In this tutorial we will see how we can interface the MQ-3 Gas Sensor with Aries v2.0 Board.
The MQ3 alcohol sensor can detect alcohol concentrations ranging from 25 to 500 ppm. The sensor’s analog output voltage (at the A0 pin) varies in proportion to the alcohol concentration. The higher the concentration of alcohol in the air, the higher the output voltage; the lower the concentration, the lower the output voltage.
Technical Specifications
| Operating voltage | 5V |
| Heating consumption | <800mw |
| Sensing Resistance | 1 MΩ – 8 MΩ |
| Concentration Range | 25 – 500 ppm |
| Preheat Time | Over 24 hour |
Finding the threshold values
To estimate the level of alcohol intoxication, you need to record the values your sensor outputs when you blow on it before and after consuming alcohol.
Note:
If you are not legally permitted to consume alcoholic beverages, use an isopropyl alcohol bottle or any hand sanitizer bottle for your testing. Don’t get alcohol on the sensor. Simply squeeze the bottle to allow the alcohol vapours to enter the sensor and take your readings.
COMPONENTS NEEDED
- ARIES v2 Microcontroller
- An MQ-3 Alcohol sensor
- A breadboard
- Jumper wires
- 2.7K & 4.7K ohm resistors
Note: All of the following boards can be used for this project
| MQ-3 Gas Sensor | Aries Board |
| VCC | 5V |
| GND | GND |
| A0 | A0 using 2.7K & 4.7K Resistor |
Note: A voltage divider is required between MQ3 sensor output and Analog pin of Aries board, for accurate measurements. Connect a 2.7K resistor to A0 pin of MQ3 sensor. Connect one end of the 4.7K resistor in series to the 2.7K resistor, and the other end to the GND. Take the output from the junction of 2.7K and 4.7K resistors.
Now, for powering up the ARIES v2 board via the USB port of a Laptop/Desktop/PC and burning the code into the ARIES v2 board, we have to use a micro USB type B to USB type A cable. The cable should be connected to UART-0 port of the ARIES v2 board, and the Laptop/Desktop/PC should be preinstalled with Arduino IDE and VEGA ARIES boards of latest version.
Procedure:
Open Arduino IDE
Go to Tools -> Board -> VEGA Processor ARIES Boards -> Select ARIES v2
Go to Tools -> Programmer -> Select VEGA XMODEM
Connect the ARIES v2 board to PC
Go to Tools -> Port -> Select the appropriate port
Open File -> Examples -> Examples for ARIES v2 -> ADC -> Open MQ3_Gas Sensor example
Compile and Upload the code
Output:
As we know the MQ-3 Gas sensor can detect gases like Alcohol, Benzene (C6H6), CH4, LPG and other harmful gases and smoke , Similar to other MQ series gas sensor, this sensor also has a digital and analog output pin. We can set the threshold value according to the Sensor , by bringing the alcoholic material nearby to this sensor the level of these gases go beyond a threshold limit in the air and the digital pin goes high & we will get the output as “Alcohol Detected” with Red LED (built-in) ON , otherwise the output as “No Alcohol Detected” in serial monitor.
