ESP32 Thermostat Control Bridge

Overview: I need someone to build and test two small ESP32-based units that wirelessly bridge a programmable thermostat to a ducted gas heater, eliminating the need for a long wire run between them. Update - moving this to the top Location: Melbourne-based strongly preferred so we can meet for handover and a quick walkthrough. Realistically, this is not a project that can be completed outside Australia. Thanks to all who applied from other countries, but given the hardware components, that's not going to work. Background: I have a Brivis Buffalo ducted gas heater and a Brivis 1F83C-11PRBR programmable thermostat (battery powered). Currently the thermostat connects to the heater via two wires (W and R, carrying 24VAC). I want to remove this wire run and replace it with a wireless link. How it works: - The thermostat closes the W/R circuit when calling for heat (24VAC signal) - A sender unit (ESP32 + optocoupler) reads this signal and transmits wirelessly - A receiver unit (ESP32 + relay) receives the signal and closes the W/R circuit at the heater end - The two ESP32s communicate via ESP-NOW (Espressif peer-to-peer protocol — no WiFi router or broker required) What I need built and tested: 1. Sender unit — ESP32 dev board with a PC817 optocoupler circuit to safely read the 24VAC W/R signal on a GPIO pin, transmitting state changes via ESP-NOW 2. Receiver unit — ESP32 dev board with a 5V relay module, receiving ESP-NOW packets and switching the relay to close/open the W/R circuit at the heater board 3. Both units to include a heartbeat/watchdog: sender transmits a keepalive every 60 seconds; receiver opens the relay (fail-safe off) if no packet received for 2 minutes 4. Code written in Arduino IDE (C++), well commented, provided to me as source files 5. Both units bench-tested together and confirmed working before delivery What I will handle separately: - A licensed electrician will install a USB power supply inside the heater cabinet for the receiver unit - The electrician will connect the relay output to the W/R terminals on the heater control board - The sender unit will be powered by a standard USB phone charger near the thermostat Parts: I am happy to purchase parts based on your recommendation, or you can supply them and invoice me. Expected parts: 2x ESP32 dev boards, PC817 optocoupler, 1kΩ and 10kΩ resistors, 5V single-channel relay module, breadboard or stripboard, short hookup wire. Skills required: - ESP32 / Arduino IDE development - ESP-NOW protocol - Basic analog electronics (optocoupler interfacing, 24VAC signal reading) - Relay module wiring - Ability to explain the finished build clearly to a non-expert Please include in your proposal: - Any similar projects you have built (HVAC control, relay switching, ESP-NOW or similar wireless links) - Your rough timeline - Whether you would supply parts or prefer I source them - Fixed price preferred