Radio Controller

NodeMCU v2 ESP8266 development board with WiFi module and micro-USB connector

CC1101 433MHz RF transceiver module with SMA antenna connector

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.

Architecture

ESP8266 + CC1101 — NodeMCU v2 communicates with CC1101 RF transceiver over SPI, sharing a single GDO0 pin for both receiving and transmitting
ESPHome firmware — native CC1101 component handles 433.92MHz ASK/OOK modulation, RC Switch protocol encoding/decoding, and automatic RX/TX mode switching
Home Assistant — connects via encrypted native API, exposes buttons for each light control command
Amazon Alexa — voice control through emulated_hue bridge with input_boolean and automation triggers
RF monitoring — logs all received 433MHz signals with protocol and code for device discovery

Features

Bedroom lights (protocol 1) — Toggle, ON, OFF via Home Assistant buttons and Alexa voice commands
Living room lights (protocol 3) — 8 buttons: toggle, on, off, timers (30s/30min/60min)
RF signal monitoring — daily counter sensor, last received code sensor, all signals logged for discovery
Noise filtering — protocol 2 code=0x0 spurious signals filtered in lambda to reduce log clutter
WiFi hardening — fast_connect, power_save_mode disabled, max TX power for stable connection
3D printable case — parametric OpenSCAD enclosure with mounting posts, ventilation, and SMA antenna pass-through

Hardware

NodeMCU ESP8266 v2 — WiFi microcontroller running ESPHome firmware
CC1101 transceiver — 433.92MHz RF module with SMA antenna, connected via SPI (SCK, MISO, MOSI, CSN) plus GDO0 for data
SPI wiring — SCK→D5, MISO→D6, MOSI→D7, CSN→D8, GDO0→D2 (shared RX/TX)
Power — CC1101 runs at 3.3V from the NodeMCU regulator

3D Printed Case

Parametric OpenSCAD design — adjustable tolerances, wall thickness, and post dimensions
Mounting posts for both NodeMCU (4 corners) and CC1101 (2 posts) with M2 screw holes
Cutouts — micro-USB port for power/programming, SMA hole for external antenna
Snap-fit lid with alignment lip, ventilation slots on all sides
No supports needed — both parts print flat

Technical Details

Firmware: ESPHome 2025.12.0+ with native CC1101 component (YAML + C++ lambdas)
RF protocol: 433.92MHz ASK/OOK, RC Switch protocols 1 and 3
Communication: SPI bus for CC1101, encrypted native API for Home Assistant
Voice control: emulated_hue bridge exposing input_boolean entities to Alexa
Monitoring: WiFi signal sensor, uptime counter, RF signal counter (resets daily), last code text sensor
3D case: OpenSCAD parametric design, ~90 x 30 x 16 mm external dimensions

Check out the project on GitHub: Radio Controller on GitHub

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