Newbie Sequential LED Help

[Ian D]

Hi,

how about an LM3916?
http://www.national.com/ds/LM/LM3916.pdf

Select the dot mode. The required LED is then chosen by the amplitude
of the audio.

And it will run on 3V


Cheers,
Ian Du Rieu
The Leon Audio Co
http://LeonATdio.com.aT

To reply, replace "T" with "u", twice.

 

[Si Ballenger]

sci.electronics.misc might have been a more apt group, but
(as you have seen) your courtesy and good descriptions of problems
can put folks here in a forgiving (and reflective) mood.

Have you tried getting more fiber in your diet to help you get
that " forgiving (and reflective) mood"? ;-)

 

[Si Ballenger]

Mr. Pinnell, all I can say is W--O--W! I was really worried about how
I was going to make this happen, but not any more!

**I am going to Radio Shack to pick up parts after school tomorrow and
work on this over the weekend. Thank you, thank you, thank you!!!!!!!!

The 4017 chips are hard to find at RS now, but All Electronics
http://www.allelectronics.com/ has an "led chaser kit" (cat#
AEC, $6.50) that might be of interest for your project. I made a
sequential webcam switcher using this type of setup (below).

http://www.geocities.com/zoomkat/RSswitcher.htm

 

[JeffM]

I did find...Unicorn Electronics

a good electronics store in New York City ?
BrianLunde

This'll get you started with catalogs:
http://www.google.com/search?&q=newark+allied+digikey+mouser+all-electronics+goldmine+b-g
Having dead-tree format references can often help you compare prices.
Google can be a help as can the search engines at the distributors'
sites.
(Warning: Newark's sucks.)

a good introduction to electronics and circuits without all the math ?

Graham Knott is a professional educator. Good site for basics:
http://homepage.ntlworld.com/g.knott/index1.htm

http://www.ibiblio.org/obp/electricCircuits/
This is part of an online library which is a collaboration between
the University of North Carolina-Chapel Hill
and the Center for the Public Domain.

The "bible" is *The Art of Electronics* by Paul Horowitz and Winfield
Hill.
(Win posts here regularly.) Your library may have a copy.
If this turns ito a passion, the ~$55 for the book (~$75 retail)
will be well spent. You'll refer back to it throughout your life.

As Seth said, don't be afraid of a little math.

 

[John Woodgate]

As Seth said, don't be afraid of a little math.

It can help to prevent an unwelcome aftermath. (;-)

 

[Rich Grise]

Oh, heavens! There's nothing to it!

Run the B channel output through a .1 cap to a 1N4148 cathode, its anode
to ground. Wire the junction to both a 10K resistor whose other end
is grounded, a 1N4148 anode whose cathode goes to +vcc, and the input
of a 74HC14 or so, schmitt trigger gate.

With the gate output, drive a transistor which pulls in a small
solenoid. This solenoid pulls a rachet arm which advances your
switch one space, providing power to the next LED in the sequence.

You can build the switch out of cardboard and thumbtacks.
You can wind a solenoid on the core of an adding machine tape.
This is how science fair projects win prizes. ;-) (or at least
they did a millennium ago %-/ )

Cheers!
Rich