Each submarine station runs on a PIC16f15356. Physical inputs consist of a reset button (SW1) and a button to fire torpedos (SW2). The system transmits a message by outputting an analog signal through the DAC, which is run through a unity gain buffer (MCP6294) and an RC filter. The resulting signal goes to an amplifier and speaker which output audio into a condenser microphone connected to a computer with Mumble voice chat. Push-to-talk is activated by a servo controlled by the PWM generator. We receive audio transmission with an electret microphone that is connected to another RC filter and then finally into the ADC. Finally a uart breakout is connected to the PIC so that we can send other commands through our computer as well as receive data from our PIC.
Circuit with the receive system (electret microphone and speakers) at the bottom
Receive system (left), Output speaker and the condenser microphone for transmitting messages (middle), and push-to-talk servo (right)