Arduino wireless connection options whit other arduinos(mass production)

I wonder how can i connect my arduino systems beetwen each other using some sort of wireless connection(not wi-fi bcs of price, power consumption...). I was looking at RFID communications and discovered that some of the latest RF transmitters can reach up t 50 meters range, have low consumption and also arent expensive.
So i would like to hear some of your experiences whit using RF on arduino projects, or if you have a better alternative.

Also im wondering if i would be later able to use atmel AVR+rf sensors(whithout lots of other chips) in the final design for mass production, becouse final board needs to be as smallest as possible and have low energy consumption(final boards will consist of an AVR, rf sensor, mini speaker and a LED).

Thanks in advance for infos.

What RFID can communicate up to 50 meters? Never come across that and I used to design them for a living. Long range and low power consumption do not sit well together.

What sort of numbers do you mean when you talk of mass production? I would not consider anything under 5,000 as that.

For anything over 20 units I would be designing my own board and not using an Arduino, in fact I often use a stand alone arduino design for one off.

You have to describe the sort of communication you want.

The ESP8266 devices provide WiFi at low cost.

An NRF24 2.4GHz transceiver is an even cheaper option.

InfraRed would also be a cheap possibility if the data rate is low and the physical environment is suitable.

But the most important decision is the communication protocol and WiFi may help with that. Do you want one-one or one-to-many communication? Do the individual devices need individual IDs ?

...R

@Grumpy_Mike Sry, i meant RF in general, not RFID in particular.

@Robin2 thanks for info, i wil lcheck it. I was thinking of using the RF technology similar to the one in RC toys controlling.

Im plannig production of around 400 units, so i need to develop custom circuit to achive minimum costs.
Basicly comunication will go like this:

portable small circuit whit peripherals(5x5cm max), several individuals of them inside a house(1 to 5 circuits)
this will receive(not transmitt) wireless signals(rf or wifi) from a docking station
docking station will connect to smartphone software via wifi cnnection(thank robin for infos), and will contain bigger main microcontroller(arduino).

The smaller circuits needs to have individual tags(IP or smt).

In fact i will send data from my phone to the docking station, and that station will send individual signals to tha small portable circuits to turn on speakers or LED on them.

klemko:
The smaller circuits needs to have individual tags(IP or smt).

In fact i will send data from my phone to the docking station, and that station will send individual signals to tha small portable circuits to turn on speakers or LED on them.

I have built a system a bit like this for Radio Control of my N Gauge model trains. The Deltino devices I used are roughly equivalent to an Arduino with an NRF24 and a h-bridge. My "master" unit is connected to my PC which has a browser-based GUI to control the trains. The Browser can also be viewed on my phone. I guess you could use an Arduino with an ESP8266 as the master and communicate with it from a phone using WiFi.

You could include code in the slaves for receiving an ID number and storing it to the EEPROM.

...R