Thursday, February 6, 2014

Building a Wireless Temperature Sensor Network Part 1

In this ForceTronics' inaugural project we will be building a wireless temperature sensor network that will include features such as battery powered sensors and the ability to access the temperature data over the internet via a computer or an iOS device such as an iPhone.

The two main building blocks we will be using for this project are an Arduino Board (first the Uno and then later the Yun to add internet capability) and XBee Wireless RF Modules. Now it is assumed that the reader has a basic understanding what Arduino is and some basic experience with the Arduino Uno board, if you do not have Arduino experience don't fret just go to to get started and come back here when you are ready. As for XBee, no experience is necessary we will go over the basics of using XBee here for this project.

Building a wireless temperature sensor network is no easy task so we will break this project up into parts and each part will be covered in a separate post. The project will be broken up into 6 parts, they are as follows:
  1. Introduction, getting started with XBee, and using XBee with Arduino (This post is part 1)
  2. Gathering data from multiple sensors
  3. Design options for powering your sensor network
  4. Design options for powering your sensor network continued 
  5. Monitoring your sensor network over the internet and logging temperature data
  6. Connecting to your sensor network with your iOS device
The focus of the rest of this post will be to learn the basics of XBee and how to use it with Arduino. In an attempt not to reinvent the wheel, we will refer to some fantastic XBee video tutorials created by "tunnelsup." The "XBee Basics" video tutorials is a series made up of 5 video, but you do not need to do all of the videos to complete this project. I am recommended that you actually get the parts and complete Lessons 1 and 4. For lessons 2 and 3 I recommend you watch them and follow along, but you do not need to actually get all the parts and do them (unless you want to). You will not need to do lesson 5 for this project, but if you want to feel free it can only help. Each video provides a parts list of what is needed to complete the tutorial, but if you want to buy in bulk to get you through part 1 and 2 of this project see the parts list at the end of this post.

XBee Basics - Lesson 1 - General Information and Initial Setup

XBee Basics - Lesson 2 - Simple Chat Program Between Two XBees

Hardware you will need for part 1 and 2 of the wireless temperature sensor network project is listed below. Two places where you can buy all this hardware is and
  • An Arduino Uno or similar Arduino board. When we add internet connectivity in part 4 to our sensor network we will switch to the Arduino Yun. 
  • Three XBee Modules, ZB Series 2, 2mW with Wire Antenna.
  • Either three XBee Explorers USB from SparkFun or three XBee Adapter Kits from Adafruit (used in video tutorial) for programming and connecting to our XBee modules. If you want to save some money you could just buy two XBee Explorer boards or Xvee Adapter boards, but you will need to buy parts to get your XBee board to plug into a standard breadboard.
  • At least two cables to connect your XBee Explorer boards or XBee Adapter boards to a computer. See the product details for which type cable you need with your board.
  • Three mini breadboards.
  • Three TMP36 or MCP9700 temperature sensors.
  • A power supply that is capable of outputting 3.3 V for powering two of the XBee modules. If you are using the Adafruit Xbee Adapter Kits your power supply can output anywhere between 3.3 V and 5 V since they have an onboard regulator. The third XBee module will be powered by the Arduino board. 
  • Wiring, wire strippers, and a soldering iron
That is it for part 1 of building a wireless temperature sensor network. If you have any questions on what was covered here feel free to asked them in the comments section below or email me at Stay tuned for part 2!


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  2. Thank you for the great article. Could I use a digital sensor like DHT22 instead of the analog ones?

    1. You could definitely use the DHT22 with an Arduino and configure an Arduino digital pin to read the digital communication of the DHT22 that gives you the temperature value. I am not sure if the DHT22 will work with just an XBee module (no Arduino). The XBee does have digital pins but they have fairly simple functionality. You would have to take a close look at the XBee manual and the DHT22 communication protocol to see if direct communication with the XBee is possible. You could always use the DHT22 with an Arduino and an XBee module, just not sure if you can use the DHT22 with just an XBee. Hope this answers your question.