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dr DAQ light sensor

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dr DAQ light sensor

Postby Hugo Rune » Sun May 11, 2008 11:14 pm

I have been running a few simple tests after reading an article about lighting, which basically said that Metal Haliide bulbs give off more plant usable light than High Pressure Sodiums, and that horticulturalists are wasting money and power using hps in the flowering/fruiting stage of growth.

I decided to put this to the test, I have the two types of bulb at 600W, which is a bit bright for the light sensor on the DrDAQ unit.

So I took a couple of lenses off some sunglasses, wrapped them in 3 layers of white gaffer tape, and taped the lot over the light sensitive device on the DAQ. This proved to be an adequate filter, and brought the reading on the meter to around 60.

This is enough for my purpose, I don't need to know precise light levels, just relative levels.

first I measured the 600W hps from startup for 20 minutes and it settled down to a final reading of 60.9

Then I did the same for the 600W mh, expecting the reading to be a bit higher, as according to the article I read, but was surprised to find that it only gave me a final settled reading 48.8

I can accept that there maybe some slight difference in my test setups that could introduce error, for example when changing the bulb the reflector might be in a slightly different position, but I tried hard to replicate the same conditions, and am confident that the difference cannot be from setup.

So now I need to eliminate the next problem, the light sensor on the DrDAQ unit may respond differently to the two different lights, HPS is more at the red end of the spectrum, and MH has more blue.

So I need to know precisely what the component is on the DAQ, so I can find its tech specs.

Can you help?

Hugo
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Postby picojohn » Mon May 12, 2008 2:05 pm

Hello Hugo,

We do not normally provide details of our product designs but, as this is an easily identifiable component, I can tell you that the sensor is from Radio Spares and their part number is 596-141.

I trust that helps.

Regards
John
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Postby Hugo Rune » Mon May 12, 2008 2:33 pm

Easily identifiable if you have good eyes, mine unfortunately let me down, comes to many with age :?

Thanks for that it will help a lot, I think...

I also need to source proper photographic filters, the sunglass lenses are a more likely source of the difference.

Again thanks.
Hugo
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