LED Sequencer Q's

[WilliamN]

I am building a LED sign. I have serries paralleled the LEDs to form letters. What I am trying to accomplish is drive each letter one at a time, then latch it. Ie if I had my name "BILL" laid out in a LED pattern. I want "B" to light up then latch(stay on) then "I" and then "L" and so on. Then once the name has been completley lit up have the whole thing flashes a few times, then resets. I am sure there is an easy way to achieve this, I just can think of one. I dont think i can use a 4017, since the previous pin goes low when the next goes high. Any pointers? I will use npn transistors to switch all the segments. Thanks for the help!
William

 

[Agent 009]

You could easily make up a sequential logic circuit with flip-flops, having states turning on each letter, then keeping it on while lighting up the next one. The last states would flash the whole thing... I dunno what r ur restrictions though, if u're allowed 2 use flip-flops or so...

 

[Agent 009]

And u need a clock generator... All I can think of right now is a simple 555 timer...

 

[ThermalRunaway]

In order to accomplish that design all you really need is a logic circuit to control the switching of each of the displays (each letter being a seperate display in it's own right), and then some form of output circuit to power each letter.

Are you familiar with simple logic design?

Brian

 

[Agent 009]

what's a 4017 anyway ?

 

[WilliamN]

A little, thats why I am working on this project to help learn more.
Thanks for all the info! Any more ideas as to how I can accomplish this.
thanks again
William

 

[k7elp60]

Here is a circuit I developed a couple of years ago for my girl friend. I drew the schematic on the computer today.
I flashes the individual letters in sequence fairly slow. When S1 is depressed the letters start to flash. After about 5 sequences it turns itself off. If you wanted the letters to flash all the time you could eleminate U1 and ground pin 12 of U2 and delete the 2N3906 transistor with a jumper between the emitter and collector terminals.
The one I built also played a melody for the same time. I didnot draw the melody circuit, as the melody generators by Holtek are no longer available.

 

[ym2k]

I am building a LED sign. I have serries paralleled the LEDs to form letters. What I am trying to accomplish is drive each letter one at a time, then latch it. Ie if I had my name "BILL" laid out in a LED pattern. I want "B" to light up then latch(stay on) then "I" and then "L" and so on. Then once the name has been completley lit up have the whole thing flashes a few times, then resets. I am sure there is an easy way to achieve this, I just can think of one. I dont think i can use a 4017, since the previous pin goes low when the next goes high. Any pointers? I will use npn transistors to switch all the segments. Thanks for the help!
William

From wat i thought, pic controller is the easiest way you can use. You just need a mosfet to drive every series of your led character. A typical pic 16f628a can give u 10+ characters chain. If you are looking at a more complicated or lengthy words with more control, i will suggest using DMX interface. DMX is a good interface for leds control. You can make a good search by just typing DMX in any search engine.

 

[FRIED]

Try this. Not tested. EDIT Altered