Wind Sensor Colder Air

Questions about Modern Device and JeeLabs Sensors
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John559
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Joined: Tue Oct 28, 2014 8:29 pm

Wind Sensor Colder Air

Post by John559 » Wed Oct 29, 2014 10:04 am

Hi. I recently purchased the Rev C Wind Sensor model listed on the website. I'm planning on using it for a small school project that doesn't require a great degree of accuracy. After I setup the circuit between the Arduino and the sensor and began running the relevant GITHUB sketch, I tried to test it out with different wind speeds. However, the sensor didn't seem to respond to cold air nearly as much as it did warmer air. Specifically, breathing on it produces noticeable results in wind speed while blowing on it produces next to no fluctuations in the wind speed. So, is there any way to calibrate the sensor to be more sensitive to colder air rather than warmer air? My only goal for the sensor is to detect when wind flow is occurring, rather than obtaining an actual value. I have my GND pin running to GND, +V running to 5V, RV running to A1, and TMP running to A2. At the moment, I'm not utilizing the OUT pin. I think this is in line with the sketch. I'd appreciate any and all help. By the way, is there a position on the sensor the wind should be hitting it for the best results?

Thanks.

paul
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Joined: Mon May 12, 2008 4:19 pm

Re: Wind Sensor Colder Air

Post by paul » Fri Nov 07, 2014 8:18 am

John559,

Colder air is a complicated question. The temperature of the sensor is constant in the circuit. So colder air registers higher raw voltages (at still air), because it takes more energy to bring the sensor to temperature. When the sensor sees wind, there is less overhead before the output hits max at about 4.4 volts.

You can power the sensor from a higher voltage - up to 10 volts, and that will lend lots of overhead in colder temps. Unfortunately my sketch has been designed for 5 volt supply, so the ambient temperature compensation is going to be off. You could try scaling (reducing) the temp output (it's just a voltage divider measuring temp) proportional to the input voltage, feed it into the sketch and see how you make out.

Hope that helps,

Paul

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