Specifications

For the design section of the report we focused our research on the specific parts

we chose for the Efficient HVAC Control and Feedback System. Each part came

with either a datasheet or a user manual (sometimes both) provided by the

vendor selling the product. These datasheets and user manuals were essential

because they provided us with the detailed information that was necessary to

explain our subsystem in the design section of the research paper. Even though

these resources were used for the design portion of the paper, they provided us

with the most important research of the entire design process because of the

detail they provided us with pertaining to each individual part associated with the

system.

2.2 Main Microcontroller

The main and most integral component in our system is the main microcontroller.

The main microcontroller will be the most complex part of the system on both the

software and hardware side. The main microcontroller will be located in the main

control unit and is the central figure of the entire Efficient HVAC Control and

Feedback System. The main microcontroller is required to accept input from a

ZigBee wireless transceiver, a temperature and relative humidity sensor (also

located in the main control unit), the Internet via an 802.11b wireless internet

transceiver, and an LCD touch screen controller board. The main microcontroller

is also required to send output to the ZigBee wireless transceiver, the 802.11b

wireless transceiver, the LCD touch screen controller board, and to the 24V

control relays.

Internally, the microcontroller must be programmed to use these inputs to make

the correct decision about how it will choose to cool, heat, or ventilate the

building. The programming for this decision making process will be extensive so

there must be ample memory on the main microcontroller. Also, the main

microcontroller must be able to accept changes in the code so that it has extra

storage space to accept new code to be added in the future to incorporate

additional features that may be added to the Efficient HVAC Control and

Feedback System.

Because the main microcontroller is required to interface with so many other

components, it must have a sufficient amount of input and output pins and

designated ports such as I

C, SPI, and UART to be able to accommodate the

communication requirements of the other components. Before a microcontroller

could be chosen, the requirements and specs of our project had to be

considered, and a choice had to be made that provided a microcontroller that had

the necessary components to complete the project.

Since the main microcontroller is the main component of the entire system, it

must function perfectly for the system to work. The development of the main

microcontroller will be one of the most important aspects of the overall project

build and everyone in the group will be involved. We will be in close

communication with the sponsors prior to beginning the development of the main