Y
Yaron
Guest
I just wanted to know how
can I generate a precise 1 hertz clock pulse.
can I generate a precise 1 hertz clock pulse.
A
Anthony Fremont
Guest
"Yaron" <fire_wall4@yahoo.com> wrote:
limits like accuracy, cost, size, power requirements etc. If you need
an extremely "precise" 1hz clock, use a GPS receiver. If "wall clock"
accuracy is your goal use a crystal based oscillator or maybe hack a
cheap quartz clock module. If you're cooking eggs, use a RC based
circuit like 555 timer. ;-)
michael
It all depends upon your definition of precise. You need to state some
limits like accuracy, cost, size, power requirements etc. If you need
an extremely "precise" 1hz clock, use a GPS receiver. If "wall clock"
accuracy is your goal use a crystal based oscillator or maybe hack a
cheap quartz clock module. If you're cooking eggs, use a RC based
circuit like 555 timer. ;-)
michael
D
Don Bruder
Guest
In article <3f8bebce$1@news.012.net.il>, "Yaron" <fire_wall4@yahoo.com>
wrote:
Use a 74HCU04, two caps, two resistors, and a known-value crystal.
(Somebdy please refresh my memory on the name for this type of
oscillator? I think it starts with "F", but I'm not sure.)
Feed the output to circuitry that behaves as a "divide by <crystal
frequency> counter", and take your 1 Hz signal off of the output from
that. You may want to feed it to a schmidtt trigger to be sure it's nice
and clean before actually putting it to work, but I'd consider that an
optional improvement. Presto. Crystal accurate 1 Hz oscillator
--
Don Bruder - dakidd@sonic.net <--- Preferred Email - SpamAssassinated.
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wrote:
Use a 74HCU04, two caps, two resistors, and a known-value crystal.
(Somebdy please refresh my memory on the name for this type of
oscillator? I think it starts with "F", but I'm not sure.)
Feed the output to circuitry that behaves as a "divide by <crystal
frequency> counter", and take your 1 Hz signal off of the output from
that. You may want to feed it to a schmidtt trigger to be sure it's nice
and clean before actually putting it to work, but I'd consider that an
optional improvement. Presto. Crystal accurate 1 Hz oscillator
--
Don Bruder - dakidd@sonic.net <--- Preferred Email - SpamAssassinated.
Hate SPAM? See <http://www.spamassassin.org> for some seriously great info.
I will choose a path that's clear: I will choose Free Will! - N. Peart
Fly trap info pages: <http://www.sonic.net/~dakidd/Horses/FlyTrap/index.html>
J
John Larkin
Guest
On Tue, 14 Oct 2003 15:29:30 +0200, "Yaron" <fire_wall4@yahoo.com>
wrote:
motor drive pulses.
John
wrote:
Buy a cheap mechanical-dial quartz clock and tap into the stepper
motor drive pulses.
John
C
Costas Vlachos
Guest
"Yaron" <fire_wall4@yahoo.com> wrote in message
news:3f8bebce$1@news.012.net.il...
You can use a 32.768 kHz crystal oscillator, and then divide that frequency
using a 15-bit binary counter. The crystal's frequency value is a power of
2, so the division will be perfect and you'll end up with an accurate and
precise 1 Hz square wave. The crystal is cheap and easy to find, as it is
commonly used in digital watches.
Or, you could use a small microcontroller (with a crystal oscillator) and
generate the pulse with code. This could well be the easiest solution (only
one IC required), depending on how familiar you are with MCUs.
Check this link for more info:
http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#counter.gif
HTH
Costas
news:3f8bebce$1@news.012.net.il...
You can use a 32.768 kHz crystal oscillator, and then divide that frequency
using a 15-bit binary counter. The crystal's frequency value is a power of
2, so the division will be perfect and you'll end up with an accurate and
precise 1 Hz square wave. The crystal is cheap and easy to find, as it is
commonly used in digital watches.
Or, you could use a small microcontroller (with a crystal oscillator) and
generate the pulse with code. This could well be the easiest solution (only
one IC required), depending on how familiar you are with MCUs.
Check this link for more info:
http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#counter.gif
HTH
Costas
T
Tom Woodrow
Guest
http://www.elmelectronics.com/ebench.html
Tom Woodrow
www.dacworks.com
Yaron wrote:
Tom Woodrow
www.dacworks.com
Yaron wrote:
B
Bill Bowden
Guest
"Yaron" <fire_wall4@yahoo.com> wrote in message news:<3f8bebce$1@news.012.net.il>...
http://ourworld.compuserve.com/homepages/Bill_Bowden/dclock.htm
It uses a 32768 Hz watch crystal and a 4020, 14 stage counter
to get 2 Hz. The 2 hertz signal is divided by 2 to get a
1 Hz square wave out of the 4013 flip flop.
There is also another clock circuit that divides the 60 Hz line
frequency down to 1 Hz. but you need almost as many parts either
way.
-Bill
There is digital clock circuit with a 1 Hz generator at :
http://ourworld.compuserve.com/homepages/Bill_Bowden/dclock.htm
It uses a 32768 Hz watch crystal and a 4020, 14 stage counter
to get 2 Hz. The 2 hertz signal is divided by 2 to get a
1 Hz square wave out of the 4013 flip flop.
There is also another clock circuit that divides the 60 Hz line
frequency down to 1 Hz. but you need almost as many parts either
way.
-Bill