PIC18F series microcontroller is used for the alcohol detection system. MQ series alcohol sensor interfacing with PIC18F4550 is done in this project. Then PIC microcontroller compares this value with the threshold limit this threshold limit can be 30% or 40%. The alcohol Detector mini project using PIC activates a buzzer and relay once this threshold limit is crossed. This Buzzer and Relay remain on as long as the alcohol percentage is more than the desired limit.
Whenever the alcohol level goes down then the buzzer is turned off. We have used a small buzzer in Bus and Truck Drunk Driver Alert Using the PIC project. But you can connect a large volume buzzer to the relay. The Buzzer in this project alerts the people that the person undergoing the alcohol test has consumed alcohol above the permissible limit.
Relay interfacing with the PIC18F microcontroller gives an additional feature to this project. We have not provided any output device for the relay along with this alcohol detector project using the PIC18F microcontroller. The output terminals of the relay are kept open. You can connect any DC device as well as an AC device at the output of this relay.
If any sensor gives output in millivolts then it requires an amplifier. An amplifier needs to be connected between the sensor and the analog input pin. The alcohol sensor gives 0 to 5 volts output. The output pin of the alcohol sensor is directly connected to the analog input pin of the PIC18F4550 microcontroller.
An important feature of the PIC18F microcontroller is that it has an internal analog-to-digital converter. There is no requirement for additional analog to digital converter IC to be connected externally. We can connect 8 sensors to the PIC18F4550 microcontroller. The internal ADC of the PIC18F microcontroller converts the analog input voltage of the sensor into the corresponding digital value. The main function of the PIC18F microcontroller in this project is to read the sensor output value and display the corresponding percentage of the sensor output on an LCD display, which is Liquid Crystal Display.
The power supply in this circuit:
A transformer is used in this circuit to generate the required power supply. But if you want to give the demo of this project in a car or motorcycle then you can remove the Transformer and connect the battery to a 12-volt battery to operate this project. Without any alteration in the circuit, the same project can be operated on AC or DC adapter or battery or a transformer.
Alcohol consumption at excess levels causes many problems such as drunk and drive cases. Accidents happen due to drunk and drive cases. Also, people misbehave due to the over-consumption of alcohol. So it’s really necessary to restrict drunken people at many places like Hospitals, Schools, and Colleges and importantly while driving. A PIC microcontroller-based alcohol detector can be used in such places for alcohol detection.