Specifications

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documented below to aid the design team design the rest of the breathalyzer
system if this time of sensor is chosen.
The fuel cell sensors are designed to have two platinum electrodes with a
porous acid-electrolyte material placed between the two. As the end user
exhales air and flows past one side of the fuel cell, the platinum oxidizes any
alcohol in the air to produce acetic acid, protons and electrons. The electrons will
flow through the wire from the platinum electrode. The wire is connected to an
electrical-current meter and to the platinum electrode on the other side. Protons
will move through the lower portion of the fuel cell and combine with oxygen and
the electrons on the other side to form water. As a result the more alcohol is
sampled and becomes oxidized, the greater the electrical current will be
outputted. It will then be measure and convert to BAC value by a selected
microcontroller in 2.1.
Figure 2.10-4 Reproduced with the permission of howstuffworks.com
Comparison: Fuel Cell Sensor & Semi Conductor Sensors
Pros
Cons
Fuel Cell
Higher accuracy
More Consistent
Results
Remain accurate
after a period of uses
Less warm up time
High Cost
Accessibility (Difficult
to obtain)
New Technology
(Very little
information
available)
Available in large