Infrared emitter and detector pair

On Feb 17, 2:58 pm, John Fields <jfie...@austininstruments.com> wrote:
On Thu, 17 Feb 2011 06:11:55 -0800 (PST), George Herold





gher...@teachspin.com> wrote:
On Feb 17, 7:38 am, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 16 Feb 2011 12:23:18 -0800 (PST), George Herold

gher...@teachspin.com> wrote:
I'm sure you can get the IR source->mirror->photodiode to work. I'm
not sure I'd want to mount it on a IC motor and expect it to stay
aligned with all the vibration.

How 'bout something else... surely there's lots of ways to sense the
RPM of a motor. Can you pick off a signal that does the spark
timing? Maybe a coil wrapped about the spark plug wire?

George H.

---
As a capacitive pick-off?

---
JF

No, I was thinking about sensing the current in the coil.... But
better to work on the primary side as Whit3rd suggested.  Too much
worry about getting 'whacked' by the HV.

---
You can't sense the current in a conductor by wrapping a coil of wire
around it.

---
JF- Hide quoted text -

- Show quoted text -
Click to expand...
Oh, does it need to be a torriod?
Thanks for the correction.

George H.
 
George Herold a écrit :
On Feb 17, 2:58 pm, John Fields <jfie...@austininstruments.com> wrote:
On Thu, 17 Feb 2011 06:11:55 -0800 (PST), George Herold





gher...@teachspin.com> wrote:
On Feb 17, 7:38 am, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 16 Feb 2011 12:23:18 -0800 (PST), George Herold
gher...@teachspin.com> wrote:
I'm sure you can get the IR source->mirror->photodiode to work. I'm
not sure I'd want to mount it on a IC motor and expect it to stay
aligned with all the vibration.
How 'bout something else... surely there's lots of ways to sense the
RPM of a motor. Can you pick off a signal that does the spark
timing? Maybe a coil wrapped about the spark plug wire?
George H.
---
As a capacitive pick-off?
---
JF
No, I was thinking about sensing the current in the coil.... But
better to work on the primary side as Whit3rd suggested. Too much
worry about getting 'whacked' by the HV.
---
You can't sense the current in a conductor by wrapping a coil of wire
around it.

---
JF- Hide quoted text -

- Show quoted text -

Oh, does it need to be a torriod?
Click to expand...
Yup. Lookup Rogowski coils.



--
Thanks,
Fred.
 
On Thu, 17 Feb 2011 19:33:59 -0800 (PST), George Herold
<gherold@teachspin.com> wrote:

On Feb 17, 2:58 pm, John Fields <jfie...@austininstruments.com> wrote:
On Thu, 17 Feb 2011 06:11:55 -0800 (PST), George Herold





gher...@teachspin.com> wrote:
On Feb 17, 7:38 am, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 16 Feb 2011 12:23:18 -0800 (PST), George Herold

gher...@teachspin.com> wrote:
I'm sure you can get the IR source->mirror->photodiode to work. I'm
not sure I'd want to mount it on a IC motor and expect it to stay
aligned with all the vibration.

How 'bout something else... surely there's lots of ways to sense the
RPM of a motor. Can you pick off a signal that does the spark
timing? Maybe a coil wrapped about the spark plug wire?

George H.

---
As a capacitive pick-off?

---
JF

No, I was thinking about sensing the current in the coil.... But
better to work on the primary side as Whit3rd suggested.  Too much
worry about getting 'whacked' by the HV.

---
You can't sense the current in a conductor by wrapping a coil of wire
around it.

---
JF- Hide quoted text -

- Show quoted text -

Oh, does it need to be a torriod?
Thanks for the correction.

