 | | 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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| | Re: Cheap air flow sensor
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We have used model boat propellers on a ballbearing and on a brass bushing. Keep the bearing or bushing well lubricated for good sensitivity at low air volume (ie: low speed of the propeller). We used the propeller mounted in 1.5 inch and 2 inch PVC (...) (26 years ago, 15-Jun-98, to lugnet.robotics.handyboard)
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| | Re: Cheap air flow sensor
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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 (...) (26 years ago, 16-Jun-98, to lugnet.robotics.handyboard)
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| | 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)
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| | Re: Cheap air flow sensor
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(...) (circuit and description deleted) Neat idea! It reminds me of a simple variometer (rate of climb/sink) circuit in an old RC glider magazine. It used two small naked bead or glass encapsulated thermistors in a bridge circuit and the thermistors (...) (26 years ago, 22-Jun-98, to lugnet.robotics.handyboard)
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| | 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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