Specifications

5
determine whether or not the outdoor air is suitable to be brought into the
building.
Another objective of the remote sensing unit is to be easily installed. The remote
sensing unit is to be battery powered and report all information to the main
control unit wirelessly. By specifying these two characteristics the person
installing the unit has the difficulty of their job greatly decreased. If the remote
sensing unit required power to be delivered by wires or required wires to report
back the data it collects the installation person would be forced to run new wires
when retrofitting the system to an existing building. Running new wiring in an
existing building is an exhausting process that requires many hours and therefore
produces labor costs that would drive up the cost of the system. By making the
remote sensing unit battery powered and report data wirelessly the only
installation that is required is to pick an appropriate place on the exterior of the
building to mount the unit and then to mount the unit.
The ease of installation is one of the main objectives the group started with when
they first began the design of the remote sensing unit. The only downfall of
meeting the ease of installation objective is that all batteries eventually run out,
but with enough research about battery technology a battery can be chosen such
that battery replacement is minimized.
1.3.2 Main Control Unit
The main control unit is the most complex part of the system. It must accept
values that represent the outdoor temperature and relative humidity via a
wireless chip and pass these values to the main microprocessor. The main
microprocessor must store this information so that it can be used when making a
decision on whether the outdoor air is suitable to be exchanged with the current
air inside the building. The main control unit must also accept values from a local
sensor that will provide the temperature and relative humidity inside the building
(at the main control unit). This information must be stored so that it can be used
to tell the user the current inside temperature.
The main microprocessor must communicate with the LCD display. It must
recognize what buttons are being manipulated on the LCD and provide the
display unit the information it needs to update its output. The main control unit
must send and receive information to and from the web so that the user can
remotely check current settings and, if necessary, change them via mobile
device. The user should be able to manipulate both the desired temperature and
relative humidity for inside the building from the mobile device and have real time
temperature and relative humidity values from inside the building displayed on
the phone from anywhere they can access the internet.