The cheapest way to blink a led

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A comment in another thread got me thinking - what is the cheapest way to
blink a led these days?

It's a hard question to answer and depends on volume I suspect allot.   I
suspect that a required duty cycle would also figure quite heavily into the
cost also.  But removing making your own silicon, and taking into count, PCB
cost and Component placement - is a uController now cheaper than a couple of
transistors + a few C's & R's?

Anyone have any really simple low cost way to do it? One of the Tiny Logic
packages?

Ralph



Re: The cheapest way to blink a led
Buy a Blink-LED. That's all!
- Henry

Ralph Mason schrieb in Nachricht ...
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PCB
of



Re: The cheapest way to blink a led
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I suppose a blinking LED just wouldn't do the job?  (*Someone* had to
ask.)

--
Ron Sharp.



Re: The cheapest way to blink a led
On Sat, 25 Oct 2003 11:59:22 +1300, "Ralph Mason"

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A flashing LED should do the trick :)

Farnell - part number 515-723, Oz$0.55 each per 100

Mike Harding


Re: The cheapest way to blink a led



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Cheaper still, get a grab bag of LEDs, about 3c each LED then open and
close your eyes quickly.

Al


Re: The cheapest way to blink a led
masonralph_at_yahoo_dot_ snipped-for-privacy@thisisnotarealaddress.com says...
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If you really just want a cheap blinking LED,  buy a blinking LED!
The only external part will be a current limiting resistor.  Can't
get much cheaper than that!

Mark Borgerson



Re: The cheapest way to blink a led

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Nope, not even an external resistor is needed; which is
a blinking good job :)

Mike Harding


Re: The cheapest way to blink a led

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to
I
the
count, PCB
couple of
Logic

You can add some other non-blinking LEDs in series with the blinking LED and
they all become blinking LEDs all at the same blinknig rate.



Re: The cheapest way to blink a led

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Blinking hell! I didn't know that!

Mike Harding

(Must be 35+ years since I heard "blinking" used as a
profanity - perhaps we haven't advanced all that much? :)


Re: The cheapest way to blink a led
Rob said for all posterity...

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I had a flashback to "Airplane II - The Sequel":

"Sir, these lights keep blinking out of sequence.  What should we
do?"
"Get them to blink in sequence."   (William Shatner)
"Yes sir!".




Casey


Re: The cheapest way to blink a led

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way
into
and

Yep.  My brother got invited to this black tie bash back in the lat 1970s,
and he wanted to do something "different".  He came to me with the request
about an hour or two before his date was picking him up.  Luckily, I had a
blinking LED in my junkbox.  Luckily, HE had a camera flash NiCd pack that
provided an acceptable voltage for the blinking LED and two series LEDs.  I
don't remember now if I already knew the blinking LED could be used that way
or if I tried it on the spur of the moment and it worked.



Re: The cheapest way to blink a led
On Sat, 25 Oct 2003 11:59:22 +1300, the renowned "Ralph Mason"

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A flashing LED- there's a die inside in series with the LED chip. No
other parts.

Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
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Re: The cheapest way to blink a led

    Previous respondants have it right, if you just want a ~50% duty cycle
use a blinking LED.  However if you want anything else, or are anxious to
use a microcontroller, consider the Cygnal C8051F305 which is only $0.99
each.  2k of flash in a 3mm package and with judicious programming (sleep
mode) it sucks essentially zero current.  Kind of a waste but the cheapest
uc solution I can think of unless you're in huge quantities.

    Heck, you could even have is send out morse messages!

--Albert

On Sat, 25 Oct 2003 11:59:22 +1300, Ralph Mason wrote:

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-- Regards, Albert
----------------------------------------------------------------------
AM Research, Inc.                  The Embedded Systems Experts
http://www.amresearch.com (916) 780-7623
----------------------------------------------------------------------


Re: The cheapest way to blink a led
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what about those often bogus LEDS that blink in cars. They have a short duty
cycle. Are they blink-leds too?

Meindert



Re: The cheapest way to blink a led
On Sun, 26 Oct 2003 23:46:17 -0800, the renowned Albert Lee Mitchell

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What quantity is it supposed to be $0.99 in? Digikey sells them for
$2.55 in 100's, whereas a PIC12C508 is $0.96 in the same quantity. A
boring old LM555 is less than $0.25 in 100's, and half that in 1K.  

Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
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Re: The cheapest way to blink a led
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A boring old LM3909 would be a better solution than a 555, probably same
price range.

I had no idea that the bottom end uCs were so cheap now.  Perhaps I'll buy
a small jar of them and label it "Whatever".  :^)

--
Ron Sharp.



Re: The cheapest way to blink a led
On Mon, 27 Oct 2003 09:46:44 -0500, the renowned "Android Cat"

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Not really, as that part was discontinued half a decade ago... those
with NOS are probably rather proud of it.


Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
We've slightly trimmed the long signature. Click to see the full one.
Re: The cheapest way to blink a led
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Oh yeah...  What on Earth do all the electronics magazines use for bicycle
blinky-light projects then?  (Tesla coils, lie detectors, bicycle
blinky-lights = 75% of the project content.)  They could use a uC, but I'd
worry that someone would include a "black-box" data recorder as part of
the design.  (Kidding.  Ones for cars are in the news here, and everyone
is Shocked and Surprised.)

--
Ron Sharp.
Good thing I stockpiled those CK722s!



Re: The cheapest way to blink a led

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    As I said, _each_, quantity one, $0.99.  I have no idea how much Digikey
marks them up, you can purchase directly from Cygnal with a credit card.
Here's pricing:  http://www.cygnal.com/products/guide/default.asp I don't
thin there is a PIC for under a buck quantity one.

    As to using a 'boring old LM55', remember that you have to add a few
external components, the duty cycle is not very controllable without a
handfull of extra parts.  Even then you have to change h/w to change
frequency or duty cycle.  Using a micro gives a lot more options.

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-- Regards, Albert
----------------------------------------------------------------------
AM Research, Inc.                  The Embedded Systems Experts
http://www.amresearch.com (916) 780-7623
----------------------------------------------------------------------


Re: The cheapest way to blink a led
On Tue, 28 Oct 2003 00:45:53 -0800, the renowned Albert Lee Mitchell

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No, you did not say "quantity one". You merely said "each", which is
probably correct (in some quantity).

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Unh, that page says the 10,000 quantity price is $0.99 each. When I
add one to the shopping cart I get $4.46 US each. At 100 pieces the
price drops to $255/100 = $2.55 each. That is in line with Digikey's
price, as it darn well ought to be.

If you know a way to get the Cygnal parts in qty. 1 for the 10K price,
I'd like to know, I'm planning to use the C8051F123 in a low-volume
project and $12 would be better than $33 US each.

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Not for just anybody, anyhow.

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Not true, you can get any duty cycle you like with the same 2
resistors and a cap you need for astable operation. Plus one series
resistor for the LED which you'd need anyway. And it can drive a lot
of current and stay within spec.

Also the Cygnal parts will operate from 2.7 to 3.6V supply voltage,
whereas a 555 will operate from as much as 16V supply voltage (and
down to about 1V for some versions). The maximum 3.6V supply voltage
means that you can't directly drive a blue LED from the Cygnal part
without extra circuitry.

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True. Three fast blinks and a pause, for example.

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Best regards,
Spehro Pefhany
--
"it's the network..."                          "The Journey is the reward"
snipped-for-privacy@interlog.com             Info for manufacturers: http://www.trexon.com
We've slightly trimmed the long signature. Click to see the full one.

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