Breathalyzer enabled ignition switch system

Breath alcohol detector or better known as breathalyzer plays a vital role in monitoring alcohol concentration in a person´s bloodstream. This project involves the design and development of breathalyzer device which controls ignition switch. The hardware modules include the PIC16F877A microcontroller, alcohol sensor, LCD panel and ignition switch circuitry. The software component includes the programming and source code which is implemented via the PIC microcontroller. Upon assembly, the system is able to detect alcohol concentration in a person´s breath sample and displays the detected amount in terms of BAC (Blood Alcohol Concentration) percentage on the LCD panel. Then, according to the amount, the system decides whether to enable or disable the ignition switch circuitry. The system can be very useful in enforcing the alcohol limit law.