03 / ANATOMY OF A STATION
Behind the grille.
Proposed bench architecture. The drawing explains connections, not a verified installation pinout.
The original four-wire cable is intentionally excluded from this bench design until its route, gauge, condition and existing voltage are verified.
01 / THE RECOMMENDED FIRST BUILD
One Pi. One audio path. Two buttons.
Begin on the bench with a supported Pi, its recommended power supply, and a compatible USB audio interface with microphone input and audio output. Send line-level output to an amplifier matched to the speaker. Add the original controls only after isolating them from the old circuitry.
Use half-duplex intercom audio first: one direction at a time. Hands-free two-way audio requires acoustic echo cancellation and real-room testing.
02 / THE ORIGINAL CONTROLS
Keep the feel, inspect the circuit.
Test whether Talk and Monitor are momentary or latching contacts. Isolated contacts can feed GPIO inputs with appropriate pull-ups and debounce. GPIO signals are 3.3 V maximum, not legacy intercom voltage.
If the knob is a suitable isolated potentiometer, its wiper feeds an MCP3008 analogue input; the converter talks to the Pi over SPI. The Pi does not read an analogue knob directly. If unsuitable, retain the knob and replace the component behind it.
03 / POWER & THE OLD CABLE
Do not assume four wires mean Ethernet.
Use a proper local supply for the prototype. Long thin conductors can cause voltage drop. Any future low-voltage distribution needs measured cable data, current budgeting, protection and a suitable regulator at each station.
If new cable is practical, assess Cat6 plus standards-compliant PoE equipment for a reliable wired installation. The pool house still needs local power and tested Wi-Fi coverage.
04 / WHAT LIVES AT THE HUB
The house keeps the conversation.
The hub coordinates calling, message storage and integrations. Local calls should work without internet, while this proposed hub-based design depends on the hub. Each station should mute locally even if the hub fails.
“Room off” in this simulator is a software state. A real microphone privacy guarantee needs a hardware mute design. Cloud AI, presence and camera access require separate authenticated integrations.
