Ben and Arduino (again)

David Reyes Samblas Martinez david at tuxbrain.com
Sun Mar 7 20:29:08 EST 2010


Yes I know , I very overpost in this issue , but here I go anyway,
My intention is not program an arduino board(yet) ,the goal is to
exchange information between Ben and Arduino  to make able to interact
together (I also know SAKC is more powerful and "better" solution
technically to do anything than using this approch and I'm  also
including SACK it in my marketing master plan to conquer the world ,
so please avoid reply with "use SAKC instead" )

I plan to attend HARDMEETING 2010[1], on  20th to 23 of May l 2010
there a lot of Hacklabs from the territory than will attend or will be
tunned with this event , most of them are arduino lovers, so I want to
catch their attention on Ben, and also is the perfect excuse to push
myself in this personal challenge of interconecting both platforms.

I want to propose to the organization to do a workshop based on this
challenge, and prepare a clear and reproducible examples of different
approaches of doing so. Here is a draft , notes and calls for help.

1.- WIFI connection
This is my first approach, using a WiFi Arduino shield[2] I have just
received and the Spetec WiFi Card, this way arduino and Ben can
interact using http or a tcp sockets , I will do examples of both
cases, due Arduino can act as simply http server make a simply http
gui to access with links to light on and off some leds will be "easy",
and do massive data exchange between Ben and Arduino (read various
analog entries) will be done though sockets.

Pros on this approach:
Seems clear and  straight forward to achieve
Wireless is allways a WOW factor
I not need help make the demo

Cons of this aproach:
Price you need the shield and the wifi card all in all more than 100€,
the price of another ben or 4 arduino boards
Wifi shield is easily aviable, wifi card not.

2.- Serial connection (HELP!)
This should be the main way to achieve the goal of connecting both
platforms, is cheap a no need (almost) anything than wire and some
discrete components
Arduino has a very powerful an easy serial management, but Ben has a
"problem" due keyboard and serial sharing same gpio on RX(TP74),
Last news is than it only invalidates part of the keyboard , keys (FN,
ALT, SHIFT) and if it is the only problem I can also run a demo
advising this issue , and having the rest of the keyboard available
can be mostly useful for a lot of Aruino aplications, but finding a
work arround on this (using another test pad as RX?) would be awesome.
Any one with enough knowledge and free time to help me on this will be
very much appreciated.

The other issue is the different voltage of Arduino (5V) and Ben
(3,3V) but I found this can be solved using simply circuitery, this[3]
to rise from Ben to Arduino and a voltage divisor to low from Arduino
to Ben, due both are using TTL , any advice on this from the hardware
masters will be appreciated too, because I also see than because
rising the voltage is not nedede dua arduino recongnice the 3.3V as 1
in logic, so only the voltage divisor is needed.

Another incovenient I have workaround is the need of soldering to
access the pads under the battery, I have to test it yet, but instead
of soldering I have a plastic card with pads glued fitting  to the
serial pads on Ben and the cables are soldered to the plastic card
pads, all is thin enough to fit under the battery and the battery fix
and holds all together, also with a little forcing the back cover can
be closed, if it works using the serial console conected to the PC I
will make a post of how to do that card.

Once a serial connection is established between Ben and Arduino, using
minicom on Ben's end and programming Arduino to do something fancy on
Ben's commands should be "easy".

Pros:
Inexpensive and direct way to interact with Arduino.
Serial communication is the main way of Arduino to conect to
computers so arduino lovers will find it comfortable

Cons :
Mainly I have not damn idea of electronics, so a lot of thing can goes wrong.
Keyboard gpio issue
I have not seen any place what is the serial device on Ben's end, can
ben access serial console of other hardware?


3.-SDIO connection(HELP but no hurry)
Due I would preffer to use a serial approach this can be an
alternative, maybe for higher speed connections?,
I know arduino has shields to access SD cards, and there is also ways
to directly connect a card reader to Arduino [4]&[5], so one of my
guess if we can connect directly the arduino to the sd port of
nanonote and they can comunicate some way, as you might guess from my
way of explaining I have no Idea of what I'm talking about.
Again if some one has energy to waste in this challenges I would
peffert to be wasted on serial, but if serial was achieved and/or
someone finds more interesting this way , this sould be a powerfull
demonstration on how flexible is Ben in the demo.

Pros:
More elegant(remobable uSD) than serial (soldering or ugly plastic card thing)
More comunication bandwith? than serial

Cons:
Less damn idea than serial and unknown if there is even posible
Ben lost the sd port for other things like a sd card or wifi meanwhile
connected to Arduino

4.-Ethernet connection
This is so silly than i put in the lower priority in spite of is
totally achievable,
Arduino has a Ethernet shield than offers similar functionalities than
the Wifi shield, so the idea is stablish an http or sockect connection
between arduino an Ben , but due Ben is conected to USB to a PC host
to reach the network , the people seeing the demo will problably ask,
and why you don't us the PC host to connect to Arduino?
I have some Ethernet shields in stock so I have time , and at least 1
and 2 aproaches are fullfilled I will waist some time to use is as
joking no sense just for pleasure demo.

5.-Ethernet/Wifi Connection
The point 4 has open my mind to other approach Arduino with Ethernet
shield and Ben with WIFi, Price of Ethernet shield is lower than Wifi
one but we basically have the same pros and cons than the 1 approach
with the added handicap, that this will only work on wired LAN
eviroments with wifi enabled, the 1 approach can use and ad-doc
wifinetwork .

Now I'm finishig the examples of an Arduino beguinners workshop for
next saturday, but after then I will focuse on this due time limit to
present workshops proposals will be on  24th of April I will like to
know if I can count of help in improve the situation of the second
approach to make it viable to present a workshop where people can make
things with arduino and ben with no extra hardware.

[1]http://luzablue.org/hardmeeting/
[2]http://www.asynclabs.com/store?page=shop.product_details&flypage=flypage.tpl&product_id=26&category_id=6
[3]http://www.ucontrol.com.ar/wiki/images/b/bb/E-s.ht20a.jpg
[4]http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1206874649/135
[5]http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1259789744/0#0
-- 
David Reyes Samblas Martinez
http://www.tuxbrain.com
Open ultraportable & embedded solutions
Ben NanoNote, Arduino, Openmoko
Hey, watch out!!! There's a linux in your pocket!!!




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