Subject:
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Re: Cheap air flow sensor
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Tue, 16 Jun 1998 14:23:51 GMT
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Original-From:
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Sathe Dilip <sathe_dilip@bah.#NoSpam#com>
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Viewed:
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1193 times
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Elektor had published a similar circuit for detecting air leaks. The
heated transistor and another transistor acting as temp. sensor were
glued together using heatsink compound. You had then to
nullify/calibrate a meter at ambient temp. when the transistor pair was
held near a air leak, the temp. difference caused a meter deflection
(basically the current required to maintain the transistor temp. was
monitored). The circuit was not meant for absolute air flow measurement
but could probably be modified.
I have this schematic somewhere at home. May take a couple of days to
draw it in ASCII (I am not good at it :-). Let me know if you are
interested.
Newark electronics used to carry a capacitive humidity sensor for about
$ 12. The same device is manufactured by 2-3 companies. I know Philips
and Volvo as two of these.
Dilip
Jonathan Swaby wrote:
>
> Does anyone know of a cheap way to construct an air flow sensor? I was
> looking for an article in EDN on using a self-heated transistor to measure
> airflow, but Ican't find it.
>
> I was also wanting to know if there is a way to create a humidity sensor,
> or does anyone know of a low cost part?
>
> I am wanting to connect these to a miniboard.
>
> Thanks
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Message has 2 Replies:
 | | Re: Cheap air flow sensor
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| Finally I managed to put the schematic of Wind-O-meter described in the Elektor publication in ASCII. Pl. set your reader font to something like courier to view it properly. I have taken some liberty with the opamp symbol to accomodate some (...) (26 years ago, 22-Jun-98, to lugnet.robotics.handyboard)
| | | Re: Cheap air flow sensor
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| Electronic Design "Ideas for Design" section had a interesting circuit for a Low-Power Thermal Airspeed Sensor in the May 25, 1998 issue. It's more complicated than the Elektor design but the ariticle helps explain thermal anemometry with the King's (...) (26 years ago, 22-Jun-98, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Cheap air flow sensor
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| Does anyone know of a cheap way to construct an air flow sensor? I was looking for an article in EDN on using a self-heated transistor to measure airflow, but Ican't find it. I was also wanting to know if there is a way to create a humidity sensor, (...) (26 years ago, 15-Jun-98, to lugnet.robotics.handyboard)
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