I am completely new to robot making. I want to know the difference between an arduino and any other cpu. How is it different and which one is the best to buy. Somebody please guide me...
No MCU can drive motors directly. Motors draw too much current. That is why all robots need motor drivers. There are some controllers and development boards that have motor controllers built in.
Some Picaxe development boards include a motor controller.
There's the ubotino from Ro-Bot-X and motoruino from GuiBot. Both these boards were designed by LMR members and are for sale. Both boards have motor drivers. Neither board has a USB interface built in. They require a FTDI / USB cable or interface to be programmed.
I have also designed 2 controllers with motor controllers. My controllers have the USB interface buit in. The original Magician controller was designed to be a low cost unit for the classroom. It has reverse polarity protection and the new version is rated at 1.5A per motor.
Now my newest controller the Micro Magician is even better. It has a FET motor controller, 3 axis accelerometer and IR receiver built it.
The reason for the astrisk is due to the fact that IF you could find motors that stalled in the 20 to 30 mA range you MIGHT be able to run them directly from an arduino. I am fairly sure that attempting to run any motor directly from an arduino pin would still be frowned on due to back EMF. Servos are easily run from an arduino without a shield. I don't believe there are any true restrictions on what pins can be used. You would only require a data pin for the signal pin on the servo and then power and ground. If you were to use an arduino board, you would be limited to the amount of current the onboard voltage regulator could supply unless you bypass the regulator to supply power to the servos.
Well thanks to both of you. Just clear one more doubt, if I somehow bypass the power to a servo, will a continuous rotation servo be as good as a motor. I am an absolute beginner by all means. I'm just out of school and even though I've done nothing yet, but maybe in a month and a half, I will be able to start my first project. I'm asking you these questions because I want to build my bot from the basic as I want to learn the basics and also as I have no financial backing and my parents won't help me out.
Chuckcrunch built both of them.
http://letsmakerobots.com/node/30618 The China Syndrome
I am sure there are other examples. These are just two of the most recent that I can recall.
Whats your background? Have you done any programming before?
If not then you are probably best to start with picaxe. It uses the basic programming language and there are heaps of projects here including the start here robot for you to learn from. Picaxe is a system like the arduino except it uses Microchip microcontrollers.
If you have had a bit of experience with c/c++ then perhaps you are better to start off with the arduino system. Huge amount of support both here and throughout the web for it. While it is known as arduino the actual chip is an atmel atmega328 chip.
Although the line is blurring between microcontoller and cpu both the picaxe and arduino are microcontrollers not cpus.The major difference is microcontrollers are quite a way behind cpus in processing power but they have extra hardware functions internally that reduces the amount of external componentry necesary to build a project.
Yeah, I have a background of C++. That's the reason why I raised this question about arduino. Thanks for clarifying. Can you help me a bit further- please give me the url of some sites where arduino micro controllers are available and they can deliver in India. Most of the sites mentioned here on lmr don't deliver in India. Thanks in advance.
Have you looked at Yourduino. That is the lmr shop. I imagine they'd deliver to India. There is a link to it at the top of the page.