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cc1101-transceiver

ESPHome config for CC1101 RF Transceiver

A complete ESPHome configuration for the CC1101 Sub-1 GHz RF Transceiver with an ESP32-C3, featuring signal learning, replay, and Home Assistant integration.

Learn and replay 433 MHz RF signals from remotes, blinds, outlets, and more — directly from Home Assistant.

Features

  • Learn RF signals — Capture signals from any 433 MHz remote
  • Replay signals — Retransmit learned signals on demand (single or x3)
  • Single-line log output — Captured codes logged as copyable arrays
  • Dual pin wiring — Simultaneous TX/RX without mode switching
  • Home Assistant integration — Full control via buttons, switches, and sensors
  • Web interface — Built-in web server on port 80 for standalone use

Hardware Requirements

Component Description
ESP32-C3-DevKitM-1 Espressif ESP32-C3 development board (or any ESP32-C3 board)
CC1101 Module 433 MHz version (common green or blue PCB modules)
Jumper Wires 8 female-to-female dupont wires
Antenna 433 MHz antenna (17.3 cm wire or SMA antenna)

Note: The ESP32-C3-DevKitM-1 is recommended. Other ESP32-C3 boards (e.g. SuperMini, XIAO) should also work — verify your board's available GPIO pinout before wiring.

Wiring Diagram

Dual Pin Mode (Recommended)

Uses separate pins for TX and RX — no mode switching needed.

 ESP32-C3-DevKitM-1         CC1101 Module
 ┌──────────┐              ┌──────────────┐
 │          │              │              │
 │     3V3  ├──── Red ─────┤ VCC          │
 │     GND  ├──── Black ───┤ GND          │
 │          │              │              │
 │   GPIO5  ├──── Orange ──┤ MOSI (SI)    │
 │   GPIO3  ├──── Yellow ──┤ MISO (SO)    │
 │   GPIO4  ├──── Green ───┤ SCK (SCLK)   │
 │   GPIO0  ├──── Purple ──┤ CSN (CS)     │
 │          │              │              │
 │   GPIO1  ├──── Blue ────┤ GDO0 (TX)    │
 │   GPIO2  ├──── Cyan ────┤ GDO2 (RX)    │
 │          │              │              │
 └──────────┘              └──────────────┘
Wire ESP32-C3 Pin CC1101 Pin Function
Red 3V3 VCC Power (3.3V only!)
Black GND GND Ground
Orange GPIO5 MOSI SPI Data Out
Yellow GPIO3 MISO SPI Data In
Green GPIO4 SCK SPI Clock
Purple GPIO0 CSN SPI Chip Select
Blue GPIO1 GDO0 TX Data
Cyan GPIO2 GDO2 RX Data

⚠️ The CC1101 is a 3.3V device. Do not connect to 5V — it will damage the module.

Why these pins? On ESP32-C3, GPIO6–GPIO11 are internally connected to the SPI flash chip and must never be used for external peripherals. GPIO0–GPIO5 are the safest, most accessible alternative. See ESP32-C3 Pin Notes for details.

GPIO2 note: GPIO2 is a strapping pin on ESP32-C3, but it only controls JTAG debug port selection — it does not affect boot mode. It is safe to use for GDO2 in normal operation. If you experience issues, substitute GPIO10 (check your board's pinout first).

Pin numbering may vary between modules. Always verify with your module's datasheet.

ESP32-C3 Pin Notes

Why GPIO6–GPIO11 Are Forbidden

The ESP32-C3 routes its internal SPI flash through GPIO6–GPIO11 on the chip. Using any of these for an external peripheral will corrupt flash access, cause crashes, or prevent boot entirely.

GPIO Range Status
GPIO0–GPIO5 ✅ Safe — general purpose, broken out on DevKitM-1 header
GPIO6–GPIO11 ❌ Reserved — connected to SPI flash chip internally
GPIO12–GPIO21 ✅ Safe — general purpose (GPIO18/GPIO19 are USB D-/D+ on DevKitM-1)

Strapping Pins

ESP32-C3 samples three pins at boot to decide operating mode. If a connected peripheral drives these pins at an unexpected level during power-up it can affect boot or debugging.

GPIO Strapping Function Impact Safe as GDO2/CS?
GPIO2 JTAG source selection Affects debug port only — not boot mode ✅ Yes
GPIO8 ROM serial messages Cosmetic only ✅ Yes
GPIO9 Boot mode (HIGH = normal, LOW = download) Can enter download mode ⚠️ Avoid

This config uses GPIO2 for GDO2 (RX). CC1101's GDO2 goes low after power-up by default (chip-ready signal). This sets JTAG to the USB-JTAG interface — harmless for normal use; only relevant if you use hardware JTAG debugging.

Flashing

The ESP32-C3-DevKitM-1 has two USB ports:

Port Chip Use
UART (most boards: left port) CP2102N USB-to-UART First-time flashing, serial logs
USB (most boards: right port) Built-in USB-JTAG Alternative flashing, JTAG debugging

Connect via the UART port for esphome run or initial flashing. After first flash, OTA updates work over WiFi.

