Sensor Lux 'Max Out'

[Travelfool]

Hello,

I am trying to build a Arduino based system to measure the climatic conditions for a project in N.E. Brazil, fairly near the equator. The aim is to measure the outdoor conditions and then replicate them using lights, sprinklers and other necessary gadgets when the weather is not so good. I am confident already on measuring the humidity, temperature and ground moisture levels but I am struggling on getting readings for the light values.

There is defiantly a correlation between the light strength, probably a mixture of visible, UV and IR light, and the success of my project.

I am currently playing around with the two light sensors, the TSL2561 and the GA1A12S202. Unfortunately both of them get 'maxed' out easily, at 40,000 Lux and 55,000 Lux respectively. When testing them here in the UK (where I am from) both of them are being maxed out in direct sunlight, and I would not really say that when I was testing them today it was that sunny.

As I understand it, full sunlight can reach 120,000 lux and my project requires sunny days with minimum conditions of 40,000+ lux (this was only made clear to me after my purchase of the TSL2561 and the GA1A12S202 ;p ). I am assuming, with some confidence, that the sunshine levels near the equator will be in the very upper range of Lux pretty early on in the day and probably always reach near maximum Lux range during the middle of the day.

I have been Looking at the TSL2591 as an alternative (up to 88,000 Lux) that also has the added benefit of measuring IR, which I also want. However I am also worried that this will also easily get maxed out. Do you know of any way to extend the readings of the light sensors, such as using using resistors, while maintaining actuate readings. Alternatively do you produce or know of any other products that would be able to measure in this range?

Also do you have any recommendations for the UV sensors, the SI1145 and the GUVA-S12SD? I know the former does 'other' light readings, but I think the TSL2591 is a better option for those readings.

I am interested in data that I can use to refine and hopefully replicate, as mentioned above. I am fairly comfortable at using the sensors and the Arduino, but that's about as far as I would say my abilities stretch.

If anybody is interested I am trying to help a recycling project breed insects to eat waste food. I am sure not many would have expected that from the above text =)

Any and all help welcome. Thank you

[adafruit_support_rick]

Well, you could use a neutral density filter, I suppose.

You could also check out the Si1145. It's designed for direct sunlight, and goes to 128kLux.
https://www.adafruit.com/product/1777

[Travelfool]

Hello Rick,

Thank you for your response. My coding is very weak at best and I am really grateful for the breakout boards, tutorials and associated coding your guys & gals produce. I already have my hands on a Si1145. I apologise for the naive question, but do you have any arduino code that I can use to get a Lux measurement as well as the 'visual, IR and UV' readouts form the Si1145 breakout board?

I look forward to your response. Thank you

[adafruit_support_rick]

We do not. However, see this thread for a discussion of lux with this sensor
http://forums.adafruit.com/viewtopic.ph ... ux#p302193