pcb-mount air flow sensor

This has been discussed here before. I still don't understand why infrared is mandatory. Over here all the electric garage doors have a pressure switch and a rubber hose running along the edge of the door.

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Reply to
Nico Coesel
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^^^^ ^^^^ :)

Tim

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Reply to
Tim Williams

Michael A. Terrell schrieb:

Hello,

I already knew that before.

Bye

Reply to
Uwe Hercksen

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They're mainly supposed to help reduce deaths of children. Here's the ruling:

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and an update

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Worth it?

Best regards, Spehro Pefhany

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Reply to
Spehro Pefhany

Columbia College requires no thesis for graduation -- did Obama write one for the fun of it?

Reply to
spamtrap1888

For that alone it's worth it, but it should do more than just avoid crushing kids. A contact sensor with redundant switches should be at least as reliable. It could reverse the door except when it's within an inch of the bottom, at which point it could stop without reversing.

Fortunatly the ruling allows that as an option, instead of the usual micromanagement.

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Reply to
Tom Del Rosso

Jeff Liebermann wrote in news: snipped-for-privacy@4ax.com:

Yes,I got that. I just wanted to bloviate about taking my old sensor apart! It's a neat piece of technology.When I was at TEK,I sawed apart one of the mixed analog/digital hybrids from the 2465 scopes,the ones that look like little cylinder heads and bolt down to the motherboard.

I've used that CRC sensor cleaner. but my MAF failure was a total one. I was able to find a replacement sensor online for $78,while most places would only sell the sensor AND housing for $300-400...with exchange. (they want the old housing back so they can scam another person...) Naturally,they used 5-lobed Tor-X type security screws to mount the sensor in the housing,but I worked around that.

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Reply to
Jim Yanik

AIUI, It is Harvard who locked up Obama's law school thesis... probably because it advocates communism.

And a lot of schools have stopped having theses in "recent" years. For instance MIT no longer requires an undergraduate thesis. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
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Reply to
Jim Thompson

The bins of visible LEDs are usually ranges of (milli) candelas, which is the LED power output weighted by the spectral sensitivity function of the human eye.

Reply to
Spehro Pefhany

about maybe using two LM71 temperature sensors, one mounted on a copper po= ur with a resistor heater. We don't need a lot of accuracy... this would be= mostly a fan fail sensor. -- John Larkin Highland Technology, Inc jlarkin = at highlandtechnology dot com

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Precision e= lectronic instrumentation Picosecond-resolution Digital Delay and Pulse gen= erators Custom laser drivers and controllers Photonics and fiberoptic TTL d= ata links VME thermocouple, LVDT, synchro acquisition and simulation

If you don't require a lot of accuracy and only need the fan fail signal (O= n/OFF signal), the Flexpoint Bend resistant Sensor can meet your requiremen= t. The sensor is cheap, if you have any interested in the sensor, you can c= heck the link=20

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also, you will find a flow meter vedio for a similar application.

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Electrical Engineer=20 Fengfeng

Reply to
xiaoshanj

71

er.

sor.

?

The output is linearized with Vaf by maintaining the Vbe in ratio. This one= has been around a while:

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but it's probabl= y more parts intensive than you hoped for.

Reply to
bloggs.fredbloggs.fred

Electric cars and blackouts can be mutually exclusive with good engineering. Engineering in India is barely better than Arizona.

Reply to
miso

Depends on what you pay for, the military has required peak wavelength binning as well. They paid for it too.

?-)

Reply to
josephkk

resistor

fan

pulse

That is a useful method as well. My garage door opener has a force = sensor that causes the door to reverse and open again if too much force is detected. I can reverse it with my arm a foot (300 mm) from my body.

?-)

Reply to
josephkk

What about a single strain gauge element stuck up into the air flow, mounted from the pcb on stiff wires. Have three more resistors on the board to complete a Wheatstone bridge. Strain gauge elements are usually a resistive material on a plastic (kapton) backing. Air flow would cause the element to bend in proportion to air flow, changing voltage across bridge..

Reply to
lektric.dan

More likely you are full of shit that the thesis advocates communism. For one thing, he didn't study economics, so communism is extremely unlikely. Further, communism was called command economics and/or planned economics in that era.

I'd suggest you stick to something you know like electronics, but we are all doubtful about that too.

Reply to
miso

=20

=20

I don't think there is a thesis for Harvard Law. The controversial thesis w= as a 44-page document entitled Aristocracy Reborn, which was required for a= senior seminar in his political science major at Columbia University. Ten = pages have been released, somewhere. It's nothing exciting, just some brain= dead undergrad ranting about plutocracy and knocking the Constitution for = failing to address distribution of wealth. It is at least somewhat relevant= , in contradistinction to that wimpy English major at Brigham Young Univers= ity.

Reply to
bloggs.fredbloggs.fred

The customer had ordered some equipment, when it first hit production, then additional units about five years later. Needless to say, the newer LEDs were brighter, and it bothered them so they shipped the equipment back. The lowest available bin was as close as we could get to an exact match, unless they wanted to spend about $500 a unit to have the older models modified.

Reply to
Michael A. Terrell

Yawn. We are in dire need of new power plants, and the extra load from electric cars can cause problems. The dumb ass liberals want to shut down coal & nuclear, then advocate those crappy oversized electric skateboards.

Reply to
Michael A. Terrell

Pajamas Media. Yep, no bias there. ;-)

Reply to
miso

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