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Author Topic: Calibrating the Hobby Board 1-wire UV Sensor  (Read 1054 times)

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Online blainec

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Calibrating the Hobby Board 1-wire UV Sensor
« on: March 28, 2012, 11:26:14 PM »
I have noticed that my new sensor has been reading a bit high.  For example, today it reported a high of 9.2 however all the big weather sites are reporting a high of only 4.
I don't have any info on calibrating it or what values I need to enter. Can anyone assist me?

Thanks

Offline KeithBC

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Re: Calibrating the Hobby Board 1-wire UV Sensor
« Reply #1 on: March 29, 2012, 01:04:04 AM »
I don't know how you would go about recalibrating it.  I do know that it is susceptible to some errors. 

The temperature compensation is not good.  At cold temperatures, it overreads even with the built-in temperature compensation turned on.  About +0.5 UVI at 5degreesC at midnight (actual UVI should be zero then).  The overreading seems to be getting worse over time. 

It also gets reflections from the window at certain sun angles.  I'll get a spike in mid-morning and mid-afternoon just from the internal reflections.  There are several reflections.  I have not identified them all, but some are off the sides of the window.

Online blainec

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Re: Calibrating the Hobby Board 1-wire UV Sensor
« Reply #2 on: March 29, 2012, 01:44:48 AM »
I will have to track it to see if I can identify any reflections from windows, however, it is a fair distance from any windows  (about 40 feet)

Offline KeithBC

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Re: Calibrating the Hobby Board 1-wire UV Sensor
« Reply #3 on: March 30, 2012, 03:26:34 PM »
Sorry I wasn't clear.  The window I was referring to was the little plastic window on the sensor's mounting box.  It is 1/8" thick, making each edge a little 1/8" high mirror that reflects down onto the sensor.

 

cumulus