rickman  wrote:
> As is common on usenet, a post is made asking for info and many posts are
> made assuming facts not in evidence.
>
> I guess in all fairness I did ask for people's "thoughts".  lol :)

Since we're assuming, I'm going to assume you're asking about this wearing
your comp.arch.embedded hat, or equivalent application thereto.

> I was asking about the hassles of trying to use a phone without the tyranny
> of the phone company, whether it was hard to pick the OS I use and write
> control code.  I found some info on using the phone either with a bluetooth
> serial port connection or using the USB port for a serial connection and
> there even seems to be some info on using the USB port directly as an async
> serial port.

Generally the way this goes is that you have to treat the phone or tablet as
an appliance.  You get whatever you're given, you don't change the OS
(either you can't or it's too much work).  You install an app on it that
uses the standard Android/iOS APIs for talking to hardware - Bluetooth,
wifi, USB.

A year or two down the track you replace the device with a newer model.  You
might have to tweak the app for the newer OS (new graphics, recompile or
whatever).  Since you're using a standard hardware interface that bit
doesn't change (modulo micro USB to USB-C or whatever).

The solution to 'make it secure' is to buy a newer device every two years,
and hope it hasn't been infected in the meantime.  Android security is a
car-crash, and to a first approximation doesn't exist.  For iOS you might
get 4 years.

A Raspberry Pi is the antithesis of this kind of appliance-like model.

If you really want to treat the phone/tablet like a Pi, find a device that
supports Lineage OS, which is a build-from-source version of Android.  They
will hopefully keep it updated, though it's all dependent on volunteer
labour keeping particular models of devices supported.  It's more likely to
get security updates but quite possibly won't get newer OS updates when
either the volunteer devs aren't interested or something in the newer OS is
incompatible with your phone (eg the binary blobs provided by the vendor).

Theo

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