[time-nuts] RPi/ beagle bone-like computer without video

[Scott Stobbe]

As much as it pains me to recommend them some of the iot modules sound like
a good fit, like the Intel atom one.

On Fri, Dec 2, 2016 at 12:13 PM jimlux <jimlux at earthlink.net> wrote:

> On 12/2/16 8:51 AM, Attila Kinali wrote:
> > On Fri, 2 Dec 2016 08:05:17 -0800
> > jimlux <jimlux at earthlink.net> wrote:
> >
> >>> I'm measuring 0.350A with max cpu usage on all cores and the following
> >>> settings:
> >>>
> >> @ 5V, right, so 1.75W going full out.  That's a useful number to know.
> >
> > I once did an board with an i.m233 (arm9 at 400MHz) and it did less
> > than 0.5W IIRC. But I think this is about the lower you can do without
> > tweaking the OS.
> >
> >>> Apart from that I read somewhere that the beaglebones have terrible EM
> >>> characteristics. But I can't find my source so take it with a grain of
> >>> salt :-)
> >
> > Yes. The BBB is badly designed in this regard... The RPI is better there.
> >
> >> I must say, there are more of these things available in almost too wide
> >> a variety.. You could spend days going through all the datasheets and
> >> websites - I suspect that they ALL have about the same power consumption
> >> for a given amount of processing horsepower - same feature size on the
> >> die, after all - so it's more about peripherals and ease of use
> >
> > There are way too many, IMHO. And a lot of them are not usefull for
> > a lot of stuff or have very bad support. The Odroid are a prime example
> > of this. There is a "community" around them, yet getting them to do
> > anything usefull is a major pain. There is a handfull of companies
> > I know of, who do provide good support and those are the ones I am
> > usually sticking to (unless I have special needs).
> >
> >> And, it's more likely that idiosyncracies in the distros have been
> >> identified and it's more likely that the software will run on them after
> >> its built.
> >
> > It's actually better to go with a company who is invested in giving
> > you a working board than using something popular. Especially one that
> > cares to push all its patches upstream.
> >
> > Beside the mentioned Toradex, and Aries Embedded, there is also Olimex
> > which is known for it's wide variety of boards with good support.
> > Depending on your exact requirements, I would probably go for one of
> > the i.mx233 boards (the imx233 nano is quite neat) or A10 or A33 board.
> > Especially the i.mx233 is nice as it has an on-chip Li-poly
> charger/controller.
> > All you need to do is to supply it with 5V and it does the rest.
> >
> > A note of warning: a lot of the boards from Olimex have not enough ground
> > pins for the high speed singals they provide. If you are transfering data
> > with high-speed (several 10MHz) over the headerpin connectors, you will
> need
> > to add some additional ground connections.
> >
> > What are the exact requirements you have? How much computational power
> > do you need? How do you interface the sensors? How many boards will
> > you need? Is it out of question to build your own processor board using
> > one of the ARM9's in QFP? What is your budget?
>
> We're processing several thousand samples, received over a serial port
> or USB in a few seconds.  The algorithm (in Matlab, hence the need for
> Linux) grinds for around 30 seconds to produce the output.
>
> we're not sensitive on the "board cost" - labor to design a board is
> expensive, so a board that has low power, and the right connectors, so
> it's <1 day to make cables, etc. is a better deal than several weeks to
> design a board and spin it, etc.
>
>
>
> >
> > The reason why I'm asking the last two questions is, it is often more
> efficient
> > to do your own CPU board if you have to design a PCB anyways for the
> sensors,
> > need more than 10-20 boards and you can live with one of the "small"
> ARM9's
> > that come in QFP packages (like the i.mx233 or AM1705).
>
>
>
> That would come later, and be "someone else's problem" - We do the proof
> of concept, "demonstrate that it works in a relevant environment", and
> then it goes from there.
>
>
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