100% Newbie to this -- first project -- need help

Hi. i am in year 7 (aka 12 years old) and am thinking about embarking on a project. i have just learnt C Programming and wonder, for starters if i can program an Arduino with this. Anyway, the project i am thinking about doing is an X,Y Plotter. it has a pen attached to a few servos and it plots depending on the co-ordinates entered in the program. I need to hook up 3 servos which will be hacked to become continuous rotation motors and a web-cam to align the pen with the grid paper. The machine will be hooked up to a computer/laptop and i need a joystick to link up to the Arduino so the pen can be controlled "freehand". i am really confuzzled :~ about what to do and just need a heads up on how to do this and if it is actually possible, as well as if i need any extra knowledge/software.

Thanks in advance and sorry for the essay!!!

My advice: work first through the tutorials on the Arduino.cc site, also on the playground there are some smaller projects which are usefull to master before building a complete plotter.

second, alignment with a webcam will not be trivial, I would recommend to do that in a follow up release of the plotter.

do the tutorials tell me how to design the circuit? thanks though. i really appreciate the advice. what type of arduino should i get?

do the tutorials tell me how to design the circuit? t

If all you're doing is using R/C servos, there is no circuit to design; the Arduino (I suggest an Uno to begin with) can connect directly to R/C servos.
I second what Rob said about the webcam; later, much later.

i want the servos to work on their own depending on parameters set by the user, in other words the co-ordinates.

I am very impress that a 12 year old go into this hobby call the Arduino. You will discover a lot of cool things to do with the Arduino. I don’t know about your electrionics, construction and programing skills. That particular hobby have a lot of “self learning” not like school that you have a teacher to show you how. A least, in school, you lean Math, that you will need that knowledge in this new hobby call Arduino.

About your project, it is possible. Use 2 servos, combine with a joystick. One servo for X axis, One servo for Y axis. A pen holder, use the Arduino UNO is OK. The joystick is 2 potentiometer type ( X-Y) ← A what ??? Ok, you know about the joystick in a GameBoy, or a X-Box. Those joysticks use a switch type ( push button type ) a North, East, West, South buttons. So you need one of those “flying” joystick use in a flying simulation game. Those type of joystick are a bit “old”. they are call Analog Joystick. For the moment, you can use 2 regular potientiometer of 50 K should be OK. So one pot will be X and the other is Y.

I hope you understand. Anyway, this is just a basic X-Y plotter.

in terms of my construction skills, i made a robot (which worked) on my own using lego mindstorms and am alright with C. I have completed a series of kits http://www.jaycar.com.au/pdf/scct1.pdf and http://www.jaycar.com.au/short_vol02.asp so my electronics are decent. With the servos, i plan on three because i want the ability to be able to lift the pain so that you can, say, space out letters instead of magically joining them together. What is the servo limit with the Arduino UNO as well? Sorry for the exam of questions too!

What is the servo limit with the Arduino UNO as well?

I know two will work well. But I don't know if you can control more than 2 servo.

what about a motor shield Motor Shield - Arduino motor/stepper/servo control ?

Zack - a motor shield is NOT useful or needed for a servo. Second post you have said that!

Making something out of Mindstorms Lego unfortunately counts a zero in the electronics experience stakes. You project is possible but only after you have acquired about another year of experience. And even then it will be challenging.