Vehicle Locking System Using an Electronic Breathalyzer and Notification by Mobile Communication

This paper presents the implementation of a prototype to lock/unlock the vehicle ignition system. It involves the adaptation of an opto-isolated relay, which has been equipped with a wireless interface of the MQTT protocol. The relay activation is controlled by an embedded board Raspberry Pi 3; it acts as the main unit of the proposed system. The executed control actions are given depending on the information received by radiofrequency from an implemented electronic breathalyzer. This device evaluates the alcohol level and humidity in the driver’s breath using the MQ-3 and DHT11 sensors. In addition, a mobile communication platform compatible with Android smartphones is provided to inform the enabling/disabling of the vehicle’s ignition system, its geographical location by GPS coordinates and a front facial photograph of the driver. All these features are incorporated by a wireless local network (WiFi) for the elements that make up the prototype. This work also presents the transmission of information to mobile terminals compatible with the Telegram instant messaging system through the UMTS network. In order to validate this proposal, the corresponding tests are carried out and their comparison with a commercial device.