oscillating LED circuit - Electronic Circuits Projects Diagrams Free

daviddoria · 20th February 2003, 02:13 AM

SCHOOL PHYSICS PROJECT

i made a cool thing for my computer, seen here: http://www.bandtank.com/stuff/movies/MVI_1646.AVI

its just a 555 timer that is speed controlled by a 100k pot (i think i got the diagram from this forum!)

i was wonder how to make this into something that would make the LEDs "run" back and forth instead of blink 4 at a time.

can anyone give me any input on this?

i got a reply about using a decade counter... not sure how to do this though. I have an NTE74192 right here if its possible to use that...

any input would be great!

thanks
david

john1 · 20th February 2003, 03:12 AM

Has anybody been able to successfully download this ?

**kinjalgp** · 20th February 2003, 10:39 AM

Yes I have

arcom · 20th February 2003, 10:55 AM

Me too 8)

john1 · 20th February 2003, 06:17 PM

well i dont know ...

What is it anyway?

**kinjalgp** · 20th February 2003, 07:26 PM

Use combination of two 4017 decade counters to achieve up-down running effect.

arcom · 20th February 2003, 07:33 PM

to john1: It's just a small movie showing flashing LEDs placed in an unused 5,25" bay on a computer case...

daviddoria · 20th February 2003, 10:07 PM

haha kinjalgp thats what you said in the other forum too hehe.
as you have probably gathered i am new to this stuff, so i was really looking for some tutorial on counter or an example circuit of some sort.

anyone?

david

**kinjalgp** · 21st February 2003, 01:42 AM

Check this page: http://control.gsnu.ac.kr/~f007dan/cicuit/page5.htm

daviddoria · 23rd February 2003, 01:24 PM

page cannot be found.

hmmm
can you retype the link?

**kinjalgp** · 23rd February 2003, 04:33 PM

Try this ones:
http://ourworld.compuserve.com/homep...wden/page5.htm
http://www.qsl.net/yo5ofh/hobby%20ci...d_circuits.htm

daviddoria · 24th February 2003, 04:24 PM

i decided to use this schematic

http://www.bandtank.com/~calculusap/leds.gif

it says the NPN transistors increase the current to 20ma. what is the current coming out of chip without the transistor?

also, what does the 120 resistor do? like what is coming out of pins 2 and 6 of the 555?

**kinjalgp** · 24th February 2003, 05:07 PM

The 120 Ohm resistor limits the current flowing through LEDs otherwise they will burn out.
The current sourcing capacity of HCF4017 (SGS Thomson make) is typically 2mA per output.

Gene · 24th February 2003, 05:18 PM

David - The schematic you have selected seems too complex (all those transistors) for what it does. But, the reason for the note is that your circuit will light the LEDs in order (1 - 10) and then repeat the sequence. This was not the way I understood your original question. I thought you wanted the LEDs to run back and forth. If you are still interested, here is a simple little circuit:

http://www.andy-clarkson.me.uk/555/projects.html

**kinjalgp** · 24th February 2003, 05:34 PM

Hi Gene,
I doub't whether the given "Knight Rider Lights" circuit on the site will produce the reverse effect because the counter IC seems to be doing only the up-counting whereas you require another 4017 for reverse effect.

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20th February 2003, 02:13 AM	(permalink)
daviddoria	oscillating LED circuit SCHOOL PHYSICS PROJECT i made a cool thing for my computer, seen here: http://www.bandtank.com/stuff/movies/MVI_1646.AVI its just a 555 timer that is speed controlled by a 100k pot (i think i got the diagram from this forum!) i was wonder how to make this into something that would make the LEDs "run" back and forth instead of blink 4 at a time. can anyone give me any input on this? i got a reply about using a decade counter... not sure how to do this though. I have an NTE74192 right here if its possible to use that... any input would be great! thanks david __________________ thanks, david

20th February 2003, 10:39 AM	(permalink)
kinjalgp	Yes I have __________________ "There is no way to peace, peace is the way!"

20th February 2003, 06:17 PM	(permalink)
john1	well i dont know ... What is it anyway?

20th February 2003, 07:26 PM	(permalink)
kinjalgp	Use combination of two 4017 decade counters to achieve up-down running effect. __________________ "There is no way to peace, peace is the way!"

20th February 2003, 07:33 PM	(permalink)
arcom	to john1: It's just a small movie showing flashing LEDs placed in an unused 5,25" bay on a computer case...

20th February 2003, 10:07 PM	(permalink)
daviddoria	haha kinjalgp thats what you said in the other forum too hehe. as you have probably gathered i am new to this stuff, so i was really looking for some tutorial on counter or an example circuit of some sort. anyone? david __________________ thanks, david

21st February 2003, 01:42 AM	(permalink)
kinjalgp	Check this page: http://control.gsnu.ac.kr/~f007dan/cicuit/page5.htm __________________ "There is no way to peace, peace is the way!"

23rd February 2003, 01:24 PM	(permalink)
daviddoria	page cannot be found. hmmm can you retype the link? __________________ thanks, david

23rd February 2003, 04:33 PM	(permalink)
kinjalgp	Try this ones: http://ourworld.compuserve.com/homep...wden/page5.htm http://www.qsl.net/yo5ofh/hobby%20ci...d_circuits.htm __________________ "There is no way to peace, peace is the way!"

24th February 2003, 04:24 PM	(permalink)
daviddoria	i decided to use this schematic http://www.bandtank.com/~calculusap/leds.gif it says the NPN transistors increase the current to 20ma. what is the current coming out of chip without the transistor? also, what does the 120 resistor do? like what is coming out of pins 2 and 6 of the 555? __________________ thanks, david

24th February 2003, 05:07 PM	(permalink)
kinjalgp	The 120 Ohm resistor limits the current flowing through LEDs otherwise they will burn out. The current sourcing capacity of HCF4017 (SGS Thomson make) is typically 2mA per output. __________________ "There is no way to peace, peace is the way!"

24th February 2003, 05:18 PM	(permalink)
Gene	David - The schematic you have selected seems too complex (all those transistors) for what it does. But, the reason for the note is that your circuit will light the LEDs in order (1 - 10) and then repeat the sequence. This was not the way I understood your original question. I thought you wanted the LEDs to run back and forth. If you are still interested, here is a simple little circuit: http://www.andy-clarkson.me.uk/555/projects.html

24th February 2003, 05:34 PM	(permalink)
kinjalgp	Hi Gene, I doub't whether the given "Knight Rider Lights" circuit on the site will produce the reverse effect because the counter IC seems to be doing only the up-counting whereas you require another 4017 for reverse effect. __________________ "There is no way to peace, peace is the way!"