led randomizer

[Jason Allen Finnigan]

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni

 

[Luhan Monat]

Jason Allen Finnigan wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni


PIC16F670 is about $3 and can drive about 22 LED's in any pattern you

want. It runs on 5 volts.

--
Luhan Monat, "LuhanKnows" At 'Yahoo' dot 'Com'
http://members.cox.net/berniekm
"The future is not what it used to be."

 

[Jem Berkes]

You could use shift registers to general random signals, or use a
counter with a prom/eprom - that way you could program custom
patterns, or just program random data into it.

Just to point out something about the term 'random'... it's going to be
pretty hard to actually generate a truly random sequence. But in a digital
circuit, you can use a shift register with various feedback (throw in some
kinds of XORs and other funky things) to generate a sequence that appears
random.

To get truly random, you'd have to tap into thermal effects or noise.
That's not worth the effort; it's better to go digital with a convoluted
sequence that appears random.

--
Jem Berkes
http://www.sysdesign.ca/

 

[Mark (UK)]

Hiya!

You could use shift registers to general random signals, or use a
counter with a prom/eprom - that way you could program custom patterns,
or just program random data into it.

Yours, Mark.

Jason Allen Finnigan wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni

 

[Dave]

In message <EEkKb.3929$LF6.2374@newssvr16.news.prodigy.com>, Jason Allen
Finnigan <finniganj@sbcglobal.net> expounds

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni


http://quozl.netrek.org/flasher/

--
--dave

news001@nospam.org.uk

 

[Wouter van Ooijen (www.vo]

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this

http://www.voti.nl/shop/products.html#K-KITT-1
(sorry for the slow page)

This is a kitt-display, but besides the classic kitt pattern it can
show a lot of other patterns, including random. Of course it uses a
LFSR for that, implemented in the PIC.
Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[Terry Pinnell]

"Jason Allen Finnigan" <finniganj@sbcglobal.net> wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni

i built a circuit to do this about 20 years ago and will try to find
its schematic when i have time later today but right now i recall it
used to appear entirely random but my priority first is to go out
shopping for a few more packs of periods

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[Bob Masta]

On 6 Jan 2004 01:07:54 GMT, Jem Berkes <jem@users.pc9__org> wrote:

You could use shift registers to general random signals, or use a
counter with a prom/eprom - that way you could program custom
patterns, or just program random data into it.

Just to point out something about the term 'random'... it's going to be
pretty hard to actually generate a truly random sequence. But in a digital
circuit, you can use a shift register with various feedback (throw in some
kinds of XORs and other funky things) to generate a sequence that appears
random.

To get truly random, you'd have to tap into thermal effects or noise.
That's not worth the effort; it's better to go digital with a convoluted
sequence that appears random.

--
Jem Berkes
http://www.sysdesign.ca/

Actually, it's pretty simple to get a true random source.
A reversed-biased transistor junction makes a good
white noise generator. Put about 100K from the collector
of an NPN to +9V or more, and ground the base. Take
the output from the collector through a capacitor to
block the DC, and use it to trigger a Schmitt trigger
or comparator.

This will give a random pulse pattern, but it will be
at a fairly high rate... too fast for LEDs. And if you
simply try to divide it down with flip-flops, it will come
closer and closer to a square wave the more stages
you use. You would need additional circuitry to get
random pulses at slow rates, so it might be simpler to
use the shift register pseudo-random approach with
a slow clock in the first place.



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[John Woodgate]

I read in sci.electronics.design that Bob Masta
<StopSpam@EveryChance.org> wrote (in <3ffab5de.2526677@news.itd.umich.ed
u&gt about 'led randomizer', on Tue, 6 Jan 2004:

Actually, it's pretty simple to get a true random source.
A reversed-biased transistor junction makes a good
white noise generator. Put about 100K from the collector
of an NPN to +9V or more, and ground the base. Take
the output from the collector through a capacitor to
block the DC, and use it to trigger a Schmitt trigger
or comparator.

The E-B junction is more usually used.

This will give a random pulse pattern, but it will be
at a fairly high rate... too fast for LEDs.

Just severely low-pass filter the noise signal from the transistor. You
lose a lot of signal level but an op-amp will make that up, either
before or after the filter, or both.


--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

 

[Terry Pinnell]

Terry Pinnell <terrypinDELETE@dial.pipexTHIS.com> wrote:

"Jason Allen Finnigan" <finniganj@sbcglobal.net> wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni


i built a circuit to do this about 20 years ago and will try to find
its schematic when i have time later today but right now i recall it
used to appear entirely random but my priority first is to go out
shopping for a few more packs of periods

Well, I found the full stops, but not the circuit. Best I can do is a
description.

A low frequency astable with a pot to vary its period typically has a
low of 10 ms and high 200mS. After inversion/buffering, each low gates
a TTL HF oscillator (about 24 MHz). Output from that in turn goes to 6
cascaded TTL flip-flops (binary dividers). So during the 10 mS low
time, about 24*.01*10^6 pulses are counted by the dividers. Q1 on
average changes about 120,000 times, Q2 60,000...and Q6 4,000 times.
In practice there is a random variation in the successive periods of
the astable, so the combination of 6 Q outputs effectively changes at
random, freezing when oscillation stops, then resuming again a short
time later. These drive coloured lamps via transistors.

