So with further testing it seems to help a bit , but it’s still not reliable in the least- with far more errors than connections.
Hello Gents!
I just received my LM4 and it turns out it likely doesn’t work with my iphone at all, and even if it would, the app would not do what wish it did. Bummer, if only I spent more research, but then I found this thread and I am actually intrigued now!
I am a photography as my main source of income and I’ve always looked for small devices I could use to quickly check the color components of my lights, so I could for one adjust the white balance of my LED Lamps and secondly to get an impression of the light quality I am facing and make better decisions that would make editing simpler, quicker and the results look better.
But I am also a maker with a solid backround in hardware and electronics, reasonable coding skills and sometimes too much time to spend on things that my focus locks on to 
Seeing this thread with so much information about this device sounds like Gold, so nice to see steve in here, and many people with a genuine technical interest about the device! I actually wanted to return it right away, but I think there is hope for my use case.
Really all I need is proper CCT/Tint values, and if I get a color spectrum overview and brightness information, that’s a great benefit. However, what I really need is a speedy app that I can use within a few seconds. BLE should be able to do that and I also have a paid apple developer account so I can actually do bluetooth code for ios, I’ve tinkered with that in the past and I think I could get some things done once I find some time.
However, what I have not found is documentation about the Device itself. Are there any information about BLE GATTs and the protocol used by the device? Same for serial port. I’ve only found compiled binaries for windows and android, which are of little help if I wanted to do an ios version.
Coudl anyone of you give me some pointers on where I’d need to look at? Also has anybody torn down the hardware and taken some images? What kind of MCU does it use?
Not possible with this device. It just estimates the values from a few samples.
Also not possible. The sensor of the LM4 has only eight color channels:
This is not enough to reconstruct a spectrum properly.
No.
Hmm, well I only need ballpark values, no scientific readings for CCT, anything else would be a bonus.
how are people writing apps if there is no ble documentation though?
AFAIK only Steve wrote apps and he was working for Opple (but not anymore).
So @stevechang, would you be able to share some protocol documentation, so I could make my own ios implementation?
Steve said before that all info from the sensor manufacturer was under NDA so nothing can be shared.
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Check out the Discord mentioned above, or check some of the earlier posts.
well, the sensor can be bought from Mouser for 7€ including datasheet. I’m not sure what NDA would still apply, I only want to interface with the device via bluetooth.
I have read though most of the forum already and didn’t find any specific information, it’s a long thread, so it’s not unlikely I have missed it.
Is there anything useful I could find on the discord? Because, as of how the replies went here I figure it’s not worth spending any more time on this device and it would be much smarter to just return the device …
The problem is finding something similar under 50$/€
I thinks this is the only device with this price point and capabilities.
Greetings.
The hardware datasheet, yes. IIRC the proprietary confidential part was the spectral reconstruction algorithm.
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Opple Smart does not work for me, I always get a camera screen that asks me to “scan the qr code created by the project owner”. and that’s all I can do with the app. Adding to the fact that apparently if requires a login to work properly. If you’d choose to create an account, it would only allow a password max 15 (!) characters with no special characters 
Yes I get scared away from apps very easily.
I also don’t use windows, so that’s out of the scope for me unfortunately
I also agree with Boreack, it’s the reason I bought the device in the first place. But if I need to spend time to reverse engineer the protocol with very little information present, and the sensor is available for 7€ bare metal, I can choose my own MCU, design my own PCB, add a screen and some battery management, and with the magic of chinese pcb manufacturers I have my own design in the same amount of time for insignificantly more than 50€, only some more time spent. But I know exactly what I have at hand.
I’m really just balancing out what kind of gain I get for the time spent, and it really seems returning the unit is the better choice in my case.
If you finally make one, with the cheap sensor and some other parts, share It here so we can make one 
Greetings.
indeed signed NDA, although I left, Opple could sue me if I’d share.
you must firstly make sure all AS7341 readings are aligned between different chips, so there is a fixture that is used to calibrate AS7341 readings. then broadcast AS7341 readings through Bluetooth. through the type-c like interface you can also retrieve AS7341 readings, it’s actually serial communication protocol, you send specific command to firmware, it’d give you AS7341 readings.
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I have kind of a dumb question .
Why doesn’t OPPLE just keep making and selling an upgraded version of the 3 ?
The 3 sold well and they still sell other older models don’t they ?
Change something that is meaningless like the speed at which the light turns off or the color of the buttons , add a red lanyard and call it the super pro plus .
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Because it was more of a device for marketing to let customers see how great their lights perform. And they might have realized it wasn’t worth the effort.
The 3 was (quite a bit) inferior to the 4. Worse sensor. The 4 only suffered from a terrible software. Steve fixed that, but nobody at Opple was interested in his improved algorithm that made the 4 more accurate and reproducible than the 3.
The LM4 was essentially just trained for the few led types Opple used, to measure those accurately, so their customers can see how well their new lights perform. They never cared about whether it can be used as a universal measurement device.
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So which one is more accurate? LM3 with web app or LM4 with desktop app. I get different CCT, different duv, different Ra measurements with same light source.
I have two LM3’s and two LM4’s. One of the LM3 comes close to pro reviewers’ numbers (eg Nichia 219b 4500k Duv around -0.0080 to -0.0100 depending on light and optic, etc.), the other LM3 slightly off. The 2 LM4’s are much further off using all available apps. I don’t trust my LM4’s (Duv, Ra, R9) and don’t use them anymore.
Of course this is with my 2 specific LM4’s. Can’t vouch for others/YMMV. IMHO if you see any LM3 for sale, buy it immediately. Unless of course there’s price gouging.
I absolutely love the web app for LM3 HERE and recommend it extremely highly. The continuous Duv reading is life-changing especially with LED that changes constantly with temp and outputs like 519a.
Thank you for information. I also felt, that LM3 with web app is more accurate, at least CCT values and duv