sun Feb 04, 2007 5:20 pm

Hello, does anyone know of an IC chip that if hooked up correctly, can support 3 LEDs (call them A, B, and C). when it is turned on one optional pattern would be to go from A to B to C and back to A all in about 2.5 seconds. Also does anyone know of an IC chip that will dim an LED and then brighten it, and then dim it again, etc.? Any help will be apreciated, thanks.

jwrjr · Post by **jwrjr** » Sun Feb 04, 2007 11:47 pm

I've never heard of such chips. But then, I would program single-chip computers to do that. As the single-chip computers can be purchased for less than $1 each, that way would probably be cheaper.

ENT2151 · Post by **ENT2151** » Mon Feb 05, 2007 11:52 am

where does one buy those, and how exactly would they be programed?

Umi_Ryuzuki · Post by **Umi_Ryuzuki** » Mon Feb 05, 2007 12:21 pm

Some basic circuit diagrams here.
Alternating flashing circuit
http://www.electronic-circuits-diagrams.co...htsimages/1.gif

Main page
http://www.electronic-circuits-diagrams.com/index.shtml

10LED sequencer
http://www.aaroncake.net/circuits/chaser.htm

16 LED sequencer
http://ourworld.compuserve.com/homepages/B....htm#4017-2.gif

Also have a look around the Model train section of your hobby shop.
There is a company called Model-lec? that makes a bunch of different
PCBs that will imitate police cars, school buses, Fire engines, construction
baricades, etc.

Here is an online train store that lists a few others.
http://www.ngineering.com/lighting_effects_products.htm
And the surface mount LEDs the have are sooo tiny

jwrjr · Post by **jwrjr** » Mon Feb 05, 2007 11:31 pm

Where to buy programmable chips? Companies who carry such include Mouser, Digikey, Jameco, and many 'robotics' shops - all accessible online. The equipment to program them, as well as some of the chips, can be found at any of the above businesses or even Ebay.
The easiest (and cheapest, unless you want to do it yourself) is to find somebody who already does this sort of thing. There are several of us around.

Sparky · Post by **Sparky** » Tue Feb 06, 2007 6:20 am

Sounds like a johnson circuit 4017, with a 555 timer circuit for the change rate. and teh triangle wave op amp circuit for the dimmer effect. both are chips are talked about in the electronics help sticky at the top of this area of the forums.

jwrjr · Post by **jwrjr** » Tue Feb 06, 2007 11:37 pm

The nice thing about programmable chips is that you can put some fairly complex functions in a single chip (2 chips if you count the voltage regulator).