Xbee wireless humidity measurement



Arduino Based X-bee communication

with Humidity Sensor


Submitted by:       Submitted to:




 We are thankful to Mrs. Manu Bharti for their Guidance to select this project. We are very thankful to BCET college. This project will help us a lot in practical training. It’s the time to implement theoretical knowledge to practical implementation.

Introduction and Working:

Smart Ordering Sysem is our MAJOR final Year Project. We planned lot of project but finally we decided to make this project.

In this project LCD will show few items.  Project will be based on ZIG BEE and Arduino. In this project we use Arduino microcontroller as a main processor.. This controller is basically a  40 pin ic. In this project we use two sensor also.ROM of Arduino is 8k and ram is 256 byte. We are using 16*2 lcd in this project. Lcd is connected to port 0 which will display the no. On receiver side RF module will give signal to microcontroller. Microcontroller is decision maker here and informer to person on duty.It will give data to LCD , buzzer and LED’s. we will also use four LEDs for immediate action.

We will use Humidity sensor which will give analog data to Arduino module and arduino will transmitt signal using x- bee module

Pin no 40 is connected to the positive supply. In this project we provide a 5 volt dc power supply. This power supply is truly regulated power supply. Pin no 20 is connected to the negative supply. Here we supply a negative voltage on this pin. Crystal is connected to the pin no 18 and 19 of the microcontroller. Crystal provide a clock signal to run the vehicle and process all the internal requirement of the  circuit. We use two sensor and these two sensor are connected to the p3.4 and p3.5 of the microcontroller.For the regulated power supply we use ic 7805 as a regulator to provide a fix 5 volt power supply.

To Assemble the remote weather station you will go through the following step, and will elaborate on each below:

  1. Connect all the sensors to the Stalker/Arduino board
  2. Make minor modification to the Stalker
  3. Configure the XBee modules
  4. Load program onto the Stalker
  5. Run program on the PC

Connecting the sensors:
DHT22 connected to digital pin 2.

DHT22 Pin 1 to 3.3 Volt of Arduino
DHT22 Pin 4 to GND of Arduino
DHT22 Pin 2 to digital pin 2 of Arduino
10KOhm resistor between pin 1 (Vcc) to pin 2 (data) of the sensor
DHT22 Pin 3 is left not connected.
Consider using small bread-board for this small circuit

Console for debugging (optional) on digital pins 3 and 9 (9600 based console)

This is only useful if you want to see debug messages, change things in the SW etc.
For this to work you will need to connect the FTDI to the below pins or simply use
additional FTDI board (that’s what I did). If you only use one board then you will need
to connect it to the programming side, load the program then connect to the console pins to see the output, which is pretty tedious if you ask me.
To connect console only, here are the connections required:
GND from the FTDI to Arduino GND
Rx from the FTDI to digital pin 9 of the Arduino
Tx from the FTDI to digital pin 3 of the Arduino

BMP085 is connected to the I2C interface (analog pins 4 and 5 of the Arduino).

Vcc from sensor breakout board to 3.3V of Arduino
Gnd from sensor breakout board to GND of Arduino
SDA from sensor breakout board to Aruino analog pin 4
SCL from sensor breakout board to Arduino analog pin 5
If you are using small bread-board for the DHT22 sensor, you can probably include this sensor on it too.

Configuring the XBee modules
There is quite a bit of information and in-depth on the XBee modules on the net. I will not go into all the details here. Few notes though: The XBee modules have API mode and Command mode firmwares. I use the library that requires the API mode. Also, with Series 2 of XBee, there is a role for each module, so we need one coordinator that is connected to the PC and one endpoint which is the module installed on the remote weather station. Also there is some addressing information that needs to be identical between units, and I chose this address code to be 2266 (my birthday if anyone is curious). Obviously you can choose something different. On the coordinator side (PC) the AO needs to be 0. On the weather station side the AO should be 2 (but in any case I ignore the return codes, so it will work anyway).

  1. Install the X-CTU utility
  2. Optionally do firmware upgrade to the XBee Modules (please note you need the API mode firmware)
  3. Configure one unit to be coordinator and another to be endpoint
  4. Configuration for both coordinator and endpoint (the sensor) is included in the ZIP file for this instructable
  5. Write down the Coordinator XBee address (Nodes Addressing/SH andAddressing/SL).
  6. Place the XBee module configured as endpoint into the Stalker socket
  7. Place the XBee module configured as coordinator into the XBeeExplorer and connect it to the PC

We transmitter whole project in few steps:

RF transmitter

  • RF module
  • Encoder circuit

RF receiver

  • Rf receiver
  • Decoder
  • Microcontroller circuit
  • Visual indication- LCD and LEDs
  • Audio alert- buzzer


  • Low cost
  • Reliable
  • Portable
  • Flexible 
  • Easy to use
  • Protection
  • Communication


  • Wireless system
  • LCD display
  • X bee

Hardware required-

8051 programmer universal kit

CRO 20 Mhz

Digital multimeter

Software required:

Keil software- Microvision 2

ORCAD for PCB design 10.5

Proteus for simulation 7.4 version


X Bee  

Block Diagram of receiver

 Component List  COST  
1Arduino UNO311600  
 HT12E 1 35  
 Push to On Sw312  
 Crystal 12MHz225  
18IC BASE35  
 IF set1201  
19IC 7805 Volt. Reg215  
22RELAY 9V325  
24CRYSTAL 3.579545220  
27PLY BOARD1100  
28TAPE ROLL110  
29Copper Clad Board1100  
 TOTAL COST  9000  







Leave a Reply

Your email address will not be published. Required fields are marked *