KIT-13197

Page 1 of 13   XBee Shield Hookup Guide CONTRIBUTORS: JIMB0 Introduction The XBee Shield gives your Arduino a seamless interface to XBee – one of the most popular wireless platforms around. With XBee, instead of being tied down by a serial cable – inches away from a paired device – your Arduino can pass data over the air to another device hundreds of feet away. Part of what makes XBee so popular is its simplicity. XBees are controlled over a serial interface – in the most basic operation they can be used as a wireless serial cable. Setting up XBee networks and addresses is also simplified with Digi’s free software – XCTU – which we explain in a separate tutorial. Covered In This Tutorial The goal of this tutorial is to set up wireless XBee communication between a computer and an Arduino/XBee Shield combo. Then, using a terminal program, we can remotely send data to an Arduino, or read data off of it. Page 2 of 13 We’ll begin by examining the schematics and hardware of the XBee Shield, then move on to example code. First we’ll set up a test program to make sure our XBees are communicating with each other. Then we’ll move on to the remote control Arduino sketch. Materials Required • 1x XBee Shield – The star of this tutorial. ◦ You’ll also need headers to install into your shield. We recommend stackable headers. • 1x Arduino – The XBee Shield should work with any Arduinocompatible board – Uno, RedBoard, Mega, you name it. • 2x XBees – XBees exist in a variety of series, frequencies, and ranges. If you’re just getting started with XBee, we highly recommend going with Series 1 models – either with a trace antenna, wire antenna or u.fl connector. ◦ For more help picking an XBee, check out our XBee Buying Guide. • 1x Explorer – The Explorer board allows you to connect an XBee to your computer. You can use either the Explorer USB, Explorer USB Dongle, or Explorer Serial. ◦ Depending on which explorer you have, you may also need a matching mini-B USB or serial cables. • At least one computer with X-CTU installed. ◦ The latest version of X-CTU is available for both Mac and Windows! • Soldering tools to install headers into your shield. The most basic of irons and solder should do. Suggested Reading Before reading through this tutorial, we highly recommend checking out the Exploring XBees and XCTU tutorial. That tutorial will introduce you to XCTU and explain how to configure XBee networks and addresses. In addition to that tutorial, we also recommend checking these guides out: • Serial Communication – Serial communication is critical to controlling and managing XBees. • Arduino Shields – The basics of Arduino Shields, including how to assemble a shield. • XBee Buying Guide – We highly recommend Series 1 XBee’s, if this is your first time playing with them. If you’re curious about other XBee classes, check out this guide! Hardware Overview Here’s a quick overview of the most components of the XBee Shield: Page 3 of 13 Below we’ll go more in-depth on the most important components of the shield. UART/SoftwareSerial Switch One of the most important components on the XBee Shield is the DLINE/UART switch. This switch controls which Arduino pins interface with the XBee. The Arduino Uno has a single hardware UART, which is usually either used for programming (via the Arduino’s serial bootloader) or communication with the serial monitor. That serial port can only be used to communicate with one device at any time, lest you run into problems of bus contention. There’s also a chance that, during program upload, spurious – even harmful – data might be sent to any device attached to the Arduino’s hardware UART. So to avoid any problems that might arise from connecting the XBee to the Arduino’s hardware UART, we usually take advantage of the Software Serial library, connecting the XBee’s RX and TX pins to a pair of free digital pins on the Arduino. To select between software and hardware serial, the XBee Shield includes a small, surface-mount slide switch. This switch allows you to select between the hardware serial port (UART position) and a software serial port connected to pins 2 (Arduino-side RX) and 3 (Arduino-side TX). The switch configuration from the XBee Shield schematic. “D_TX” connects to Arduino pin 3, and “D_RX” connects to Arduino pin 2. For all of our example sketches we’ll assume the switch is in the DLINE position. At the very least, make sure the switch is in the “DLINE” position when uploading sketches. LED Indicators Page 4 of 13 There are 5 LEDs on the XBee Shield. Each of these LEDs connects to a pin on the XBee, which does most of the LED driving. Here’s a table explaining the operation of each LED: LED Label PWR LED XBee Pin Color Connection Red 3.3V DIO5 Green DOUT Red DIN Green RSSI Green Default Operation Notes Indicates power is present. Associated indicator -- blinks when the Associate/DIO5 XBee is associated with another XBee. Indicates wireless data is being DOUT received. Indicates wireless data is being DIN transmitted. Indicates relative signal strength (RSSI) PWM0/RSSI of last received transmission. These LEDs can be very useful for debugging. The DIO5/Associate