Cheap wireless 2 way communication?

Im looking for an easy, cheap way for arduinos to communicate with each other. An rf link would be good, but unfortunately its only 1 way. Any ideas?

You can buy just a receiver transmitter pair that would work one way. the challenge is that cheap and easy don't always go together.

The Xbee is one of the most common RF transceivers used by hobbiest. While it isn't very cheap, about $45 for a pair, it is very easy.

The other option is that you can get a TX/RX pair for about $10 but you might find it much more difficult to make it work.

Check out http://www.sparkfun.com/categories/79/ as a place to start for info. They have a nice range of products through various frequencies.

Basically, it will be 2 arduinos, each with a button, and a buzzer and LED to signal when it is pressed. when one button is pressed, that arduino's buzzer and led will go off, and it will send a signal to the other arduino to block its buzzer from going off for a few seconds. (if anyone has a different approach feel free to post)

I was looking at Xbee, and for now it seems like the best option. It has to be 2 way, so the reciever/transmitter setup wont work.

Also i want to keep the size low so im using arduino nanos. Will there be any issues connecting the Xbee directly to it? I want to skip the bulky sheilds.

The nrf24l01+ seems pretty awesome for low-cost high-speed two-way communication: http://iteadstudio.com/store/index.php?main_page=product_info&cPath=7&products_id=53.

Its a 3.3V part with 5V tolerant I/Os. It uses the SPI protocol for high speed communication, up to 2mbps. Range is 50m to 70m.

That seems like a great solution! Im still pretty new to arduino, so im sure it will be a challenge to get it to work. Do you know if the coding is similar to the Xbee? (ie could I use an Xbee tutorial for this?)

Here is a very low cost option: http://arduino-direct.com/sunshop/index.php?l=product_detail&p=188.

gontgont:
That seems like a great solution! Im still pretty new to arduino, so im sure it will be a challenge to get it to work. Do you know if the coding is similar to the Xbee? (ie could I use an Xbee tutorial for this?)

I think its easier than XBee. You just need to set the Tx and Rx addresses the opposite on each radio, turn on the auto-ack feature to ensure reliable messaging, and its good to go. You don't use the serial port to send and receive, you just call a function to send (up to 32 bytes at a time), and when a message is received you call a function to read the received data into a buffer.

The Mirf library is a bit basic, but it does the job.

If you want long range make sure you buy one with the amtenna adaptee not jist the onboard antenna, ebay has all kinds real cheap

There are these

http://shop.moderndevice.com/products/jeenode-kit

which I have not tried yet but I'm gonna soon.

The 5$ nRF24L01+ looks great, but I couldnt find any tutorials for it. Can anyone link me to one? As for now, I think ill get a pair of Xbees because there is a lot of support for it, and i can get the cheaper pair for future projects after I learn a bit more about transmitting and receiving data.

Its really simple once you do it, change a byte buffer and send, and recieves that buffer back if available with new data
I have some examplrs if u want

http://arduino-info.wikispaces.com/Nrf24L01-2.4GHz-HowTo

The nRF24L01 modules are well supported. There are 2 Arduino libraries for it, the Mirf library which you can find on the Arduino playground and Maniacbugs RF24 library which is a bit more advanced. Getting Started with nRF24L01+ on Arduino | maniacbug Maniacbug is a member of this forum. I have a bunch of these modules and they are not that difficult. I had zero programming experience until 3 months ago, but I did manage to control a remote rc car last month with a pair of nRF24L01 modules.

Alright trying both wont hurt. Thanks everyone

The cheapest works at about 2cm using 1 led and 1 resistor for each unit and it is wireless.

This is actually very serious stuff as reading the white paper will show:
http://www.merl.com/papers/docs/TR2003-35.pdf

Interesting, but im going to need something with a bit bigger range than that

One more thing: The Rf transceivers and the Xbees run on 3.3V, and Ive only ever worked with 5V before. Is it the same? Can I use both 5 and 3.3v or do I have to stick with one? The only thing that would use 5V is a button, other than that I have an LED and a buzzer, which run from the pins. Can I just use 3.3V for it? Keep in mind that ill be using an arduino nano

The NRF24L01+ (or NRF24L01p) is powered with 3.3V, and has 5V tolerant I/Os. So you can hook it up to a 5V arduino without any problems as long as you connect VCC to 3.3V. The older NRF24L01 is not 5V tolerant and would need level shifting support.

That makes things much easier, I guess i wont be going with the Xbees at all then.