Pooface

I think this is what I want to make

I am looking to make a chasing or even just flashing LED array of somsort in my computer. I got 200 on the way and wondered if anyone had any know-how.

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elpha

hmm, let me see if i can find a link..

here we go

not quite the same, but a good start.

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pixelbend

It stuff like that that makes me want to go back to school and study engineering.

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tman17m

well im not sure if this will go over your head or not...i dont know your skill at circuits but we shall give it a try..

what you need is a multi stage counter. its relatively simple to build. the first stage is a 555 timer circuit. build the osciliation around how ever fast you want your leds to chase, or make it variable so you can adjust it. feed the output of this into a 4017 decade counter. pretty standard chip, but heres some info:
http://www.st.com/stonline/books/pdf/docs/2029.pdf
anyway, i know there is a cheaper decade counter chip out there, just dont remember off the top of my head right now. so, you just get as many counter chips as you need and drive them all off the 555 counter. each led would be tied to an output (0-9) (of course with the right resistor). the leds would be put in sequence and would chase eachother!

hope this helps

Pooface

YEs that PDF is pretty good. Im not worried how fast they chase at all so what is it that would go before that. And would that plug into the CLock? What would go into all that other stuff on the chip? Vdd, Clock, reset, Clock inhibit, carry out.

Where in the world can I buy these.

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jujueye

Well, I would start with the small kit to get your skill level up. Just getting a handle on solder irons takes some time. Let's face it, you can easly burn up lots of components simply by applying too much heat. Better to try it on something that's not your main project!

mercury-hg

the datasheet that tman17m offered is for the counter, which takes the clock as an input, amongst other things. the datasheet describes what you would want to do with the various other leads, but in general you can tie reset and clock to ground (you don't need them) and you can leave carry out open, because you're only using the one counter, not multiple counters necessitating a carryover.

tman17m

yup basically what mercury said. the output of the 555 timer circuit goes to the clock pin on the 4017. all the other pins like mercury said. and you are good to go

the420star

if you can tell me what that two ICs are that come in that kit are that would make a huge diffrence... and to be honest i think this can be done without a 555, my experiance with 555s are that they are a pain in the ass... but give me a little bit... i am paying all this money to become a EE i hope i can do this...

Oh flashing is real easy... that i can tell you how to do no problem...heck if you want flashing i will even send the pspice drawing of it...

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saltfish

I second the reccommendation that a 555 and a 4017 decade counter be used.

Hint: use a small ceramic cap and a large >500k ohm resistor. You can use a ceramic or mylar cap and a variable 300k resistor and a 0-200k variable resistor. This will make the 555 clock at a variable rate depending on the position of the variable resistor.

You could also have luck with a >1M ohm resistor and a varaible cap.

I have done this before.. ..and I told myself to remember the order of the pins on the 4017, the pin order is not linear around the chip.

-SF