Radio Controller

A 433MHz RF light controller built with an ESP8266 (NodeMCU v2) and CC1101 transceiver, managed through ESPHome and integrated with Home Assistant. Controls bedroom and living room lights over ASK/OOK modulation using captured RC Switch codes, with Amazon Alexa voice control via emulated_hue. Also functions as a passive RF signal monitor, logging all received 433MHz transmissions for discovering nearby weather stations, door sensors, and other devices. Includes a parametric 3D printable case designed in OpenSCAD.

Hardware

NodeMCU v2 (ESP8266)	CC1101 RF Transceiver (433MHz)

Component	Details
MCU	NodeMCU ESP8266 v2 (nodemcuv2)
RF Transceiver	CC1101 with SMA antenna
Protocol	433.92 MHz ASK/OOK
Integration	Home Assistant via ESPHome native API
Voice control	Amazon Alexa via emulated_hue

Wiring (SPI)

CC1101 Pin	NodeMCU Pin	Function
SCK	D5 (GPIO14)	SPI Clock
MISO	D6 (GPIO12)	SPI Data Out
MOSI	D7 (GPIO13)	SPI Data In
CSN	D8 (GPIO15)	Chip Select
GDO0	D2 (GPIO4)	RX + TX (shared)
GDO2	D1 (GPIO5)	Connected, unused
VCC	3.3V	Power (NOT 5V!)
GND	GND	Ground

Note: GDO0 is shared for both receiving and transmitting via allow_other_uses: true. The CC1101 native component switches between RX/TX modes automatically using cc1101.begin_tx / cc1101.begin_rx triggers.

Features

• Bedroom lights (protocol 1) — Toggle, ON, OFF via HA buttons and Alexa voice commands
• Living room lights (protocol 3) — 8 buttons: toggle, on, off, timers (30s/30min/60min)
• RF monitoring — Counts received signals, logs all codes for device discovery
• Noise filtering — Protocol 2 code=0x0 spurious signals filtered out in lambda
• WiFi hardening — fast_connect, power_save_mode: none, max TX power for stable connection
• 3D printable case — Parametric OpenSCAD enclosure with SMA antenna pass-through

Architecture

┌──────────┐     SPI      ┌────────┐    433MHz    ┌──────────────┐
│ NodeMCU  │◄────────────►│ CC1101 │◄────────────►│ RF Lights    │
│ ESP8266  │              │  TX/RX │              │ (bedroom,    │
└────┬─────┘              └────────┘              │  living room)│
     │ WiFi                                       └──────────────┘
     ▼
┌──────────┐  emulated_hue  ┌───────┐
│  Home    │◄──────────────►│ Alexa │
│Assistant │                └───────┘
└──────────┘

Setup

1. Prerequisites

• ESPHome 2025.12.0+ (native CC1101 support)
• Home Assistant with ESPHome addon
• NodeMCU with ESPHome already flashed

2. Configure secrets

Copy and edit the secrets file:

cp secrets.yaml.example secrets.yaml
# Edit with your actual WiFi password, API key, etc.

3. Deploy

Upload config to HA and flash via ESPHome dashboard:

scp radio-controller.yaml ha:/homeassistant/esphome/radio-controller.yaml

Then open ESPHome dashboard in HA and click Install → Wirelessly.

4. Sniff RF codes

Open ESPHome logs and press buttons on your RF remotes. Look for entries like:

[rf_monitor] RC Switch: protocol=1 code=0x353FC0

5. Alexa integration

Bedroom lights are exposed via emulated_hue through input_boolean.bedroom_light in HA with automations that trigger the ESPHome button presses.

RF Signal Discovery

The device logs all received 433MHz signals for identifying nearby devices (weather stations, door sensors, etc.):

• Counter sensor — "RF Signals Received" tracks daily activity (resets at midnight)
• Last code sensor — "Last RF Code" shows the most recent protocol + code
• Repeating codes every 30-60s are likely weather stations
• Codes appearing on events (door open/close) are likely contact sensors

3D Printed Case

Parametric OpenSCAD enclosure in case/radio-controller-case.scad. Fits NodeMCU v2 + CC1101 with SMA antenna.

Assembled preview	Print layout (bottom + lid)

• Mounting posts for both boards (M2 screws)
• Micro-USB cutout for power/programming
• SMA antenna hole for external antenna
• Snap-fit lid with alignment lip
• Ventilation slots on bottom, top, and sides
• No supports needed — print bottom and lid flat

Open in OpenSCAD, set mode = "preview" to see assembled view or "print" for print layout. Adjust tol parameter for your printer.

Project Structure

radio-controller/
├── radio-controller.yaml          # ESPHome configuration
├── secrets.yaml                   # WiFi/API credentials (git-ignored)
├── case/
│   └── radio-controller-case.scad # 3D printable enclosure (OpenSCAD)
├── HOWTO.md                       # Development notes
└── README.md

Known Issues

• Living room lights (protocol 3) — TX codes captured but lights don't respond; original remote also broken, likely receiver pairing issue
• Protocol 2 noise — RF interference generates ~2-3 spurious protocol 2 code=0x0 signals per minute; filtered in lambda
• WiFi signal — Marginal at -65 to -74 dBm; mitigated with power_save_mode: none and max TX power