Pinephone LED Fresnel lens - Commentary

[vortex]

Pinephone's case covers the LED with a Fresnel lens probably to diffuse the light.

The problem is that the lens analyses the spectrum of the white light and produces circular rings of different wavelengths(colours), so we start from a warm yellowish colour in the middle and we reach blue on the outter periphery.

Just tested the light and it is definitely rather yellow in the center and a bluish white around the edge.

I don't think it is chromatic aberration in the lens. I did some looking and I cannot find achromatic fresnel lenses, even big lenses from the folks who make lenses for instruments and scientists (Edmund, Thorlabs, Newport, etc.). There are more than a few papers on the topic though. Of course, it could be done and perhaps there are ones available that other phone manufacturers use (e.g. go to a custom optics manufacturer and have thousands or millions built at a time), but then most likely there would be at least someone selling them in smaller batches. So I think most likely no one is using achromatic fresnel lenses. Also, this is pretty strong for chromatic aberration. So I don't think it is the lens.

I think it is more likely that it is a problem with the LED's phosphors. Most likely there is too much in the middle converting blue to yellow. Means just the LED has to be switched for another one, for better (better selection of LEDs than lenses) or worse (soldering if doing oneself, possibly need to recertify if done as a revision in manufacturing).

My general observation is that Pinephone seems to be purposefully designed to be of inferior performance comparing with phones of a similar class, everything somehow "isn't working so well" for no specific reason though we have already been many years in the age of smartphones and we also have many years of experience with Ubuntu Touch.

I doubt that bad performance was the intent. However, it is definitely true that the chosen hardware has poor performance in many ways (including power). A lot of choices were made to get certain things at the price of performance.

The CPU and its internal GPU are quite puny for example, but were chosen because the pinefolks have a lot of experience with the processor and its relatives (helps a lot in designing the PCB and getting things like RAM to actually interface with it)  and it can be run with few blobs (which also helps with supporting the processor for a long time).

Separate discrete components as opposed to an all in one SoC means more power consumption and also worse performance (a SoC where the wifi and modem can just read and write to RAM at will will obviously be faster than ones that must go through the motions of a USB connection), but help with security since there is a verifiable barrier (a USB modem definitely can't access the RAM at will unless there is a bug in the USB controller in the CPU) and it is possible to for sure be able to power down the devices and know they can't possibly turn back on (hardware kill switches).

This combined with the small batch size of the PinePhone mean that the hardware limits to its performance are quite abysmal compared to other smartphones for the same price. This is in exchange for more configurability and control, being able to run something closer to a mainline kernel (and quite likely an outright mainline kernel eventually), better hardware security properties, higher chance for a long time of software support, actually getting the PinePhone manufactured in a reasonable amount of time after the project started (experience from the other pine products carried over due to similarities), etc. The small batch size definitely doesn't help, but one has to start somewhere for a project like this. Have to actually have some phone hardware in people's hands to get the development ball really rolling, and at this stage not many people are interested in a phone like this and at this stage in development and thus the batches are small.

So the question is, is the price in performance worth what is gotten? For me, I think yes. For others, the answer is no.

The software end is interesting. The main problem is that while software on the PinePhone stands on the shoulders of decades of software development for GNU/Linux on other computers, that same software was not designed or tested with the form factor PinePhone in mind and a lot but not all not designed or optimized for the performance limitations (I say not all because people have designed and optimized software for the Raspberry Pi which also has puny hardware). Screen size, on screen keyboard use, portrait mode for a screen with this aspect ratio, performance issues (a program that performs just barely well enough on a typical desktop is going to really struggle on the PinePhone). Also, the PinePhone has a lot of things not exactly on most desktops and laptops (e.g. camera flash) or are used differently (modem used to make calls, not just to get internet). So it is taking a long time to get software up to par for it since existing software has to either be adapted (time consuming and sometimes run into limits due to design issues) or built from the ground up.

Android software would be hard to port because the android ecosystem works very very differently.

As for software from UB, doesn't UB have an android-like API? If so, it would be quite hard to port software meant for that over. Not impossible, but a lot of work. But such ports would definitely be well suited since it was designed for smart phones.

The software definitely has a long long long ways to go.

The same observations apply to the audio quality though I have not still researched whether I can somehow optimise it except for putting the Pinephone in a box to gain some bass.

and yes, I would replace a chip to get some things done like energy efficiency or audio quality, even the cheapest garbage has better audio quality than Pinephone, why?

I'm still early in testing audio output of the phone. Haven't tested the bass range. What testing I have done so far indicates that the PinePhone's best audio quality is obtained on low volume. Speaker is definitely powerful, but doesn't work as well across the whole frequency spectrum at high volumes.

I've mostly been having problems with sound recording. Currently working on narrowing down the cause and hoping there is a software solution.

As for energy efficiency, it was the price paid. That said, there is room to improve the power consumption some from the software side. The work on putting new firmware on the modem has already been able to reduce power consumption some and some kernel improvements are being done to reduce power consumption as well (see https://xnux.eu/log/#033). But there are definitely limits to what can be done.



As for the various issues that the phone has:

There are hardware choices that are part of the price paid to gain desired features like rather open hardware. Not much that can be done about it at the present time other than spend effort reverse engineering other chips to increase the number of choices for future phones. In the future, there may be more choices available. For now, for the particular goals of the project, there are sacrifices one has to make.

There are hardware choices that do not impact the goals like open hardware where there is a lot more leeway in the choices and things can potentially be optimized. The LED for the flash is a good example of a hardware issue that can be solved and improved upon without compromising the main goals of the phone. [EDIT - added something missing] The LED flash, speakers, and similar things like that are definitely fair game for criticism and things to possibly improve in future pinephones when there are problems.

And then there are the software issues. Those require time and effort to mitigate by developers, tinkerers, testing by users, etc. (note there is a lot of overlap between these). There is A LOT of work to do.

[EDIT] - added something missing two paragraphs up