[HH] Hacking Embedded Linux: More Hardware than You Require

[Tom Metro]

> When: May 16, 2012 7PM (6:30PM for Q&A)
> Topic: Hacking Embedded Linux: More Hardware than You Require
> Moderators: Federico Lucifredi
> 
>         Ranging from Plug Computers to bare development boards to
> miniaturized systems and rooted hard drives, the bestiary of ARM devices
> at our disposal for projects is ever-growing and marvelous to explore.
> 
>     A detailed review of the features, capabilities, and limits of a
> number of low-cost platforms available to experimenters, in disparate
> form factors and powered by different chip vendors:
> 
>     Sheeva Plug, Guru Plug, Dreamplug (Marvell) BeagleBoard, BeagleBoard
> xM, Pandaboard, and BeagleBone (Texas Instruments) i.mx53 Quickstart
> (Freescale) Gumstix boards Raspberry Pi Cotton Candy Computer Hacked
> Hard Drives ...and more.

Nice talk Federico. Some follow-up questions...


You've explained what you use the network printer for, and a bit about
the WD NAS, but you've never really mentioned what you use all these
other devices for. I presume at least some of these you aren't simply
acquiring to show off in talks, and that you actually have projects in
mind for them. What were you using them for?


You made a comment that you ordered clear plastic enclosures for the
Pandaboards (I think) for your "team." What team? My understanding is
that this hardware was a hobby and not related to your day job.


I think it is worth noting that the BeagleBoard started out as an eval
board for the TI OMAP CPU, unlike say an Arduino, which was created
independent of the CPU vendor. But it is interesting that they made the
hardware open and this has potentially contributed to its popularity.

I assume the Freescale board is similarly created to show off a
Freescale CPU. Is their board design open? Are there any 2nd sources for
this design with a SATA port? Do you know if the SATA port is compatible
with port multiplexers?

I'm not sure where Pandaboard fits in. I'm guessing this is driven by a
board vendor rather than a CPU vendor. What CPU does it use? (You said
it was comparable to the BeagleBoard, so I assume an ARM variation.)

You said the Sheeva Plug and related computers were not open hardware.
While technically true, the Sheeva Plug is a reference design to show
off the Marvell system-on-a-chip, with the first Guru Plugs being
derived from it. Presumably anyone who wants to make plug computers and
is buying the chips from Marvell can probably get the design for little
to no cost. The documentation (schematics) may even be freely available.

Also, on the topic of openness, you should note that the Raspberry Pi
isn't an open design, and uses a proprietary CPU, possibly requiring
proprietary binary-only kernel drivers.


> We equip the attendees with all the necessary knowledge to integrate a
> small computer system for the embedded field application of their choosing.

Well, not quite. It was a pretty quick run through of the hardware,
though understandably you had time constraints.

It would have been interesting to see something like a live demo of a
"hello world" application on two platforms - one on the simple end, like
an Arduino, and one running Linux, like the BeagleBone.

As you pointed out, developer time is valuable, so understanding what
complications and tradeoffs exist on the software development side also
factors into the selection of an embedded platform.


You asked about macro video capture. I could have sworn you had a
working setup for that at the prior presentation you did for BLU. I
thought you showed live images of items that appeared to be under a copy
stand. I guess that was just your desk lamp I saw.

I've seen modern day versions of the "copy stand" in computer catalogs.
Googling turns up the name "Visual Presenter":
http://www.google.com/search?q=Visual+Presenter&hl=en&client=firefox-a&hs=xME&rls=com.ubuntu:en-US:unofficial&prmd=imvns&source=lnms&tbm=shop&ei=yLe1T5q_FoXtrQe3rJXeBw&sa=X&oi=mode_link&ct=mode&cd=6&ved=0CJkBEPwFKAU#q=Visual+Presenter&hl=en&client=firefox-a&hs=7ME&sa=X&rls=com.ubuntu:en-US:unofficial&tbs=p_ord:p&tbm=shop&prmd=imvns&ei=0re1T-CQH8fQrQfiru3hBw&ved=0CCEQuw0oAQ&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&fp=132a64d40bad7efc&biw=1121&bih=763

For example, "Adesso NuScan 500 5.0 MP CMOS 2592 x 1944 Visual Presenter":
http://www.newegg.com/Product/Product.aspx?Item=N82E16838166018

which sells for $150. (Only claims to support Windows.) You can probably
build something cheaper yourself (you can get the old style copy stand
starting at around $50), but if you want something ready to use, this
looks like a good option for use in presentations.

Amazon has a fold-up portable version (no lights):
http://www.amazon.com/Portable-Scanner-Visual-Presenter-Pixels/dp/B005K47900/ref=sr_1_14?ie=UTF8&qid=1337309553&sr=8-14

and then there are a bunch of products that fall under the name of
"Document Camera", which are basically a web cam on a stand or goose
neck, like:
http://www.amazon.com/IPEVO-Point-View-USB-Camera/dp/B002UBPBTC/ref=sr_1_4?ie=UTF8&qid=1337309553&sr=8-4

Costs $70. Seems to have overall good reviews. Has autofocus, though a
review complains it doesn't work reliably. (Reviewers claim it works
with Linux.) Bunch of others like it.

 -Tom