Hello everyone..
I'm just a beginner in the world of Arduino.
I'm always advised to get started with Arduino Uno but I wonder that why not to choose Arduino Nano (it's compact, small, cheap and can do almost as on Uno)
So what are advantages of using Uno over Nano :
There are two flavors of Uno. One has a Surface Mount processor and the other has a Dual Inline Package processor. The DIP is easily replaceable if it is damaged. The processor in the Nano or SMT Uno are not easily replaceable, so for a beginner the DIP Uno is recommended. That said, Nano clones can be had for near the price of a bootloaded Mega328 so I guess it comes down to what you want to do with the board.
An UNO will accept shields.
Functionally they are the same. I went with nano's for the same reasons you listed in the OP.
I use prototyping breadboards to hook things up and it works out beautifully.
interestingfellow:
Functionally they are the same. I went with Nanos for the same reasons you listed in the OP.I use prototyping breadboards to hook things up and it works out beautifully.
Likewise.
Breadboards are the way to go.
Or indeed Pro Minis with a USB-TTL adapter; you remove the adapter when it goes stand-alone.
the 328 chip comes in many flavors.
the DIP has 6 analog pin. the SMT has 8, the nano uses the 8, not so the UNO
UNO
+accepts shields
+power connector
+pin 13 / on-board LED is controlled by FET or transistor. no load
-6 analog inputs
-odd pin spacing, cannot use on a standard board
~ wide form factor, better for a bench
NANO
+8 analog inputs
+standard pin arrangement, can plug into standard boards
~narrow form, better for smaller projects
as for the argument about DIP vs SMT.
328 chip $3.70 plus shipping from digikey or mouser
NANO $3.70 on EBAY free shipping.
to me that argument is moot.
dave-in-nj:
to me that argument is moot.
As you will note, I am forever advising people that designing your own PCB with the processor and support components is an exercise in futility unless you plan to go into large scale production. And I mean large.
Nothing wrong with making a PCB, just use the Nano or Pro Mini as a module footprint and mount with header pins (either soldered or socketed, as the need arises).
From my personal experience I suggest you a Arduino Uno,
I 1st picked a Nano and was a big mistake, 1st because there is a lot of clones and 20% of the chines clones don't work 2nd because Nano is easy to damage and as a beginner I was really sad that I damaged my Nano so fast.
My 2nd arduino is Arduino Uno with the 328p chips on board (not smd) they are the best, easy to plug and play on a prototype board (breadboard) and easy to replace or unplug the chip for homemade projects.
Don't forget, buy extra jumper cables, big (not small) breadboard and a set of leds, resistors and 6mm buttons.
A perfect way to start.
Domino60:
From my personal experience I suggest you a Arduino Uno,
I 1st picked a Nano and was a big mistake, 1st because there is a lot of clones and 20% of the chines clones don't work 2nd because Nano is easy to damage and as a beginner I was really sad that I damaged my Nano so fast.
Wasn't you big mistake in your wiring ? rather than your purchase ?
I have had no failures of boards not working. only reports of others who have found boards are not working.
but, your premise is that the only possible option is to buy either a Arduino, branded and supplied UNO or a chinese clone ? or that clone uno boards have a zero failure rate ?
if you get official boards, your failure rate should be zero. UNO or NANO.
if you buy either an uno or nano from e-bay, your failure rate should be about equal.
as for what is easier to damage, that too is equal. you short out the power supply and presto, you shorted out the power supply. ditto for pins. I cannot see how the UNO would be able to take any more or less abuse then a NANO or vice-versa.
Every board I have purchased, UNO and NANO and Micro, have come pre-tested, with the boot loader and pin13 LED with a blinking sketch loaded.
Since the lead time to get a new board from e-bay/china, is 3 weeks or more, if you go that route, get at least 2. that way if you blow one up, you have a spare.
on the premise that you will blow up the DIP and then be able to replace it, logic would state that one should have a spare DIP on hand. that chip alone would incur a cost of more than double a clone with free shipping.
A year ago when even a clone was $15, I would have agreed to get the DIP version. today, I would re-think that.
Wasn't you big mistake in your wiring ? rather than your purchase ?
To be honest yes, as a beginner in the past I didn't knew much about arduino but I was exited
what you can do with it, I start experimenting with it without reading the necessary instructions 
You know the game which you enter and don't accept to follow 1st the tutorial and you start play don't knowing what to do and how to play, pressing everything to see what you can do.
That's was my mistake, another thing is that mostly chines closed come already damaged or bad soldered,
I had that kind of circuits from china (ebay..etc).
Domino60:
1st picked a Nano and was a big mistake, 1st because there is a lot of clones and 20% of the chines clones don't work 2nd because Nano is easy to damage and as a beginner I was really sad that I damaged my Nano so fast.
Nevertheless, this is nonsense.
The only advantage the UNO has is a polarity protection diode on the "barrel jack" which of course, the Nano does not have. If you connect the power in reverse to VIN on a UNO (which would be the most common cause for actual damage), you will do every bit as much damage as on a Nano.
It was your ham-fisted work that did the damage, nothing to do with the board. To assert that "20% of the Chinese clones don't work" suggests that you have a problem, as this is not the experience of the rest of us here.
Get both.
one thing not mentioned is that the official boards come with an FTDI chip. The lowest cost ones come with a chinese version that requires a chinese driver. if you use Linux, you have it, if you have windoz, you have do download it.
if you broaden your range, you might even look at the mini. you are too new to know about the BasicStamp. it was all the rage 10-15 years ago, but at $30 a pop, it was krazy expensive. the mini is a drop in pin-for-pin replacement. that means the pins have a rather odd location. it is a drop in replacement with it's pins an order of magnitude stronger than the POC tinfoil pins on the Stamp.
the NANO wraps pin 13 'around the block' to the other side of the board, but other than that it is much closer to the pin layout of the UNO.
A suggestion I would have is that you get a board that has a USB connection and can be programed with only a cable. the USB chip is not that big a deal but having to use a separate board to connect in order to program is a PITA.