LED sequencer

[windell747]

I'm searching for a circuit that would turn on the LEDs in an LED array one at a time. For example, if the LEDs were lined up in a line, the LEDs would light up from left to right or right to left or whatever the order may be. It would be nice if circuit allowed it so that the lighting speed would be adjustable.

Do any of you know of such a circuit that is viewable on the web?

I was going to program a cheap microprocessor to turn on each LED in sequence, but I figured that there might not be enough outputs to control all the LEDs. Not to mention the costs might be higher than needed to make this project work.

 

[Skogsgurra]

Google "shift register". They do just that - if wired to do it.

Gunnar Englund

http://www.gke.org

 

[buzzp]

Back to your micro idea - this could be done depending on number of LEDs by using a MUX or pulse the signals (dont leave them on all the time, humans cant tell the difference very easily depending on the frequency).

Never had the need to do something like this but seems feasible unless you have a 100 LEDs.

 

[itsmoked]

If you have all the micro tools... Use the micro. Inevitable improvements will be much easier... Improvements that might include brightness, modulation, off-b4-on delay, phrenic rate, frenzy modes, delay before start, group motion, etc.

 

[felixc]

Take a look at the 4017. It is called a ring counter, and it can be expanded to infinity. You want to vary the speed? look for the LM555 as your clock source.

 

[VEBill]

Who remembers 'Kitt' (the Pontiac)?

Google: "Knight Rider" LED sequencer

There are plenty of circuits on the

http://WWW for

'back and forth' LED sequencers. Some circuits should be adaptable in case your requirements are slightly different.

 

[sreid]

From an 8 bit output port of a microprocessor you can drive up to 265 LEDs, one at a time. The LEDs are placed at the intersections of a matrix with 16 rows and 16 colums. The rows (say) are driven by high side drivers one at a time from a 4 to 16 seclector IC. The colums are driven by low side drivers one at a time again from a 4 to 16 selector.

 

[benta]

felixc:
"Take a look at the 4017. It is called a ring counter, and it can be expanded to infinity."

No it can't. If you use 2 4017's, for instance, two LEDs would light at the same time, so you have a 2x10 sequence, not a 1x20.

Benta.

 

[zeitghost]

You can daisy chain the 4022 such that only one output is energised at a time.

There's an app note in the Solid State Scientific 400 series cmos logic databook 1984.

I was looking at this for a different application last week.

 

[Skogsgurra]

Make that 256 sreid. Otherwise OK. Question: are you German?

Gunnar Englund

http://www.gke.org

 

[sreid]

Sogsgurra,

Yes, good catch, s/b 256. Spell check won't catch that kind of goof.

Not German, an American living in Santa Barbara California.

 

[Skogsgurra]

You know, Germans say two hundred six and fifty - easily written 265. That's why I wondered...

Gunnar Englund

http://www.gke.org

 

[itsmoked]

I was wondering.. I thought you were saying all Germans are dyslexic..

 

[felixc]

Zwei hundert zechs und funfzen...

I have done ciruits with daisychained 4017s that could expand to infinity. There was a carry bit that enabled this expansion. But anyway the part is obsolete.