The system I choose to research is a simple “open-looped system” called the “Vehicle Frost Box”. This system is used to informing motor vehicle operators that likely conditions for icy roads are developing. Black ice cannot be seen and is a prime contributor to vehicle accidents during the winter months. If used, this simple system could actually save precious time, money and physical injury. For system development, the “Problem Statement” is; “Black ice cannot be seen on roads, causing safety hazards for drivers.” Next, the “Need Statement” is; “We need a way to determine when favorable weather conditions exist to form black ice on roads”. Last, the “Requirement Statement” consists of the following: the system must be cheep, reliable, and linear, with a low thermal mass allowing a quick response to variation in air temperature. There is a system already in use that is cheep. This system uses a liquid crystal strip attached to the drivers wing mirror. However, this attachment location is too high from the ground to properly determine road conditions. Additionally, some cars have heated mirrors, which would render this system useless.A silicone semiconductor junction, in the shape of a diode was chosen to build the design around. This option filled all the requirements listed in the “Requirement Statement”. Optional sensor devices were thermistors, thermometers, and thermocouples. These options were discarded because of high cost. The basic design of the frost box follows: Powered by vehicle ignition Uses a remote temperature sensor mounted close to the road surface Display is a single tri-color Light Emitting Diode (LED) Mounted on the drivers console Three modes indicating variations of external temperature * 4C = steady green light * 4C = steady red light * 0C...