George H.
Click to expand...
---
Nope, a toroid. ;)

---
JF
 
Fred Bartoli wrote:
George Herold a écrit :
On Feb 17, 2:58 pm, John Fields <jfie...@austininstruments.com> wrote:
On Thu, 17 Feb 2011 06:11:55 -0800 (PST), George Herold





gher...@teachspin.com> wrote:
On Feb 17, 7:38 am, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 16 Feb 2011 12:23:18 -0800 (PST), George Herold
gher...@teachspin.com> wrote:
I'm sure you can get the IR source->mirror->photodiode to work. I'm
not sure I'd want to mount it on a IC motor and expect it to stay
aligned with all the vibration.
How 'bout something else... surely there's lots of ways to sense the
RPM of a motor. Can you pick off a signal that does the spark
timing? Maybe a coil wrapped about the spark plug wire?
George H.
---
As a capacitive pick-off?
---
JF
No, I was thinking about sensing the current in the coil.... But
better to work on the primary side as Whit3rd suggested. Too much
worry about getting 'whacked' by the HV.
---
You can't sense the current in a conductor by wrapping a coil of wire
around it.

---
JF- Hide quoted text -

- Show quoted text -

Oh, does it need to be a torriod?

Yup. Lookup Rogowski coils.
Click to expand...
Or spiral.
http://en.wikipedia.org/wiki/Rogowski_coil

--Winston
 
krw@att.bizzzzzzzzzzzz wrote:
On Wed, 16 Feb 2011 18:29:01 -0800, Rich Grise<richg@example.net.invalid
wrote:

John Fields wrote:

sprinkled with oregano and drizzled with extra virgin olive oil for
dinner, so I can't help with that search right now. :-(

How is "extra virgin" olive oil different from plain ol' ordinary
everyday olive oil, other than the price?

"Virgin" means that it's olive oil (no chemicals added). "Extra-virgin" means
it's from the "first pressing" of the olives and is supposed to be better.
Neither of these terms have any legal meaning and the meaning words, if not
the oil, are often adulterated.
Click to expand...
It means that it's green and putrid-tasting. You have to add balsamic
vinegar to cut the taste, and then put it over bad-tasting 'baby greens'
to make a modern salad. Ain't progress wonderful. :(

Cheers

Phil "plain lettuce forever" Hobbs


--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
 
George Herold wrote:
On Feb 18, 10:31 am, Phil Hobbs
pcdhSpamMeSensel...@electrooptical.net> wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Wed, 16 Feb 2011 18:29:01 -0800, Rich Grise<ri...@example.net.invalid
wrote:

John Fields wrote:

sprinkled with oregano and drizzled with extra virgin olive oil for
dinner, so I can't help with that search right now. :-(

How is "extra virgin" olive oil different from plain ol' ordinary
everyday olive oil, other than the price?

"Virgin" means that it's olive oil (no chemicals added). "Extra-virgin" means
it's from the "first pressing" of the olives and is supposed to be better.
Neither of these terms have any legal meaning and the meaning words, if not
the oil, are often adulterated.

It means that it's green and putrid-tasting. You have to add balsamic
vinegar to cut the taste, and then put it over bad-tasting 'baby greens'
to make a modern salad. Ain't progress wonderful. :(n

Cheers

Phil "plain lettuce forever" Hobbs

Oh, Honeymoon salad?

"Lettuce alone, undressed."

George H.
Click to expand...
:)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) net
http://electrooptical.net
 
On Feb 18, 10:31 am, Phil Hobbs
<pcdhSpamMeSensel...@electrooptical.net> wrote:
k...@att.bizzzzzzzzzzzz wrote:
On Wed, 16 Feb 2011 18:29:01 -0800, Rich Grise<ri...@example.net.invalid
wrote:

John Fields wrote:

sprinkled with oregano and drizzled with extra virgin olive oil for
dinner, so I can't help with that search right now. :-(

How is "extra virgin" olive oil different from plain ol' ordinary
everyday olive oil, other than the price?

"Virgin" means that it's olive oil (no chemicals added).  "Extra-virgin" means
it's from the "first pressing" of the olives and is supposed to be better.
Neither of these terms have any legal meaning and the meaning words, if not
the oil, are often adulterated.

It means that it's green and putrid-tasting.  You have to add balsamic
vinegar to cut the taste, and then put it over bad-tasting 'baby greens'
to make a modern salad.  Ain't progress wonderful. :(

Cheers

Phil "plain lettuce forever" Hobbs
Click to expand...
Oh, Honeymoon salad?

