O'Reilly logo

Building Wireless Sensor Networks by Robert Faludi

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

I/O Data Sample Rx Indicator

We’ve covered all the basic API frame types used to issue local commands, transmit information, receive information, and check on the status of our commands and transmissions. Since you’ve made it this far, it should be pretty easy to understand the next API frame type. It contains the juiciest type of information—direct sensor data! This is how you will obtain real values from networks of remote sensors via the XBee’s direct input/output functionality. Your room temperature, soil moisture, monkey-trap status, or whatever, will arrive encased in this frame type.

The ZigBee I/O Sample Rx Indicator is really just an extension of the ZigBee Receive Packet discussed above. The main difference is that instead of the payload having an arbitrary or unconstrained format, it is organized in a highly structured way that lets us decode a set of digital and/or analog samples that were taken directly by the transmitting XBee. It’s important to note that I/O samples can’t be received in transparent/command mode at all. Using API mode is essential to receiving XBee direct I/O information. It’s one of the most important reasons for us to cover the API in this book.

All I/O samples are received inside what otherwise would appear to be a simple ZigBee Receive Packet. The first clue that it’s any different is its frame type of 0x92, which indicates that we’ll be getting an I/O data sample in the payload. After that, everything is the same up until the first payload ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required