indicator should blink when the XBee is paired with a compatible device. The RSSI LED is actually PWM’d so it will be brighter when the paired XBee is closer (sending a stronger signal). Assembly Tips Before you can use the XBee Shield with your Arduino, you’ll need to solder in some headers. Check out the assembly page of our Shield tutorial for all of the tips and tricks related to header installation. XBee Socket There is some white silkscreen on the Shield PCB to help orient your XBee as you’re plugging it in. Make sure to match up the XBee’s two diagonal edges with the two diagonal lines on the PCB. With everything installed, you’re ready for the next step! Time to code… Example: Communication Test Lets start simple. In this section we’ll upload a sketch which passes data between your serial monitor and the XBee. This sketch can be use to create a “portal of communication” between your Arduino’s serial monitor, and another XBee (connected to a computer via a USB Explorer). Page 5 of 13 Double-Check Your XBee Network Before continuing with this example, you’ll need to make sure your XBee’s are configured correctly – they need to be on the same network and have compatible destination and MY addresses. By default, XBees will all be compatibly configured, but we recommend setting up unique network ID’s and addresses. Check out the Configuring Networks page of our Exploring XBee’s and XCTU tutorial for help with that. This example assumes you have XCTU installed and two compatiblyconfigured XBees – one connected to your computer via a USB Explorer (or Dongle, or Serial Explorer) and another plugged into the Shield/Arduino. The Arduino Sketch Here’s the sketch we’ll use. It makes use of the SoftwareSerial library, which is included with all of the recent Arduino releases. Before uploading this sketch make sure the switch on the Shield is in the “DLINE” position! Page 6 of 13 /************************************************************* ****  XBee_Serial_Passthrough.ino  Set up a software serial port to pass data between an XBee Shi eld  and the serial monitor.  Hardware Hookup:    The XBee Shield makes all of the connections you'll need    between Arduino and XBee. If you have the shield make    sure the SWITCH IS IN THE "DLINE" POSITION. That will connec t    the XBee's DOUT and DIN pins to Arduino pins 2 and 3.  ************************************************************** ***/ // We'll use SoftwareSerial to communicate with the XBee: #include  // XBee's DOUT (TX) is connected to pin 2 (Arduino's Software  RX) // XBee's DIN (RX) is connected to pin 3 (Arduino's Software T X) SoftwareSerial XBee(2, 3); // RX, TX void setup() {  // Set up both ports at 9600 baud. This value is most import ant // for the XBee. Make sure the baud rate matches the config // setting of your XBee.   XBee.begin(9600);   Serial.begin(9600); }  void loop() {  if (Serial.available())   { // If data comes in from serial monitor, send it out to XB ee     XBee.write(Serial.read());   }  if (XBee.available())   { // If data comes in from XBee, send it out to serial monit or     Serial.write(XBee.read());   }  }  After you’ve uploaded the code, follow this series of steps to verify that everything is working: 1. Open the Arduino’s Serial Monitor. Make sure the baud rate is set to 9600. 2. Switch to XCTU and click over to console mode. 3. Type something in the console view, it should show up on the Serial Monitor. 4. Type something into the Serial Monitor (and press “Send”), it should show up in the console view. 5. Yay! Page 7 of 13 You can use this setup to create a chat system. If you have another computer nearby, try to see how far your XBees can be from each other while still reliably communicating. If your XBee’s aren’t communicating with each other, try getting them closer together (if they were far apart to begin with). Otherwise, check out our troubleshooting section of the Exploring XBee tutorial. Example: Remote Control Arduino Setting up a chat system is fun, but where XBees and the XBee Shield really shine is in passing data to and from an Arduino, so you can remotely control it or receive data from it. In this example, we’ll create a simple serial interface, which can be used to set and read analog and digital pins. Example Sketch Here’s the sketch. Copy and paste from below, or click here to download it. Page 8 of 13 /************************************************************* ****  XBee_Remote_Control.ino  Write your Arduino's pins (analog or digital) or read from tho se  pins (analog or digital) using a remote XBee.  Jim Lindblom @ SparkFun Electronics  Original Creation Date: May 7, 2014  This sketch requires an XBee, XBee Shield and another XBee tie d to  your computer (via a USB Explorer). You can use XCTU's consol e, or  another serial terminal program (even the serial monitor!), t o send  commands to the Arduino.   