Boundary microphone

A boundary microphone comprising:

• a base;
• a microphone unit installed in the base and converting sound into an electrical signal;
• and
• a membrane pressure-sensitive switch turning on/off the output signal of the microphone unit,
• the membrane pressure-sensitive switch comprising:
• a circuit board provided with an electrode pattern detecting electrical conductivity;
• a membrane having a conductive surface;
• and
• a spacer interposed between the membrane and the circuit board,
• wherein the electrode pattern on a front surface of the circuit board is surrounded by a first ground pattern on the front surface of the circuit board,
• wherein the first ground pattern on the front surface is connected to a second ground pattern on a rear surface of the circuit board,
• wherein the spacer comprises a conductive material,
• wherein the conductive surface of the membrane, the first ground pattern on the front surface of the circuit board, and the spacer are electrically conducted, and
• wherein the electrode pattern is disposed between the conductive surface of the membrane and the second ground pattern on the rear surface of the circuit board.