[Tinyos-help] calibration experiences with tmote temp and photo sensors

[Joe Polastre]

> The temperature calibration looks straight forward enough, but I had
> some questions about the calibration of the light sensor. Is there any
> device you recommend for taking the reference reading of the lux level?

A pyrometer is typically used for light calibration.

> How many calibration points do you typically do yourself?

At least 2, depending on the response curve of the sensor.

> Also, sorry if I missed it but I didn't see any conversion from ADC
> value to SI units for the S9067 light sensor. I looked on the tinyOS
> message list, the net, the Hanamatsu company website and the moteiv
> support pages, and could see it. Do you have for instance a pdf with
> this information.

See pages 27-28 of the Tmote Invent user's guide.  It tells you how to
calculate the photocurrent, I, of the sensor based on your gain
settings.  The S9067 datasheet at www.hamamatsu.com has a graph of Lux
vs Photocurrent.

http://sales.hamamatsu.com/assets/pdf/parts_S/S9066-01_S9067-01.pdf

-Joe