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LED Flash Pattern

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I am modifying my computer case with LED's. I am making holes and wanted the LED's to flash on and off like they were moving.

Like this (sort of): 1=On 0=Off

1000000000
second later
0100000000
second later
0010000000

It seems like it would be a really easy thing to do but I don’t know much about electronics. Also if any one knows a good book that I can start learning how all the electronic parts (resistors, capacitors etc.) work with each other that would be great.

Thanks,
Kyle
 

nettron1000

New Member
I think you are referring to a sequecial LED flasher circuit. How many LEDs will you be using ?

a 74154 IC can sequence 16 LEDs, a 4017 IC can drive 10, a 74138 can drive 8, etc.

Also do you just want sequencing in one direction or are you interested in a back and forth ,left/right-right/left changing sequence (think of the nightRyder car ).
 
How many LEDs will you be using ? Guessing 12

nettron1000 said:
A 74154 IC can sequence 16 LEDs, 4017 IC can drive 10, and a 74138 can drive 8, etc.

Also do you just want sequencing in one direction or are you interested in a back and forth ,left/right-right/left changing sequence (think of the nightRyder car ).
Left and right would be cool if that would not be to complex for me. All I have ever done right now is build two kits; electronic dice, and a message scroller. I have build a little bug type this that moves around on two motors that are powered by two AA batteries and it has two switch buttons so when it bumps in to something the motors reverse and it keeps going.

My knowledge of how to put things together so they work is not good at all I know what all the electronic parts do just not how they work together. I wanted to know what might be a good book for me to start.

Thanks,
Kyle
 

laroche73

New Member
led sequencers

Just something to be aware of, the 74138 and 154 are decoders, and require a binary counter on their inputs (3, 4 bits respectively) to drive them as sequencers. The 4017 is a fully decoded 5-stage johnson counter, so you can do the sequencing with a single chip (you also need a clock source), though the output pattern is limited. The decoder ICs are a better choice if you want more complex sequences, i.e. an up/down binary counter driving a decoder can give you a back and forth sequence.

If you're feeling ambitious, you may want to play around with n-connected type sequencers. They require drivers having three output states; 0, 1 and high-impedance. You can drive lots of leds with few lines, as long as you only need one on at a time.

(N^2 - N) leds can be driven from N lines. Using the 6 I/O lines on a little micro like the PIC12F629, you can drive up to 30 (6^2 - 6) leds. Similarly, you could drive 12 leds with 4 output pins. I'd suggest using high-efficiency, low-current leds here.

Getting into micro's may be more than you want to do right now, but it's worth getting your feet wet at some point.

http://www.electro-tech-online.com/custompdfs/2003/09/muse152.pdf (page 4)

Microchip also has an app note describing the n-connectedness idea.
 

Electric Rain

New Member
Ok, about the in/out fading. Try messing around with the schematics found on the part of this webpage that says "Fading Red Eyes": http://ourworld.compuserve.com/homepages/Bill_Bowden/page5.htm

And the LED Chaser, you can do 12, but it would be soooooo much easier if you did 10: http://www.aaroncake.net/circuits/chaser.htm

Both of these circuits run off of 9V, so with the help of a voltage regulator you can power one, the other, or both of these circuits with power from the inside of your PC. :wink: Let me know if you need more help.

Oh, and by the way, if you don't mind me asking... what are you doing with this?
 
Electric Rain: I assume that your question was to me.

I am thinking about either using it as a hard drive light or put it in my car to show the depression of my gas peddle. The hard drive light project has been done so I might go with the car idea.

Thanks for all the help guys I have really learned a lot.

Kyle
 
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