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Hi everyone,
I'm new to Arduino and to this forum.  Hope this is the right place to seek help for a utter noob such as myself.
Trying to design a simple controller but kindda lost as of where to start (Yes, I've done some reading).  Short listed some items.  Can someone help me go the right direction.  (I can do some basic C/C++, should be able to pick it up in a short time)  Should I work with the Uno (seems like it does'nt have enough I/O)?

Requirements (prototyping purpose for now, may mass produce if it goes well):
1.  LCD display and basic keypad (may get the DFRobot LCD Keypad Shield)
2.  Input from pizeo resistive pressure sensor(currently 4, but may need up to 16): converted to voltage.
3.  A way to save the data recorded.
4.  A way to export the data, thinking of SD card or bluetooth tx (or both).

Can someone kindly give me some recommendation?  Was deciding between going Arduino and the PIC microcontroller way.  Decided on Arduino due to really available shield.  I'm on window 7.  Since I going to start fresh, would programming in C# be a better learning path?

Thanks alot to all the help in advance.  (Do kindly point me at the right forum if this isn't really a place for beginner:))
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IMHO... this is 'the' Arduino forums.. so yes, help is supposed to be sought here.

That being said..  dont let the attitude of some of the 'members' here get to you... 
some people forget where they came from.. or what it was like to be new & learning..   and they are only capable of providing help if you do things/post in certain ways that appease them.  (instead of helping the beginners on what is pertanent information or how to post better)

my advice is just ignore those people..  and keep your chin up.. there are more, helpful members here that will read your posts and try to help with you have.


As far as what Ardiuno to get.. only you can answer that as you know your project.. if you need more I/O pins.. try a mega vs uno..


#3 & #4 could both use an SD card..

While maybe not specific to YOUR project/needs...

I suggest going through some of the basic tutorials, so you get familiar with common tasks & terminology..  (which is big around here)

http://arduino.cc/playground/

I also really like/enjoyed:  http://tronixstuff.wordpress.com/tutorials/

he did a GREAT job in covering many common projects and documenting it!

good luck!

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Since I going to start fresh, would programming in C# be a better learning path?
I would say not. Not that you have a choice if you are going to go with an arduino.

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2.  Input from pizeo resistive pressure sensor(currently 4, but may need up to 16): converted to voltage.
Not too sure what you are expecting here there is no such thing as a "pizeo resistive pressure sensor", the common pizeo sensors are voltage generators not resistive and they only give an output when the pressure on them changes, so there is no constant output.
For 16 analogue inputs you need either a Mega or a Uno with an analogue multiplexing chip on the front end. There are lots of examples of this. 

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3.  A way to save the data recorded.
How much data, each Uno has 1K of EEPROM you can use.

Quote
4.  A way to export the data,
Simplest way is to use the serial link that is already built in. Transferring stuff to the main computer is quite easy. Processing is a popular language to use.

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Do kindly point me at the right forum if this isn't really a place for beginner:)
Beginners always welcome here, especially if you are willing to learn. If you just want people to do stuff for you like homework assignments then there are less people willing to do that, but their are some.
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Thanks for your reply everyone. 
Needed a kick start at the right direction.
I've decided to go Mega.  Will work from there, thanks a lot.  Cheers
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@ Grumpy_Mike,  oh yah, forgot to mention, there is peizo resistive pressure sensors (may be called FSR in some product). Eg http://www.tekscan.com/flexible-force-sensors
Advantage of it is that its thin and flat as paper.  My intention was to place it in shoe sole.
Unfortunately I need an op amp to convert that to voltage (shouldn't be an issue).  Only problem is that I'm afraid it will break easily.  Seems like its on some professional gait analysis device (I may be wrong).

Thanks again for your advice.
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Meh I think it would be ok. What is its intended use? Just out of curiosity.
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there is peizo resistive pressure sensors

Well there is a :-
"there is piezo resistive pressure sensors"
sure but a
"there is piezo resistive pressure sensors"
No

Read up on what the piezo effect is here:-
http://en.wikipedia.org/wiki/Piezoelectricity
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Based on what I have read today, the use of the term piezo effect, albeit a common one, appears to be a bit of misnomer, as piezo means nothing more in this case than the application of pressure. It's possible that I am missing something in the context of this conversation, but it seems the current statements would be confusing to those coming to this thread looking for information.  I know it was confusing to me so I did some reading and I offer the following links for those wanting to do the same:
http://en.wikipedia.org/wiki/Piezo
http://en.wikipedia.org/wiki/Piezoelectricity
http://en.wikipedia.org/wiki/Piezoresistance_Effect
http://en.wikipedia.org/wiki/Piezochromic
http://en.wikipedia.org/wiki/Piezomagnetism
http://en.wikipedia.org/wiki/Piezooptic_effect
http://en.wikipedia.org/wiki/Piezoluminescence

Please note that I can't vouch for the validity of these links, it is after all  wikipedia, nor are they all directly related to the discussion at hand. They are just some of the information I came across while attempting to get a better understanding of all things piezo related.

Sorry for the hijack.

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Well in the Piezoresistive effect page it does say:-
Quote
This section's factual accuracy is disputed.
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I've been playing with piezo discs, they're fun but at $1 each I think that cap sense or conductive foam is cheaper.

I think of piezos as capacitors that you can change the charge through mechanical pressure. To that end, a piezo with a little resistance can be a kind of touch R-C circuit which is what I've made work and read using a digital pin and watching the time to drain from HIGH to LOW.

I saw one site linked to here, they use a piezo to vary a 2.5V current to sense the disc being blown upon. The circuit is good for sound detection which I'm more interested in. Seems to me that the circuit would also be good for zero-crossing detection. My own through-diode-and-transistor circuit is crap compared!
http://www.dtic.upf.edu/~jlozano/interfaces/blow_sensor.html

BTW, those force-strips are freaking expensive! I know there's alternatives including piezo discs. Check into how an electronic scale works some time.


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Examples can be found in your IDE.

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Meh I think it would be ok. What is its intended use? Just out of curiosity.

I intend to implement the pressure sensors into a shoe to monitor the pressure on the foot during walking for a bio-mechanical project. Very much like this http://www.tomorrow-options.com/en/walkinsensesports.
I believe such pressure sensor is also use for the upcoming Nike+ basketball / training http://www.coolhunting.com/tech/new-nikeplus.php 

The standard piezoelectric sensors I've seen is not suitable to place inside a shoe sole due to size and durability.
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Well in the Piezoresistive effect page it does say:-
Quote
This section's factual accuracy is disputed.

The only thing that is disputed is whether metals are subject to the piezoresistive effect or not.
Reading the entire discussion, including the linked pages, results in a much more informed opinion.
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What if you put piezo disks -into- the sole of the shoe? Then you could read from different parts of the foot.

All conductors and semiconductors (that I know of) do change resistance (however slightly) when physically stressed. And when temperature changes (emphasis on slight in certain temperature ranges, more in others) and probably under other conditions as well.

Piezoelectric effect is not piezo-resistance.

Quartz is piezoelectric as is bone and sugar crystals (yup). A piezo lighter generates a 1500V spark to light the gas.

AFAIC, Grumpy Mike used piezo-resistance with the conductive foam under the floor tile thingus.
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Examples can be found in your IDE.

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