"Lettuce alone, undressed."

George H.
--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058

email: hobbs (atsign) electrooptical (period) nethttp://electrooptical.net- Hide quoted text -

- Show quoted text -
Click to expand...
 
George Herold wrote:
On Feb 18, 10:31 am, Phil Hobbs
k...@att.bizzzzzzzzzzzz wrote:
On Wed, 16 Feb 2011 18:29:01 -0800, Rich
Grise<ri...@example.net.invalid> wrote:
John Fields wrote:

sprinkled with oregano and drizzled with extra virgin olive oil for
dinner, so I can't help with that search right now. :-(

How is "extra virgin" olive oil different from plain ol' ordinary
everyday olive oil, other than the price?

"Virgin" means that it's olive oil (no chemicals added).
"Extra-virgin" means it's from the "first pressing" of the olives and
is supposed to be better. Neither of these terms have any legal meaning
and the meaning words, if not the oil, are often adulterated.

It means that it's green and putrid-tasting.  You have to add balsamic
vinegar to cut the taste, and then put it over bad-tasting 'baby greens'
to make a modern salad.  Ain't progress wonderful. :(
Phil "plain lettuce forever" Hobbs

Oh, Honeymoon salad?

"Lettuce alone, undressed."

I like my salad like I like my women - not dressed. ;-)
Click to expand...

Cheers!
Rich
 
On 2011-02-17, George Herold <gherold@teachspin.com> wrote:
On Feb 17, 7:38 am, John Fields <jfie...@austininstruments.com> wrote:
On Wed, 16 Feb 2011 12:23:18 -0800 (PST), George Herold
Click to expand...

How 'bout something else... surely there's lots of ways to sense the
RPM of a motor.  Can you pick off a signal that does the spark
timing?  Maybe a coil wrapped about the spark plug wire?

As a capacitive pick-off?

No, I was thinking about sensing the current in the coil....
Click to expand...
I think John was picturing your descritionj being a coil wound round the plug
lead. I can see a way to wrap a coil round a plug lead and achieve
magnetic coupling, it'd be wrapped in such a way as to form a toroid
shape.

better to work on the primary side as Whit3rd suggested.
Click to expand...
Yes, this is how most automotive tachometers work.

anoter way to do it would be to sense the leaking magneic field of the
spark coil.

or to put a coil in a magnetic field near the ring gear on the
flywheel (or tap the one that's already present in many vehicles)



--
⚂⚃ 100% natural
 
On Thu, 17 Feb 2011 13:58:18 -0600, John Fields
<jfields@austininstruments.com> wrote:

You can't sense the current in a conductor by wrapping a coil of wire
around it.
Click to expand...
Several turns of wire around a spark plug wire will work
just fine for tachometer purposes. With a simple limiter
you can read the RPM directly using a sound card. See
"Engine RPM Measurement" at
<http://www.daqarta.com/dw_0a0r.htm>.

Best regards,


Bob Masta

DAQARTA v6.00
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!
 
On Feb 19, 5:17 am, N0S...@daqarta.com (Bob Masta) wrote:
On Thu, 17 Feb 2011 13:58:18 -0600, John Fields

jfie...@austininstruments.com> wrote:
You can't sense the current in a conductor by wrapping a coil of wire
around it.

Several turns of wire around a spark plug wire will work
just fine for tachometer purposes.
Click to expand...
Both these statements are right. A 'coil of wire around it' doesn't
achieve current sensing unless your winding is not a simple
wraparound, because it's parallel windings that have flux
coupling. The wire-around sensor is a capacitive (voltage
spike) sense transducer, not a current transducer.
 
On Sat, 19 Feb 2011 13:17:39 GMT, N0Spam@daqarta.com (Bob Masta)
wrote:

On Thu, 17 Feb 2011 13:58:18 -0600, John Fields
jfields@austininstruments.com> wrote:

You can't sense the current in a conductor by wrapping a coil of wire
around it.


Several turns of wire around a spark plug wire will work
just fine for tachometer purposes.
Click to expand...
---
That wasn't the point, though.

---
JF
 
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