[HH] Arduino and Raspberry PI

[markw at mohawksoft.com]

> markw at mohawksoft.com wrote:
>> The Raspberry PI has a good amount of processing, but lacks the I/O
>> to do what the arduino can do.
>
> Not disagreeing, but what sort of I/Os have you wanted that it didn't
> have?

For it to work in an "embedded environment" it would need a few PWM lines,
a few ADC lines, interrupt enabled digital lines, etc. Very similar to
what the Arduino has.

Yes, absolutely, you can "buy" these as add-ons, but that sort of defeats
the purpose. As it is, general purpose digital I/O boards for the PC are
practically obsolete from the Arduino. A $25 USB interface card can do
what most $50~$120 I/O cards can do, but with the addition of some
on-board processing make the arduino hard to beat.

I originally saw the PI as an arduino killer, but I'm not sure. I can buy
a micro-itx motherboard that will boot off a USB stick for $89. It will
have 100X more processing power than a PI, with more I/O especially if it
has a old printer port and PS/2 ports (mouse/kbd). Its bigger than the PI
but not that much in real terms when all the needed components are brought
together.

On one hand the PI doesn't have the I/O for a control platform and on the
other hand, it doesn't have the processing power for a computer intensive
platform. I doubt it has the horse power for more than one USB camera. The
network adapter in the PI is USB and and only 100mb! It doesn't even have
wireless, so that would have to work of the single USB channel as well.

So, I will need to think of a project for it, but I am sad it is so
limited. Because all of its non GPIO I/O is via a single USB 2.0 channel,
it won't even make a usable NAS or embedded router/firewall.


>
> While you can add I/O expanders, like the Gertboard (see list archives),
> last I saw pricing it was $46, so it adds significantly to the project
> cost.
>
> You would think they would have beefed up the native I/O on the Pi,
> given it was made for hacking, but I guess the educational projects they
> envisioned for it didn't involve that much low-level hardware
> interaction, or at least not enough to justify impacting their $35
> target price. (Their vision seemed to be more about letting each kid
> have their own computer on which to hack software. Not so much about
> hardware interfacing.)
>
> The interesting thought experiment is what would it have added to the
> price to make the Pi Arduino shield compatible, as you suggest. For a
> little bit more product cost, it would reduce the cost of expansion.
>
> There are other ARM-based boards with better I/O and similar performance
> capable of running a full Linux, but you'll pay more than $35, and
> you'll have a much smaller supporting community.
>
>  -Tom
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