|Wireless SD Shield Front||Wireless SD Shield Back|
The Wireless SD shield allows an Arduino board to communicate wirelessly using a wireless module. It is based on the Xbee modules from Digi, but can use any module with the same footprint. The module can communicate up to 100 feet indoors or 300 feet outdoors (with line-of-sight). It can be used as a serial/usb replacement or you can put it into a command mode and configure it for a variety of broadcast and mesh networking options. The shields breaks out each of the Xbee's pins to a through-hole solder pad.
Included on board is a SD card slot. When using the SD Library to access the card, Pin 4 is CS and cannot be used otherwise. SPI also relies on pins 11, 12, and 13 for communication.
An on-board switch allows the wireless module to communicate with the USB-to-serial converter or with the microntroller.
EAGLE files: arduino_WirelessShield_SD_v3-reference-design.zip
The Wireless SD shield has an on-board switch labelled Serial Select. It determines how the Xbee's serial communication connects to the serial communication between the microcontroller (ATmega8 or ATmega168) and USB-to-serial chip on the Arduino board.
When in the Micro position, the DOUT pin of the wireless module is connected to the RX pin of the microcontroller; and DIN is connected to TX. The wireless module will then communicate with the microcontroller. Note that the RX and TX pins of the microcontroller are still connected to the TX and RX pins (respectively) of the USB-to-serial converter. Data sent from the microcontroller will be transmitted to the computer via USB as well as being sent wirelessly by the wireless module. The microcontroller will not be programmable via USB in this mode.
With the switch in the USB position, the DOUT pin the wireless module is connected to the RX pin of the USB-to-serial converter, and DIN on the wireless module is connected to the TX pin of the USB-to-serial converter. This means that the module can communicate directly with the computer. The microcontroller on the board will be bypassed. To use the shield in this mode, you must program the microcontroller with an empty sketch (shown below), or remove it from the board.
The Wireless SD shield can be used with different modules with the same footprint as the XBee modules. The instructions below are for the XBee 802.15.4 modules (sometimes called "Series 1" to distinguish them from the Series 2 modules, although "Series 1" doesn't appear in the official name or product description) and also for the XBee ZNet 2.5 or XBee ZB modules, both known as "Series 2" modules. All the modules, basically have the same type of configuration parameters, but differ by the function that they implement and the topologies of networks that they can create. Can communicate with each other only modules of the same family.
There are multiple parameters that need to be configured correctly for two modules to talk to each other (although with the default settings, all modules should be able to talk to each other). They need to be on the same network, as set by the ID parameter (see "Configuration" below for more details on the parameters). The modules need to be on the same channel, as set by the CH parameter. Finally, a module's destination address (DH and DL parameters) determine which modules on its network and channel will receive the data it transmits. This can happen in a few ways:
Again, this address matching will only happen between modules on the same network and channel. If two modules are on different networks or channels, they can't communicate regardless of their addresses.
For the "Series 2" modules you must chose which firmware put on the module to give it Coordinator, Router or End Device functionality. Series 2 use only serial low (
SL) and serial high (
SH) for addressing.
Here are some of the more useful parameters for configuring your Xbee module. For step-by-step instructions on reading and writing them using AT commands, see the:
Make sure to prepend
AT to the parameter name when sending a command to the module (e.g. to read the
ID parameter, you should send the command
|Command||Description||Valid Values||Default Value|
| ||The network ID of the XBee module.||0 - 0xFFFF||3332|
| ||The channel of the XBee module.||0x0B - 0x1A||0X0C|
| || The serial number of the XBee module (|| 0 - 0xFFFFFFFF |
|different for each module|
| ||The 16-bit address of the module.||0 - 0xFFFF||0|
| || The destination address for wireless communication (|| 0 - 0xFFFFFFFF |
| 0 (for both |
| ||The baud rate used for serial communication with the Arduino board or computer.|| 0 (1200 bps) |
1 (2400 bps)
2 (4800 bps)
3 (9600 bps)
4 (19200 bps)
5 (38400 bps)
6 (57600 bps)
7 (115200 bps)
|3 (9600 baud)|
Note: although the valid and default values in the table above are written with a prefix of "0x" (to indicate that they are hexadecimal numbers), the module will not include the "0x" when reporting the value of a parameter, and you should omit it when setting values.
Here are a couple more useful commands for configuring the XBee module (you'll need to prepend
AT to these too).
| || Restore factory default settings (note that like parameter changes, this is not permanent unless followed by the |
| ||Write newly configured parameter values to non-volatile (long-term) storage. Otherwise, they will only last until the module loses power.|
| || Exit command mode now. (If you don't send any commands to the module for a few seconds, command mode will timeout and exit even without a |