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Topic: Air flow sensor Honeywell AWM92200V - ancillary circuits (Read 1 time) previous topic - next topic

Sean Wagner

Hi all, I have above air flow sensor that I'd very much like to use with the Arduino, but after reading the datasheets and searching the forum, I do need help hooking it up. Programming is not the problem, but my lack of electronics know-how. It's sitting here waiting to have a blast (of air)!

While I'm at it, maybe someone knows a good source for the appropriate 5 micron filter.

My main reference doc is attached below. It should contain all relevant info.

Voltage vs. Output on page 3 - min / max are -80 / 80 mV (Don't need the neg. value.)
- What would a smart amplification circuit look like?

Wiring diagrams on page 4
- I guess the unspecified resistors are internal?
- The little house-like symbols must represent the sensor pins?
- And I don't understand which pin provides the output Voltage! (Argh.)

Product page:
http://sensing.honeywell.com/index.php?ci_id=3108&la_id=1&pr_id=25901

I'd very much appreciate your help!






MarkT

Firstly its a bridge circuit (Wheatstone Bridge) and so the usual amplifier circuit you would employ is an "instrumentation amplifier" - these days very good versions are available as a single package, check out the INA range from Texas Instruments for instance.

Secondly the device has a heater that needs driving (there's an example circuit for that in the documentation "control circuit diagrams").

Yes you are right about the house-shaped symbols being pin numbers and the unlabelled resistors in the lower-half of the bridge being on-chip.

I'm surprised Honeywell don't seem to have a proper datasheet for this - it would be much easier to work out if it can be driven at 5V if they weren't so coy about the information!
[ I won't respond to messages, use the forum please ]

Sean Wagner

Thank you Mark for the great leads! Now I know what to read up on.

The attached reference doc (page 1) does mention supply voltage from 8.0 - 15.0 Vdc "while consuming 50mW of power".

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