System Overview
Below is an overview of the electronic system and how the components interact to send and receive audio signals over the internet.
Electrical Schematic
The submarine is centralized around a PIC16F15356 microcontroller. It includes the following peripherals
- Audio amplifier and speaker which the PIC sends signals too using the internal DAC
- The PIC generates timer based interrupts at different rates and outputs a voltage from a sin lookup table to generate sin waves of different frequencies.
- Microphone that the PIC reads with the internal ADC to read the incoming voltages
- The ADC is read at a fixed rate (16.67 Khz) and stores the last 200 values which covers 12 ms. Then, the PIC looks through these values and finds the number of zero crossings to determine the number of periods over this fixed time and thus the frequency of the incoming wave.
- Three DIP switch inputs and one LED output
- Servo motor for actuating a push to talk key on a keyboard
- DC barrel jack for 5V power for the audio amplifier and servo