Testing and reasult

For testing prototype, shown in figure 1, I used 4 microphone sensor. 4 microphone sensor is synchronized. The base is 78cm x 68cm. Each microphone is setting on the corner of base.

Figure 1

Figure 2

As a result, it found the position so ugly. It should be modify later.

Transmitter Module

For more energy of sound, I choose the buzzer in working voltage 12V. And I connect a buzzer to an Arduino with button. When I press the button,  buzzer will operates with arduinio output pulse. That pulse will turn on the NPN transistor in order to turn on buzzer.

Figure 1 shows the circuit of NPN transistor connect to buzzer.

Figure1: PCB design

Figure2: arduino prototype

In test with prototype, it must connect arduino GND pin to power supply when using external power supply (12V).

Figure3: Final version

Furthermore, final version of transmitter module can be connected with 12V battery.

Using Mega2560 for more interrupts

Figure 1

At 23 March 2016, I used Arduino Uno to determine which one triggered first. In figure 1, it shows that available interrupt pins in different boards. By limitation in Uno,  it has only 2 interrupt pins, so I bought Arduino Mega which has 6 interrupt pins for read all of 4 analog input pins. 

Figure 2

Figure 3

As a result, shown in figure 3, it determines more accuracy in true order but not micro second.