On Tue, Mar 16, 2004 at 07:59:17AM +0000, Arron McLaughlin wrote:
> Hi there,
> I'm 14 years old and for a science fair project I'm making a personal
> organiser. I am fluent in C and asm, but I haven't worked much with embedded
> hardware before.

Cool. At 14 I was still playing with 555 and counters.

> The organiser needs plenty of eeprom memory for data storage and enough rom
> to contain programs to power the 16x2 lcd, keypad, a few small applications
> and a scientific calculator.

Probably overkill for a science project. Pick 1 application to implement.
I would suggest something like a postit note jotter that does the following:

1) Allows you to type a subject.
2) Then you enter a quick note.
3) List by reverse time/date or entry order.

One last thing that may be interesting is form in addition to function.
One of my students worked out a project that implemented a chorded keyboard
using switches so that you could input information with one hand by
entering combinations of switches. A couple of quick searches came up with
this pretty good overview:

http://www.lsi.usp.br/~jecel/merlin4.7/chord.html

and this gallery of chorded keyboards:

http://tim.griffins.ca/gallery/keyboard/chord.html

You could build just as interesting a project by simplifying function but
adding a cool form.

> Which brings me to my questions..
> Has anyone done something similar?

As I said one of my students did this type of work. It was several years
ago with a 16F84, but the concepts are the same.

> What pic should I use?

I think everything could fit in a 18 pin PIC as long as a 4 bit interface
is used for the LCD. Personally I'd recommend the 16F88 because it has
sufficient memory, nanowatt technology which means that it can be easily
made battery conscience, and doesn't require an external oscillator, and
most importantly is self programmable, so you can store your notes on chip.
But even if you wanted to use a serial EEPROM, it implements i2c so it
would be trivial to add a hefty serial EEPROM and store a ton of notes.

For example you can order a 16F88, and a 24LC256 32 kbyte EEPROM from
Randy Jones at www.glitchbuster.com and barely crack $7 USD including
the shipping.

> And, is there a pic available which is powerful enough and has enough i/o to
> control both my lcd, 5x4 keypad?

See above. Also think about the chorded keyboard idea.

>
> Your help would be really appreciated as there isn't much support available
> at my school.

Be sure to read Wouter van Ooijen's getting started with pics page:

http://www.voti.nl/swp

and my PIC pages with has an overview of quite a few different items
including my Trivial PIC programmers:

http://www.finitesite.com/d3jsys

Hope this helps,

BAJ

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