One Second Pulse-Width, Once Per Hour

[Rich Grise]

Here's a crazy idea for a one-second pulse, once an hour:

Take an ordinary wall clock, the kind with hands.
Drill 5 little holes in the face; one that will be
blocked once an hour by the hour hand, two that
will be blocked by the minute hand one minute apart,
and two that will be blocked by the second hand one
second apart.

lessee, (I'm inventing as I go along) you'd have the
two second-hand photodiodes go to the R and S input
of your pulse generator; this is gated by the Q
output of another RS FF controlled by the minutes
PHDs, and this would all get fired once by the
trigger from the hour hand PHD.

The details, of course, are left as an exercise for
the reader. ?;->

Cheers!
Rich

 

[Mjolinor]

"Rich Grise" <null@example.net> wrote in message
news:ZiFcc.5635$bd4.1179@nwrddc01.gnilink.net...

Here's a crazy idea for a one-second pulse, once an hour:

Take an ordinary wall clock, the kind with hands.
Drill 5 little holes in the face; one that will be
blocked once an hour by the hour hand, two that
will be blocked by the minute hand one minute apart,
and two that will be blocked by the second hand one
second apart.

lessee, (I'm inventing as I go along) you'd have the
two second-hand photodiodes go to the R and S input
of your pulse generator; this is gated by the Q
output of another RS FF controlled by the minutes
PHDs, and this would all get fired once by the
trigger from the hour hand PHD.

The details, of course, are left as an exercise for
the reader. ?;-

Cheers!
Rich

You should get out more and why do you have to use second hand photo diodes?
Will new ones not work in this design?

 

[Bill Garber]

"Rich Grise" <null@example.net> wrote in message
news:ZiFcc.5635$bd4.1179@nwrddc01.gnilink.net...
: Here's a crazy idea for a one-second pulse, once an hour:
:
: Take an ordinary wall clock, the kind with hands.
: Drill 5 little holes in the face; one that will be
: blocked once an hour by the hour hand, two that
: will be blocked by the minute hand one minute apart,
: and two that will be blocked by the second hand one
: second apart.
:
: lessee, (I'm inventing as I go along) you'd have the
: two second-hand photodiodes go to the R and S input
: of your pulse generator; this is gated by the Q
: output of another RS FF controlled by the minutes
: PHDs, and this would all get fired once by the
: trigger from the hour hand PHD.

I'll suggest this once more and see where it goes.
What about a digital alarm clock? Each time the hour
ticks, run the pulse until the seconds tick. Restart
and wait for the hour to tick again. As with other
suggestions, the method to accomplish this is up to
the reader.

Bill @ GarberStreet Enterprizez };-)
Web Site - http://garberstreet.netfirms.com
Email - willy46pa @ comcast DOT net
Change DOT to a dot to contact me



---
This email ain't infected, dude!

Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.634 / Virus Database: 406 - Release Date: 3/22/04

 

[John Fields]

On Tue, 06 Apr 2004 21:29:29 GMT, "Rich Grise" <null@example.net>
wrote:

Here's a crazy idea for a one-second pulse, once an hour:

Take an ordinary wall clock, the kind with hands.
Drill 5 little holes in the face; one that will be
blocked once an hour by the hour hand, two that
will be blocked by the minute hand one minute apart,
and two that will be blocked by the second hand one
second apart.

lessee, (I'm inventing as I go along) you'd have the
two second-hand photodiodes go to the R and S input
of your pulse generator; this is gated by the Q
output of another RS FF controlled by the minutes
PHDs, and this would all get fired once by the
trigger from the hour hand PHD.

The details, of course, are left as an exercise for
the reader. ?;-

---
Good thing too, since it seems a few details have escaped you.

First of all, every time the second hand goes around it'll go by the
seconds LDRs, bit it'll also go by the minutes and hours LDRs.

Second, when the minute hand goes around it'll go by the minutes LDRs,
but it'll also go by the hours LDR (and the seconds LDRs if the minute
hand is long enough.

Third, the hour hand would only go by the hours LDR once every 12
hours, but the minute hand would go past it once per hour and the
second hand would go by it once a minute, so it seems like your
"invention" needs some more work. Not just with the timekeeping
either, you need to provide some means for the thing to work in the
dark.

Here's how I'd do it for use in total darkness:

1. Radially drill three small holes in the clock face, (out past the
reach of the hour hand) one at precisely 12:00, one at 12:01, and one
at 12:02. make sure the diameter of the 12:00 hole is 3° or less.

2. Glue a betalight with an output around 500nm to the under surface
of the minute hand and mask it with a 3° aperture such that the
aperture lines up with the 12:00 hole.

3. Place an LDR behind the 12:00 hole with a spectral sensitivity
which matches the output of the betalight.

4. Behind the 12:01 and 12:02 holes, place a reflective object IR
photosensor, and make sure the back of the second hand reflects IR.


