I created these notes to help better understand the role of the components we are soldering on the MAKERbuino. They also contribute towards an understanding of the schematic. Please feel free to suggest changes.
Both the switches used in this project have three pins. Their operation is simple. If a switch is in the left position, the left pin is connected to the middle pin. If the switch is in the right position, the right pin is connected to the middle pin. This is achieved by the mechanical movement, of the connecting plate, caused by your finger.
Switch one connects the positive terminal of the battery to the V_BAT line on the circuit (seen in the schematic) and thereby completes the crucial power loop over the entire circuit, bringing it to life. When the switch is moved to the other position (off), the positive pole is connected to the other pin (3) of the switch which is not connected to anything. This means that the positive terminal of the battery is not connected to anything and therefore it is not being used.
Switch two performs a similar function for the speaker circuit. It completes the circuit for the speaker’s power when in one position and disconnects it in the other. When disconnected, the one side of the speaker is not connected to anything and therefore it cannot function. We will cover the rest of the speaker circuit later on.