CSC400-Wireless Networking

Student: Vilma Reyes
Adviser: Dominique Thiebaut (Paul Voss also supervises a complementary Independent Study performed in parallel with this one.)

Background

Existing pH-monitoring devices have sounding alarms as the main alerting system in order to inform diabetic patients when their pH level is in a critical state. However, diabetic patients can enter a state of coma if their body pH goes out of the healthy range (7.35 - 7.45). Therefore, a sounding alarm could prove to be useless. Especially, for college students or other diabetic patients that may live alone.

Introduction

For the course of a semester, I plan on working with existing technology to learn how to send an SMS or any other wireless signal. The new knowledge that I gain from working with Arduinos and learning how to transmit data over a wireless network will allow me to figure out a way to improve my current design clinic project - designing a less-invasive pH monitoring device. At the end of the semester, I hope to be able to transmit data on a wireless network from an Arduino or a microcontroller.

Background/Research

• Log page
• Definitions:

• Arduino
• Microcontroller
• XBee wireless kit

• Possible programs:

• Python

• Sending data from the microcontroller to a pc

• Data

• Sending an e-mail

• Email

• Sending an SMS

• SMS

XBee Testing

See this page for a communication test of XBee modules with an Arduino and a Mac.

Final Testing

• Propeller Program

• Code Description

The following code, written for a P8x32A-M44 Parallax microcontroller, prints the string "Hello Word__" by communicating wirelessly between two Xbees. The code specifies which pins are being used on the microcontroller to transmit and receive information and establishes a Baude rate. The last portion of the code encodes the transmitting XBee to send a string and to add a delay in between each transmission. An image of the set up is included below.

• Code

NOTE: Must use Windows to run code with the propeller Spin tool

CON
  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000
  XB_Rx = 17 ' XBee DOUT                            ' Set pins and Baud rate for XBee comms
  XB_Tx = 16 ' XBee DIN
  XB_Baud = 19200

Var
  long stack[50]                                    ' stack space for second cog
  
OBJ

  XB : "FullDuplexSerial"
  
Pub Start
                                              
  XB.start(XB_Rx, XB_Tx, XB_Baud)                   ' Initialize comms for XBee


  repeat
    XB.str(string("Hello World__"))                 ' Accept data from PC and send to XBee  
    waitcnt(clkfreq/2 + cnt)                        ' Wait a moment  
                          

• Images

• Circuit Blog diagram

• Picture of the final circuit

• Serial Communication with a Mac

• Step-by-step set up
  • Set up for the Mac Terminal to communicate with the Xbee:
    • Plug in Xbee base into USB port
    • Open Terminal (search in Finder)
    • Type "Is /devitty.*" into the Terminal window
    • Terminal will display all devices that are plugged in for serial communication. Take note of the Xbee. It will look something like this: "/dev/tty.usbserial-########" with an alphanumeric number at the end.
    • In order to begin communication with the Xbee, run this command in Terminal: "screen /dev/tty.usbserial-1414###### 19200" *Note that 19200 is the baud rate and can be changed as needed.
    • A window will pop up. Now, you're all set for talking to Xbee!
    • To finish communicating, press "control-A" and then "control-\"