The MQ3 alcohol sensor is one of the series of MQ gas sensors, which can detect and monitor the alcohol gas present in the atmosphere. It is capable of detecting 25-500ppm alcohol gas concentration in the air. This article gives a brief description of the pin configuration, specifications, and Arduino interfacing of the MQ3 alcohol sensor. The alternatives of MQ3 alcohol sensors are MQ138 (benzene, hydrogen, alcohol, propane, toluene, formaldehyde gas), MQ303A (ethanol, smoke, and alcohol), MQ2(methane, smoke, LPG, butane), MQ214 (methane), MQ5 (natural gas and LPG), and MQ306A (LPG and butane).