still can get your point.
the “convex thing” above the yellow part will not influence the spectrum? the light is reflected and refracted maybe multiple times. in a word, I am really novice in this field.
For correct LED measurements, the flashlight must be disassembled - the secondary optics (lens, collimator, reflector) must be removed. There are very different designs of flashlights. Different secondary optics can change the light parameters to a different extent.
Opple EU won’t sell this device until it’s working. I was in contact with the NL headquarter last year and they were pretty clear about that.
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so the inaccuracy of LM4’s measurement of flashlights is acceptable? because seems nobody removes the secondary optics(lens, collimator, reflector) here.
so only and if LM4’s performance is at least as good as LM3’s can we sell it in EU market?
It is important that the measurement of the light shining on the sensor is more or less correct.
For me discussion about removed secondary optics or something like this is theoretical, since it is important that the device has to measure the light which shines on the sensor. A device for mass-consumer market, which only gives more or less exact measurements if very specific requirements are fulfilled is not well designed, imo.
For calibration and development of software etc it is necessary to measure emitters with known spectral data (without any secondary optic, in integrating sphere, on proper heatsink, also important that the measurements are reproducible ) like in my LED tests.
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Depends on the task. Whether we are measuring an LED or a flashlight.
Correctness of measurements of the LED itself with secondary optics depends on the properties of the secondary optics.
so in the end, in your opinion how can I improve LM4? I think first the resolution limitation is real and we must accept this reality, not compare LM4 with professional devices like CL-200A or CL-500A. then is how to achieve as7341’s full potential in spectral measurement. you know I am kind of feeling astonished by LM3, because seemingly LM3 is well received/recognized by you guys.
I saw posts before in this forum, people measure flashlights instead of LED. the secondary optics matter.
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Anyone can verify the differences of measurements with and without secondary optics. Each flashlight will have its own differences.
I will not buy LM4. All claims to LM3 I wrote above.
That’s how I would understand it.
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I think the only way is to fully open the device specs (BLE protocol etc) to give the community the possibility for developing own software/calibration methods.
Then it is important to have several emitters (white, monochromatic, phosphor converted) with known spectra on hand, to get a high bandwidth of it.
According to these data, an algorithm has to be developed to get more or less precise data. In my opinion, this is absolutely essential.
But I don’t know if there is any interest of doing so by Opple.
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just consulted with my manager, LM will not open source, OPPLE signed NDA protocol with bluetooth chip supplier. and it’s company level decision, we employees can’t make a decision. sorry.
Even if the software itself can not be open sourced, maybe a documented API on how to communicate with the device so people can write their own software around it?
That’s unfortunate… 
For this circumstances I don’t have no real hope that the software would be as good in terms of measurement accuracy… so all depends on knowledge and goodwill of management to get a much better result for LM4.
Maybe we are able to develop some device like the LM4? (just an idea, the sensor is commercially available at least) - or idea with API could be a solution, but if such an API is usable to create own software, I don’t know.
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OPPLE signed NDA protocol with the BLE chip provider, if we open source it, the provider would sue us. so, sorry for this. I personally fully support opening source LM, so we can together make it better.
why not give your ideas here? after all, OPPLE is a commercial company, hope you understand.
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I still would like to know what max flicker frequency Hz can OPPLE v3 measure compared to v4 ?
I don’t understand this. Customers of your lights already know the specifications of your lights. I think the LM4 would be useful to measure old and unknown light installation to find the matching Opple product.
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I don’t understand their idea too.
the minimum sampling time span for flicker is 11µs, according to Nyquist sampling theory, the maximal frequency is around 1000000 / 22, about 45K Hz.