Note that during oscillation the divider outputs are still changing,
but the time is so short this is not visible.

Additional divider outputs could be added, of course.

I also added a timer operated by a push button, so that instead of
constantly changing, the lamps changed to a new pattern only when
button was pressed. (It was a novelty toy for one of my two sons.)

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[Watson A.Name - "Watt Sun]

In article <8n0lvvgqd1uambu4e16tiqa7f4c61t9p8v@4ax.com>,
terrypinDELETE@dial.pipexTHIS.com mentioned...

"Jason Allen Finnigan" <finniganj@sbcglobal.net> wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni


i built a circuit to do this about 20 years ago and will try to find
its schematic when i have time later today but right now i recall it
used to appear entirely random but my priority first is to go out
shopping for a few more packs of periods

Yeah, Terry. I really dislike those who make it difficult to read
their posts. To the point where I don't even want to reply...


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

 

[Terry Pinnell]

Watson A.Name - "Watt Sun, Dark Remover" <alondra101@hotmail.com>
wrote:

In article <8n0lvvgqd1uambu4e16tiqa7f4c61t9p8v@4ax.com>,
terrypinDELETE@dial.pipexTHIS.com mentioned...
"Jason Allen Finnigan" <finniganj@sbcglobal.net> wrote:

alright here's what I am wanting to do I want to put leds of different
colors in the bezel of my computer case I want them to randomly flash and if
possible to be powered by the 5v output on my power supply I am not sure how
to do this if anyone has any ideas could you email me and let me know how I
could do this
thanks finni


i built a circuit to do this about 20 years ago and will try to find
its schematic when i have time later today but right now i recall it
used to appear entirely random but my priority first is to go out
shopping for a few more packs of periods

Yeah, Terry. I really dislike those who make it difficult to read
their posts. To the point where I don't even want to reply...

I wonder if poor writing can be correlated with poor manners? My reply
of 6th Jan hasn't so far had any response.

--
Terry Pinnell
Hobbyist, West Sussex, UK

 

[HaCv]

StopSpam@EveryChance.org (Bob Masta) wrote in message news:<3ffab5de.2526677@news.itd.umich.edu>...

On 6 Jan 2004 01:07:54 GMT, Jem Berkes <jem@users.pc9__org> wrote:

You could use shift registers to general random signals, or use a
counter with a prom/eprom - that way you could program custom
patterns, or just program random data into it.

Just to point out something about the term 'random'... it's going to be
pretty hard to actually generate a truly random sequence. But in a digital
circuit, you can use a shift register with various feedback (throw in some
kinds of XORs and other funky things) to generate a sequence that appears
random.

To get truly random, you'd have to tap into thermal effects or noise.
That's not worth the effort; it's better to go digital with a convoluted
sequence that appears random.

--
Jem Berkes
http://www.sysdesign.ca/


Actually, it's pretty simple to get a true random source.
A reversed-biased transistor junction makes a good
white noise generator. Put about 100K from the collector
of an NPN to +9V or more, and ground the base. Take
the output from the collector through a capacitor to
block the DC, and use it to trigger a Schmitt trigger
or comparator.

This will give a random pulse pattern

then send it to a pic's adc input and take the value of convertion to
drive the leds.... or a 4028 1-10 decoder...

, but it will be
at a fairly high rate... too fast for LEDs. And if you
simply try to divide it down with flip-flops, it will come
closer and closer to a square wave the more stages
you use. You would need additional circuitry to get
random pulses at slow rates, so it might be simpler to
use the shift register pseudo-random approach with
a slow clock in the first place.



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

 

[Terry Pinnell]

hecastil2@hotmail.com (HaCv) wrote:

StopSpam@EveryChance.org (Bob Masta) wrote in message news:<3ffab5de.2526677@news.itd.umich.edu>...
On 6 Jan 2004 01:07:54 GMT, Jem Berkes <jem@users.pc9__org> wrote:

You could use shift registers to general random signals, or use a
counter with a prom/eprom - that way you could program custom
patterns, or just program random data into it.

Just to point out something about the term 'random'... it's going to be
pretty hard to actually generate a truly random sequence. But in a digital
circuit, you can use a shift register with various feedback (throw in some
kinds of XORs and other funky things) to generate a sequence that appears
random.

To get truly random, you'd have to tap into thermal effects or noise.
That's not worth the effort; it's better to go digital with a convoluted
sequence that appears random.

--
Jem Berkes
http://www.sysdesign.ca/


Actually, it's pretty simple to get a true random source.
A reversed-biased transistor junction makes a good
white noise generator. Put about 100K from the collector
of an NPN to +9V or more, and ground the base. Take
the output from the collector through a capacitor to
block the DC, and use it to trigger a Schmitt trigger
or comparator.

This will give a random pulse pattern

then send it to a pic's adc input and take the value of convertion to
drive the leds.... or a 4028 1-10 decoder...

, but it will be
at a fairly high rate... too fast for LEDs. And if you
simply try to divide it down with flip-flops, it will come
closer and closer to a square wave the more stages
you use. You would need additional circuitry to get
random pulses at slow rates, so it might be simpler to
use the shift register pseudo-random approach with
a slow clock in the first place.



Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com

See my message up-thread
Message-ID: <u8u900tvbiner8itstbgteuqid1sm80j16@4ax.com>

--
Terry Pinnell
Hobbyist, West Sussex, UK