Object detector

An object detector capable of detecting an object through transmission and reception of sound waves, the object detector comprising:

• a wave transmitter to transmit a modulated wave in a predetermined frequency range to an object;
• a first wave receiver to receive sound waves and to generate a first wave reception signal indicative of reception of the sound waves;
• a second wave receiver to receive sound waves and to generate a second wave reception signal indicative of reception of the sound waves, the second wave receiver being located farther from the wave transmitter than the first wave receiver;
• an adder to generate a third wave reception signal by adding the first wave reception signal and the second wave reception signal;
• and
• a controller to detect the object based on the third wave reception signal by causing the wave transmitter to transmit the modulated wave;
• wherein
• with the first and second wave receivers being arranged in a predetermined layout, a fluctuation range of the third wave reception signal generated upon receipt of the modulated wave from the wave transmitter is not more than a fluctuation range of the first wave reception signal generated upon receipt of the modulated wave.