[Chugalug] Raspberry Pi, and how to start X automatically

Dan Lyke danlyke at flutterby.com
Mon Oct 22 21:49:02 UTC 2012


On Mon, Oct 22, 2012 at 11:11 AM, James Nylen <jnylen at gmail.com> wrote:
> 1) Buy an Arduino + Ethernet shield, and connect sensors to it

I think this is a totally reasonable solution, it'll just cost more(!)
than the Raspberry Pi. Which was kind of my point: I love Arduino, I
was working with Atmel AVR chips before Arduino, and think the
architecture rocks and all that. Nothin' against it.

I have a number of Arduino and AVR devices at home, and for one-offs I
will be deploying them before I buy a Raspberry Pi because the
limiting factor is round-tuits and I already have way way too many
"Oh, that'd be cool to play with" hardware devices cluttering my
desk(s).

It's just *amazing* what you get in the Raspberry Pi.

> 2) Buy a RPi + some kind of add-on board for connecting sensors (as far as I
> can tell, several are in development, but Arduino is a more mature platform
> for connecting stuff to the real world)

Yeah, the block diagrams for the Raspberry Pi show a GPIO header on
the board, I suspect that you'll be able to either memory map those
and access them as something running root, or get to them via
/dev/gpioXXX.

I don't know what temperature sensors you were planning on using, I
suspect that GPIO is just simple digital, which means you'd probably
go with something like the 1-wire devices, if you needed an ADC then
it becomes tougher.

> The fact that I would still have to buy an add-on board for RPi seems to be
> a good argument in favor of using Arduino.

I think you're totally on-track, it's just that I've seen this
"Raspberry Pi is overkill for" meme a couple of times, and I just want
to point out that Moore's Law has caught up with the AVR architecture
Arduino: I bet the Raspberry Pi doesn't use any more power, and in
quantity 1 it's cheaper...

Skipping backwards in your email:
> Anything more rich (like presenting a web front-end) would be handled by
> a program running on a real computer with a real web server.

A handy trick for JavaScript security issues: reverse proxy server on
your main server. I've used this for a couple of things to punch a
hole here or there to some limited facility device in an otherwise
rich web page.

Dan


More information about the Chugalug mailing list