• Status: Draft
• A two-device smart-light control system: a rechargeable, wall-mounted Decora-style paddle remote and an always-powered ESP32 gateway.
• The remote replaces the interaction of a light switch without connecting to household wiring. It allows the existing mains switch to remain on so basement receptacles continue powering dehumidifiers while Home Assistant controls Govee Matter bulbs.

• Indoor residential basement.
• Remote mounts to a wall using one or two removable adhesive strips and may also be used as a portable remote.
• First revision is a functional prototype intended to validate responsiveness, runtime, ergonomics, charging, and Home Assistant integration.

• Wake when the lower portion of a spring-return paddle is pressed.
• Recognize single, double, multiple, and long presses.
• Send the event with near-instant perceived response to an always-powered gateway over ESP-NOW.
• Have the gateway expose the event to Home Assistant for user-configurable actions.
• Measure and report remote battery level.
• Provide brief local status indication without materially reducing runtime.
• Recharge through USB-C.

• Full-size Decora-inspired single-bottom-press paddle.
• No connection to mains wiring.
• ESP32-family radio modules in both remote and gateway.
• ESP-NOW low-latency link between remote and gateway.
• Wi-Fi/Home Assistant connectivity at the powered gateway.
• Protected rechargeable single-cell LiPo battery.
• USB-C charging and programming/debug access.
• Battery voltage measurement and status LED.

Diagram

• Low-power ESP32 module with PCB antenna.
• Momentary paddle actuator or microswitch suitable for wake-from-deep-sleep.
• USB-C 5 V sink input with ESD protection and CC resistors.
• Single-cell LiPo charger and battery protection strategy.
• Low-quiescent-current 3.3 V regulation sized for ESP32 radio bursts.
• Battery monitor divider switched or high impedance to minimize sleep drain.
• Low-current status LED, active only briefly.
• BOOT/RESET and programming access.

• ESP32 module powered continuously from USB-C 5 V.
• ESP-NOW receiver and Wi-Fi/Home Assistant bridge.
• 3.3 V regulator sized for continuous Wi-Fi operation and peak radio current.
• Status indication and programming/debug access.

• Remote USB-C: 5 V charging and optional native USB programming if supported by the selected ESP32 variant.
• Remote paddle: momentary active-low wake input with hardware pull-up and debounce handled primarily in firmware.
• Remote battery monitor: ADC-capable GPIO, avoiding restricted or strapping pins.
• Remote status LED: GPIO-controlled, normally off.
• Radio link: ESP-NOW event packets with device ID, event type, sequence number, and battery data.
• Gateway USB-C: 5 V power and programming.
• Gateway network: 2.4 GHz Wi-Fi to Home Assistant/ESPHome.

• Minimum runtime: 6 months between charges.
• Design usage: 15 paddle interactions per day.
• Near-instant response takes priority over direct Wi-Fi from the sleeping remote; the remote therefore uses ESP-NOW to an always-on gateway.
• The remote should spend nearly all time in deep sleep, waking on paddle activity and periodic/press-triggered battery reporting.
• Target battery capacity range is initially 1000–2000 mAh, subject to measured sleep current and enclosure fit.

Diagram

• Detailed current modes and runtime calculation will be maintained in the Power Budget project file after component selection.
• The regulator and battery must tolerate ESP32 transmit bursts with adequate local bulk capacitance.

Diagram

• Prototype-oriented custom PCBs using commonly available components and standard two-layer fabrication where practical.
• Use pre-certified ESP32 modules rather than bare RF chips.
• Prefer assembly-friendly packages; avoid unnecessarily fine-pitch parts.
• Provide test access for 5 V, battery, 3.3 V, ground, reset, boot, and serial/native USB programming.
• Remote and gateway are separate physical boards; this project initially documents both schematic blocks before board separation/layout decisions.

• Remote must wake from deep sleep on paddle input.
• Press classification must support single, double, multi-press, and long press.
• ESP-NOW packets should be acknowledged/retried briefly while maintaining responsiveness and low energy use.
• Battery voltage should be sampled after wake and reported at a rate that avoids unnecessary power use.
• Gateway remains powered, receives ESP-NOW packets, and publishes events and battery state to Home Assistant.
• Include stable device identity, duplicate-packet rejection, pairing/configuration path, and recovery after power loss.
• Firmware updates occur over USB initially; gateway OTA may be added later.

• Full-size Decora-inspired front proportions and paddle feel.
• Self-contained enclosure with flat rear surface for adhesive strips.
• Side- or bottom-accessible USB-C port while mounted.
• Sufficient internal volume for a 1000–2000 mAh pouch cell without compressing or bending it.
• ESP32 antenna located away from the LiPo, ground/copper, metal hardware, and wall-facing obstructions.
• Indoor environment; no weather sealing required for the first revision.

• Use a dedicated powered gateway instead of connecting the sleeping remote directly to Wi-Fi, prioritizing response time and battery life.
• Use ESP-NOW for the remote link and Home Assistant/ESPHome integration at the gateway.
• Use a spring-return lower paddle rather than a mechanically latching switch.
• Expose flexible press events rather than hard-coding only a light toggle.
• Use rechargeable USB-C power rather than replaceable cells.
• Both boards use ESP32-C3-MINI-1-N4 modules with native USB on GPIO18/GPIO19.
• Remote regulation uses a TPS63802 buck-boost at 3.3 V; gateway regulation uses an AP63203 fixed 3.3 V buck.
• Remote charging uses an MCP73831-2ACI/MC DFN charger programmed nominally for 500 mA. It is a simple charger without a system power-path; the remote load is connected at the battery node.
• REM_* and GW_* power and ground nets are electrically separate in the schematic.

• Home Assistant and 2.4 GHz Wi-Fi coverage are available near the gateway.
• The gateway can be placed within reliable ESP-NOW range of the basement remote.
• The Govee Matter bulbs are already commissioned and controllable from Home Assistant.
• The first prototype may use custom ESP32/Arduino firmware on the remote if ESPHome cannot provide the required low-power ESP-NOW behavior; the gateway remains the ESPHome/Home Assistant integration point.
• Enclosure and paddle mechanics will be designed after PCB architecture and dimensions are validated.

• Typical press-to-Home-Assistant event latency feels near-instant, with a target below 300 ms under normal RF conditions.
• All supported press patterns are distinguishable and reliably delivered.
• Calculated runtime exceeds 6 months at 15 interactions/day with at least 20% engineering margin, then is confirmed by measured prototype sleep and event energy.
• Battery level appears in Home Assistant and low battery is locally indicated without a continuously illuminated LED.
• Remote charges safely from a standard USB-C 5 V supply.
• No household electrical wiring enters either device.

• Initial specification created from the requirements conversation.
• Architecture changed from direct ESPHome Wi-Fi wake-up to an ESP-NOW remote plus powered gateway to meet latency and runtime goals.
• Schematic electrically completed with separate remote and gateway domains, USB-C sink configuration, USB ESD, charging, regulators, boot/reset, debug headers, paddle wake, battery ADC, and LEDs.
• Charger package changed from SOT-23 to 2x3 mm DFN to improve thermal performance at the nominal 500 mA programmed current.