Example usage (send these commands from your computer termina l):      w#nnn ­ analog WRITE pin # to nnn        e.g. w6088 ­ write pin 6 to 88      d#v   ­ digital WRITE pin # to v        e.g. ddh ­ Write pin 13 High      r#    ­ digital READ digital pin #        e.g. r3 ­ Digital read pin 3      a#    ­ analog READ analog pin #        e.g. a0 ­ Read analog pin 0      ­ Use hex values for pins 10­13      ­ Upper or lowercase works      ­ Use 0, l, or L to write LOW      ­ Use 1, h, or H to write HIGH  Hardware Hookup:    The Arduino shield makes all of the connections you'll need    between Arduino and XBee. Make sure the SWITCH IS IN THE     "DLINE" POSITION.  Development environment specifics:      IDE: Arduino 1.0.5      Hardware Platform: SparkFun RedBoard      XBee Shield & XBee Series 1 1mW (w/ whip antenna)          XBee USB Explorer connected to computer with another            XBee Series 1 1mW connected to that.  This code is beerware; if you see me (or any other SparkFun   employee) at the local, and you've found our code helpful, ple ase   buy us a round!  Distributed as­is; no warranty is given.  ************************************************************** ***/ // SoftwareSerial is used to communicate with the XBee #include  SoftwareSerial XBee(2, 3); // Arduino RX, TX (XBee Dout, Din) void setup() {  // Initialize XBee Software Serial port. Make sure the baud // rate matches your XBee setting (9600 is default).   XBee.begin(9600);  printMenu(); // Print a helpful menu: Page 9 of 13 }  void loop() {  // In loop() we continously check to see if a command has be en //  received. if (XBee.available())   {  char c = XBee.read(); switch (c)     {  case 'w':      // If received 'w' case 'W':      // or 'W' writeAPin(); // Write analog pin break; case 'd':      // If received 'd' case 'D':      // or 'D' writeDPin(); // Write digital pin break; case 'r':      // If received 'r' case 'R':      // or 'R' readDPin();  // Read digital pin break; case 'a':      // If received 'a' case 'A':      // or 'A' readAPin();  // Read analog pin break;     }    }  }  // Write Digital Pin // Send a 'd' or 'D' to enter. // Then send a pin # //   Use numbers for 0­9, and hex (a, b, c, or d) for 10­13 // Then send a value for high or low //   Use h, H, or 1 for HIGH. Use l, L, or 0 for LOW void writeDPin() {  while (XBee.available() < 2)     ; // Wait for pin and value to become available char pin = XBee.read(); char hl = ASCIItoHL(XBee.read()); // Print a message to let the control know of our intention s:   XBee.print("Setting pin ");   XBee.print(pin);   XBee.print(" to ");   XBee.println(hl ? "HIGH" : "LOW");   pin = ASCIItoInt(pin); // Convert ASCCI to a 0­13 value pinMode(pin, OUTPUT); // Set pin as an OUTPUT digitalWrite(pin, hl); // Write pin accordingly }  // Write Analog Pin // Send 'w' or 'W' to enter // Then send a pin # //   Use numbers for 0­9, and hex (a, b, c, or d) for 10­13 //   (it's not smart enough (but it could be) to error on //    a non­analog output pin) // Then send a 3­digit analog value. Page 10 of 13 //   Must send all 3 digits, so use leading zeros if necessar y. void writeAPin() {  while (XBee.available() < 4)     ; // Wait for pin and three value numbers to be received char pin = XBee.read(); // Read in the pin number int value = ASCIItoInt(XBee.read()) * 100; // Convert next t hree   value += ASCIItoInt(XBee.read()) * 10;     // chars to a 3­d igit   value += ASCIItoInt(XBee.read());          // number.   value = constrain(value, 0, 255); // Constrain that number. // Print a message to let the control know of our intention s:   XBee.print("Setting pin ");   XBee.print(pin);   XBee.print(" to ");   XBee.println(value);   pin = ASCIItoInt(pin); // Convert ASCCI to a 0­13 value pinMode(pin, OUTPUT); // Set pin as an OUTPUT analogWrite(pin, value); // Write pin accordingly }  // Read Digital Pin // Send 'r' or 'R' to enter // Then send a digital pin # to be read // The Arduino will print the digital reading of the pin to XB ee. void readDPin() {  while (XBee.available() < 1)     ; // Wait for pin # to be available. char pin = XBee.read(); // Read in the pin value // Print beggining of message   XBee.print("Pin ");   XBee.print(pin);   pin = ASCIItoInt(pin); // Convert pin to 0­13 value pinMode(pin, INPUT); // Set as input // Print the rest of the message:   XBee.print(" = ");    XBee.println(digitalRead(pin)); }  // Read Analog Pin // Send 'a' or 'A' to enter // Then send an analog pin # to be read. // The Arduino will print the analog reading of the pin to XBe e. void readAPin() {  while (XBee.available() < 1)     ; // Wait for pin # to be available char pin = XBee.read(); // read in the pin value // Print beginning of message   XBee.print("Pin A");   XBee.print(pin);   pin = ASCIItoInt(pin); // Convert pin to 0­6 value // Printthe rest of the message: Page 11 of 13   XBee.print(" = ");   XBee.println(analogRead(pin)); }  // ASCIItoHL // Helper function to turn an ASCII value into either HIGH or  LOW int ASCIItoHL(char c) {  // If received 0, byte value 0, L, or l: return LOW // If received 1, byte value 1, H, or h: return HIGH if ((c == '0') || (c == 0) || (c == 'L') || (c == 'l')) return LOW; else if ((c == '1') || (c == 1) || (c == 'H') || (c == 'h')) return HIGH; else return ­1; }  // ASCIItoInt // Helper function to turn an ASCII hex value into a 0­15 byt e val int ASCIItoInt(char c) {  if ((c >= '0') && (c = 'A') && (c = 'a') && (c