The design of a smart integrated chemical sensor system that will enhance sensor performance and compatibility to ad-hoc network architecture remains a challenge. This work involves the design of an interface chip for a Surface Acoustic Wave (SAW) based chemical sensor where the sensor reflects the RF input and introduces a time delay proportional to the concentration of the vapors absorbed by it. The interface chip detects the frequency shift as a function of the chemical species absorbed by the sensor and alerts the ad hoc network controller when a monitored parameter exceeds some threshold, based on local processing and measurements. System components are designed in RF environment to carry out the local processing and estimation of the chemical absorbed. Simulation results for individual circuit components as well as the complete chip outline the robust performance of the system that improve chemical target detection and reduce false alarms.