Now, when the minute hand goes by 12:00, the betalight will cause the
green responding LDR's resistance to drop, which will turn on the
reflective sensors' IRLEDS. When the second hand goes by the 12:01
hole the beam from the IRLED will bounce off of it and reflect back to
the IR phototransistor, turning on a latch, starting the 1 second
pulse. When the second hand goes by the 12:01 hole it'll reset the
latch, turning off the pulse and the IRLEDs, since they won't be
needed for another hour.

How to do it in daylight is left as an exercise for the student

--
John Fields

 

[Rich Grise]

"John Fields" <jfields@austininstruments.com> wrote in message
news:3vh870hclbdvkif9asebbd20m911v8onv8@4ax.com...

On Tue, 06 Apr 2004 21:29:29 GMT, "Rich Grise" <null@example.net
Here's a crazy idea for a one-second pulse, once an hour:
....
The details, of course, are left as an exercise for
the reader. ?;-

---
Good thing too, since it seems a few details have escaped you.

Oh, they didn't escape - i was never trying to hold them
prisoner. ;-)

Here's how I'd do it for use in total darkness:

Well, there ya go - leaving it open _was_ a good idea then!

1. Radially drill three small holes in the clock face, (out past the
reach of the hour hand) one at precisely 12:00, one at 12:01, and one
at 12:02. make sure the diameter of the 12:00 hole is 3° or less.

2. Glue a betalight with an output around 500nm to the under surface
of the minute hand and mask it with a 3° aperture such that the
aperture lines up with the 12:00 hole.

3. Place an LDR behind the 12:00 hole with a spectral sensitivity
which matches the output of the betalight.

4. Behind the 12:01 and 12:02 holes, place a reflective object IR
photosensor, and make sure the back of the second hand reflects IR.


Now, when the minute hand goes by 12:00, the betalight will cause the
green responding LDR's resistance to drop, which will turn on the
reflective sensors' IRLEDS. When the second hand goes by the 12:01
hole the beam from the IRLED will bounce off of it and reflect back to
the IR phototransistor, turning on a latch, starting the 1 second
pulse. When the second hand goes by the 12:01 hole it'll reset the
latch, turning off the pulse and the IRLEDs, since they won't be
needed for another hour.

How to do it in daylight is left as an exercise for the student

--
John Fields

 

[The Real Andy]

"Rich Grise" <null@example.net> wrote in message
news:3K7dc.11566$hd3.386@nwrddc03.gnilink.net...

"John Fields" <jfields@austininstruments.com> wrote in message

Here is what I would do.

Get an ordinary wall clock. Cut off the second hand, and the hour hand.
Drill a hole anywhere in the clock where the minute hand passes and not to
close to the centre. Use an led/lamp and phototransistor/ldr combination.
Place the detection device behind the hole, and the emitting device on the
other side of the hole with enough room for the minute hand to pass between.
Connect the detector to one of those dreaded 555 in a monostable
configuration. Bung the whole lot into a shoe box and whala (or however you
spell it) a timer as per spec.

Alternatively (I have read any other posts yet) you could just use a dual
dreaded 555.

 

[John Fields]

On Thu, 08 Apr 2004 08:06:23 GMT, "Rich Grise" <null@example.net>
wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:3vh870hclbdvkif9asebbd20m911v8onv8@4ax.com...
On Tue, 06 Apr 2004 21:29:29 GMT, "Rich Grise" <null@example.net
Here's a crazy idea for a one-second pulse, once an hour:
...
The details, of course, are left as an exercise for
the reader. ?;-

---
Good thing too, since it seems a few details have escaped you.

Oh, they didn't escape - i was never trying to hold them
prisoner. ;-)

---
How could you? You never even caught them!^)
---


--
John Fields

 

[Mjolinor]

"John Fields" <jfields@austininstruments.com> wrote in message
news:77pa70lka0cfu6bpjjv52qpduv8gcko3or@4ax.com...

On Thu, 08 Apr 2004 08:06:23 GMT, "Rich Grise" <null@example.net
wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:3vh870hclbdvkif9asebbd20m911v8onv8@4ax.com...
On Tue, 06 Apr 2004 21:29:29 GMT, "Rich Grise" <null@example.net
Here's a crazy idea for a one-second pulse, once an hour:
...
The details, of course, are left as an exercise for
the reader. ?;-

---
Good thing too, since it seems a few details have escaped you.

Oh, they didn't escape - i was never trying to hold them
prisoner. ;-)

---
How could you? You never even caught them!^)
---

Real slimy creatures are details, you think you have them all and then
realise they were fooling you and some of them sacrifice themself in order
that some may escape. Definate hierachy in their behaviour where the most
damaging ones are protected by the non fatal / non explosive/ non
embarrasing type. They come in all shapes and sizes and as a species are
most difficult to recognise.