How to coordinate message sending between xbees

During our project there were many times that one xbee just received part of the data that another xbee issued, leading the incomplete information communication. One effective way (at least works in our project) is to use delay to give the receiver/sender enough time to finish what they're trying to receive/send out. For example: In Picture sending, since there is a persistent data flow, which is long goes into the server, there is a large possibility that server will lose parts of them. So after each byte is sent, we will let the xbee to rest for 50 milliseconds and also the same amount of time for the server to get rest. In this way, we can coordinate the send and receive buffer of both ends and try to minimize the loss of data flow.

code in the sender (in arduino):

System Architecture and Project Functionality

On the embedded part, this project includes mainly three parts, and they are:

• Temperature Module
• monitor and adjust the home temperature
• Dimmer Module
• monitor and adjust the density of the lights
• Camera Module
• take pictures when motion is detected

The system architecture can be illustrated using this graph:

To gain a more detailed understanding, here are 10 main functionalities we aim to implement:

• User can see the recent temperature information
• User can see the most recent image which is detected
• The user should be able to put the system into a "stand-by" mode
• User can set a threshold of temperature to control the motor automatically
• User can get notification message on the phone 
• User can control the speed of motor to control temperature
• User can control the intensity of lights
• User can control the camera when to take a picture
• User can view graphs of history
• System can trigger the light when motion is detected