Fire detection and alarm sensor for avionics based on current loop circuit

A low cost and reliable fire detection and alarm sensor is proposed. It architecture uses the current loop circuit constructed in the form of nickel wire divided into several segments. The voltages are taken from the each segment and analyzed using a microprocessor. The growth of temperature associated with the occurrence of fire leads to an increase in the resistance of the corresponding wire segment and an increase in the amplitude of the signal taken from this section. Continuous monitoring of the voltage amplitudes taken from the wire segments makes it possible to determine the location of the fire that has arisen and to include an automatic fire extinguishing system. The procedure for voltage amplitude estimation is described and technique based on optimal design of experiments that allows one to simplify drastically the solution of obtained equations with microprocessor is given.