The SIMPATIC project (acronym for Intelligent System for the Private and Autonomous Surveillance based on Information and Communication Technologies, in Catalan) addresses the building of a monitoring system for people affected with Mild Cognitive Impairments (MCI). It consists of a mobile app running on the patient's smartphone and a server that analyses the device's location and raises alarms under certain conditions. This is a research project that comprises both technological and human challenges. Regarding the technological aspects, we have not merely built a testbed prototype: our technology has been tested in a real-life scenario. In this paper we address the implementation aspects and technological results of the pilot test conducted within the SIMPATIC project. We describe the architecture of the SIMPATIC system as well as its functionalities, but we focus on the implementation aspects that make our software a fully functional monitoring system based on smartphones and web technology.