Specifications

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for the user. A smart HVAC control system would have a diagnostic element that
would present the user with the expected problem and a solution for the problem.
Remote control of the HVAC system is another motivation behind a smart control
system. Since such a large percentage of the population have internet ready
mobile devices in their pocket whenever they are on the go, there is a need to
allow these people to control their HVAC systems while away from the building it
is installed in. The LCD interface should connect to the internet and allow the
user to connect via mobile device to change settings and view current conditions
wherever internet is available.
1.3 Objective
The system is expected to sense data, wirelessly report it to a main control unit
where that data is analyzed, a decision is made, and the proper components are
activated. The system is designed to be installed relatively easily and therefore
the components must communicate wirelessly so that processes such as running
new wiring for the system can be avoided. There are several elements that must
be met in order to satisfy our sponsors.
1. The system must accurately read temperature and relative humidity
outside the building.
2. The system must accurately read the temperature and relative humidity
inside the building.
3. The system must wirelessly transmit data to a main control unit.
4. The main control unit must take the temperature and relative humidity as
inputs along with the user determined settings and make a decision of
how to cool, heat, raise or lower the humidity in the building in the most
energy and cost efficient manner.
5. The main control unit must control relays that will provide the necessary
components with the power they need.
6. The main control unit must have an LCD touch screen interface that must
be large enough for the user to easily see and operate.
7. The main control unit must communicate with the internet so that the user
can manipulate it from a remote location via mobile device.
1.3.1 Remote Sensing Unit
A remote sensing unit is to be set up outside the building. This unit must
accurately measure the temperature and relative humidity outside the building.
The values of temperature and relative humidity must be passed from a sensor to
a microcontroller located on the same printed circuit board as the sensor. The
microcontroller must then pass the values to a wireless chip that will wirelessly
report these values to the main control unit. The remote sensing unit is designed
to operate outdoors and therefore must be able to withstand harsh elements
such as wind, rain, extreme heat and extreme cold. The point of implementing
an outdoor sensor is so the system can check the exterior air conditions and