i need a programme for interfacing of alcohol sensor with 8051 microcontroller

interfacing of mq 3 alcohol sensor with 8051

This article is about a breathalyzer circuit using 8051 microcontroller which outputs the blood alcohol content (BAC) from the breath. The BAC is displayed in percentage on a 3 digit seven segment display. The microcontroller used if AT89S51 which belongs to the 8051 family and the alcohol sensor is MQ135 gas sensor from Futurelec.

MQ135 gas sensor.

MQ135 is a stable and sensitive gas sensor which can detect ammonia, carbon dioxide, alcohol, smoke, nitrogen dioxide etc. The sensor consists of a tin dioxide sensitive layer inside aluminium oxide micro tubes, measuring electrode and a heating element inside a tubular aluminium casing. The front end of the sensor is covered using a stainless steel net and the rear side holds the connection terminals.

The ethyl alcohol present in the breath is oxidized into acetic acid while passing over the heating element. This ethyl alcohol falls on the tin dioxide sensing layer and as a result its resistance decreases. This resistance variation is converted into a suitable voltage variation using an external load resistor.

Alcohol detector with vehicle controlling pcb design and assembly language program

Analog MQ-3 Alcohol Sensor Interface with AVR ATmega16 Micro-controller and LED display. Here, we will interface an MQ-3 analog alcohol sensor with ATmega16 micro-controller and we will show the value of the MQ-3 analog alcohol sensor in the 1X8 LED array.

Since the output of the MQ-3 Alcohol analog sensor is analog in nature and these analog signals can not be processed directly by the ATmega16 micro-controller. Thus, in the first place this signal needs to be converted to digital value to be processed by the micro-controller. The conversion can be done with the aid of the ADC of the ATRmega16 micro-controller of the AVR. After converting the analog to digital signal, the micro-controller will display the digital value of the Analog MQ-3 Alcohol Sensor in the 1 × 8 LED array. But the LED array can display only 8 bits at a time. Therefore, the 1 × 8 LED array will first display the lower 8 bits and then the upper 2 bits of the 10-bit digital output with a delay of 500 ms.

Now, we are going to place the cotton submerged in Alcohol / Spirit near the Analog MQ-3 Alcohol Sensor and we will see the changes in the output of the Analog MQ-3 Alcohol Sensor in the LED array.