LED Sequencing

[someusername]

Hi All! I'm new to this board, but I have to say I like what I've seen so far. I am trying to build some type of controler to control multiple LEDs and make them light in a specific sequence. I am not completly new to working with electronics but I want to have a good idea what I'm trying to do. Any information anyone can garner would be really appriciated. Thanks!

[Mike]

A PIC could accomplish that easily, you could even computer control it and stuff.<p>But you said you are new to electronics, so that may be too compilcated.<p>can you describe what you need with more detail? Like what sequence, speed, etc.

[hp]

If the sequence is linear then you could use a LM555 as a clock source and a CD4017 as a decade counter to control your LEDs. You could arrange the LEDs in different patterns to achieve different sequences.<p>Harrison

[wd5gnr]

A PIC could do this. However, if you are just getting your sea legs in electronics, you may find the Basic Stamp easier to work with. They are at http://www.parallax.com. I maintain an unoffical Basic Stamp FAQ at http://www.wd5gnr.com/stampfaq.htm.<p>If you do want to work with the PIC (or an Atmel AVR) look at these tutorials

[someusername]

Thanks to all of you for your help. I'm sure answering Noobie questions all the time gets old, but it really is nice to find a place to solve my ignorence. Anyway, as for more information, I have anaray of LEDs in a line like:<p>---- ---- ---- ---- ----<p>I want to light them in sequence something like:<p>1. ---- ----
2. ---- ----
3. ----
4. ---- ----
5. ---- ----<p>I would like it to change rather quickly.<p>Anyway thanks to everyone for you help. I wish I could give a better description of what I want to do. I hate not knowing what I'm talking about. I guess we all have to start somewhere though.

[someusername]

sorry my last post messed up. I have a line like:<p>- - - - -<p>and I want it to be like:<p>- -
- -
-
- -
- -<p>and so on. Thanks.

[someusername]

well, this is frusterating. Just imagin it starting at both ends, then moving in by one on both sides, then just the middle, then the two on either side of the middle, then the outside again. basically an X. anyway, thanks.

[haklesup]

An LED sequencer can be made with a counter chip or a bunch of flip flops (for a little more control)<p>Basically the chip is clocked by an oscillator (can be a 555 circuit) which causes the output pins to change state in the designed sequence. Each output pin drives 1 LED. <p>By designing a counter circuit out of flip flops you can design almost any sequence you want. Its a little technical but if you read the first 4 chapters in a Logic design text then you will learn about state machines and how to design them.<p>For a simpler design you can use a 4 bit Binary counter chip like the 4029 and then put its outputs into a 4 to 16 line decoder or a 7 seg LED decoder chip (4511) and use those outputs to drive the LEDs. (not nessary to use 7 seg led or arrange LEDs that way, you can put them wherever) There are many chips in the flip flop, counter and decoder categories so you can have some choices. <p>The 74LS and 74ALS and 40XX chips can drive an LED directly but the 74HC and 74HCT devices will need a transistor between the output and LED.<p>There is more than one way to do this but low cost logic chips are easy to get and cost very little. The effort to design with them is more since their functions are basic.<p>Sorry, no turn key solutions here

[paulrevelcet]

Go to this site http://www.doctronics.co.uk/4017.htm
and you will find what your looking for, great web site.

[someusername]

Thanks All For Your Help!<p>paulrevelcet, You were quite right, that is a great site, Thank you!

[Lin Farquhar]

Have a look at
rev-ed.co.uk
They supply a bootstrapped PIC chip series, programmable in BASIC. Software is a free download, and the programmer is 2 resistors and a D9 plug outta your serial port. Full tutorials are provided with the software, and the chips will drive leds directly.
Rgds, Lin