If there had been a failure of the RFM22 module, we'd see a complaint in the Arduino

Serial Monitor (making sure the baud rate is set to 9600). As it is, the "No reply, is

rf22_server running?" message lets us know that the sketch is running correctly, the

library compiled properly and the module is communicating properly with the Arduino.

Unplug this Arduino and plug in another one, with another RFM22 shield attached to

it, and load the "rf22_server" sketch onto that board. Launch the Arduino Serial

Monitor, and you'll note that there's no traffic at all. That's as should be; the sketch

only prints messages received from an "rf22_client" device. Now plug in the other

Arduino, the one that you already install "rf22_client" on, and watch what happens in

the Serial Monitor window.

As soon as the new Arduino comes online- not more than a couple of seconds- you'll

see a message start scrolling by indicating that the message "Hello world!" was

received, and that a reply was sent. If you open the Serial Monitor to the "rf22_client"

board, you'll notice a similar message:

That message displays the text returned from the board programmed with the

"rf22_server" example. Thus, these two examples show how to pass data back and

forth between two devices and how to respond when a message has been received.

For more information, check out the library webpage.

Important Legal Information:

The RF22 library downloadable from our site configures the RFM22 to operate at

910MHz. This is okay in the US and some other countries, but before you make

extensive use of it in projects, please check your local regulations to ensure that it is

not interfering with other local radio services. Note that the RF22 library as

downloaded from the library webpage at open.com.au configures the device to

transmit at 433MHz, which is not a generally acceptable frequency for use in the

United States.

Next steps:

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