Installation

Prerequisites

  • ESPHome installed (via Home Assistant Add-on or standalone)
  • ESP32-C3 board with USB cable (connect to the UART/CP2102N port for first flash)
  • CC1101 module wired to ESP32-C3 per the table above

Usage

Learning a Signal

  1. Press "Learn Signal" in Home Assistant (or toggle "Learning Mode" on)
  2. Status shows "Waiting for signal... Press remote now!"
  3. Press the button on your RF remote near the CC1101
  4. Status updates to "Signal learned! X pulses captured"

Replaying a Signal

  • "Replay Learned Signal" — Transmit once
  • "Replay x3" — Transmit 3 times with 50ms gaps (more reliable for some devices)

Clearing the Signal

  • Press "Clear Learned Signal" to reset and learn a new one

Note: The learned signal is stored in RAM. It will be lost on reboot. See Adding Permanent Buttons to save signals permanently.

Copying Raw Codes from Logs

Every received signal is logged as a single copyable line in the ESPHome console:

[I][raw_code:xxx]: Pulses: 122
[I][raw_code:xxx]: Copy this line:
[I][raw_code:xxx]: [592, -635, 266, -295, 617, -615, 268, -309, ...]

You can paste this array directly into the YAML config as a permanent button.

Home Assistant Entities

Buttons

Entity Icon Description
Learn Signal mdi:record-rec Start learning mode
Replay Learned Signal mdi:replay Transmit learned signal once
Replay x3 mdi:replay Transmit 3 times with 50ms gaps
Clear Learned Signal mdi:delete Clear signal from memory
TX Test mdi:access-point Send a test signal
Restart Reboot the ESP32-C3

Switch

Entity Icon Description
Learning Mode mdi:school Toggle learning on/off

Sensors

Entity Type Description
Learn Status Text Current status message
Last Received Signal Text Preview of last captured signal
Learned Signal Length Number Pulse count of learned signal
Signal Learned Binary Whether a signal is currently stored

Adding Permanent Buttons

Once you've captured a signal from the logs, add it to the button: section in your YAML to make it permanent:

- platform: template
  name: "Living Room Blinds Up"
  icon: "mdi:blinds-open"
  on_press:
    - remote_transmitter.transmit_raw:
        carrier_frequency: 0Hz
        code: [592, -635, 266, -295, 617, -615, ...]

- platform: template
  name: "Living Room Blinds Down"
  icon: "mdi:blinds"
  on_press:
    - remote_transmitter.transmit_raw:
        carrier_frequency: 0Hz
        code: [605, -622, 280, -310, ...]

You can also wrap them in a repeat for reliability:

- platform: template
  name: "Garage Light"
  icon: "mdi:lightbulb"
  on_press:
    - repeat:
        count: 3
        then:
          - remote_transmitter.transmit_raw:
              carrier_frequency: 0Hz
              code: [500, -500, 500, -500, ...]
          - delay: 50ms

Automation Examples

Close Blinds at Sunset

automation:
  - alias: "Close Blinds at Sunset"
    trigger:
      - platform: sun
        event: sunset
    action:
      - button.press:
          entity_id: button.cc1101_rf_transceiver_living_room_blinds_down

Toggle Lights via Motion Sensor

automation:
  - alias: "RF Light on Motion"
    trigger:
      - platform: state
        entity_id: binary_sensor.hallway_motion
        to: "on"
    action:
      - button.press:
          entity_id: button.cc1101_rf_transceiver_hallway_light

Configuration Reference

CC1101 Settings

Adjust in the cc1101: section of the YAML:

Setting Value Description
frequency 433.92MHz Operating frequency (300–928 MHz)
output_power 10 TX power in dBm (-30 to +11)
modulation_type ASK/OOK Modulation scheme
symbol_rate 5000 Symbol rate in Baud
filter_bandwidth 200kHz Receive filter bandwidth

Remote Receiver Tuning

Setting Value Description
tolerance 50% How much pulse timing can deviate
filter 200us Ignore pulses shorter than this
idle 10ms Gap that marks end of a signal

Tuning tips:

  • Too much noise → increase filter to 500us or reduce filter_bandwidth
  • Missing signals → increase tolerance or idle

Troubleshooting

CC1101 Not Detected

  • "FF0F was found" error — SPI wiring issue. Double-check MISO (GPIO3), MOSI (GPIO5), SCK (GPIO4), and CSN (GPIO0) connections.
  • Verify you're using 3.3V, not 5V.
  • Use shorter jumper wires — long wires cause SPI failures.
  • On ESP32-C3: double-check that none of the wires are accidentally on GPIO6–GPIO11 (they share labels with adjacent header pins).

Not Receiving Signals

  • Confirm the remote operates on 433.92 MHz (some use 315 or 868 MHz).
  • Attach a proper antenna — a 17.3 cm straight wire works for 433 MHz.
  • On ESP32-C3: verify none of your wires are connected to GPIO6–GPIO11 (reserved for flash).
  • Try increasing filter_bandwidth to capture wider frequency deviations.

Signals Captured But Replay Doesn't Work

  • Use "Replay x3" — some devices need multiple transmissions.
  • Move the ESP32 + CC1101 closer to the target device.
  • Increase output_power to 11 (maximum).
  • Rolling code devices (garage doors, car key fobs) cannot be replayed — each press generates a unique code.

Too Much Noise in Logs

  • Increase filter from 200us to 500us
  • Reduce filter_bandwidth from 200kHz to 100kHz
  • Move the antenna away from the ESP32 board and USB cable

Compatible Devices

✅ Works (Fixed Code) ❌ Won't Work (Rolling/Encrypted)
Motorized blinds/shades Car key fobs
RF power outlets Most garage door openers
Ceiling fan remotes Security alarm systems
Doorbells
RF light switches
Fixed-code gate remotes

References

License

MIT License — free to use, modify, and share.

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ESPHome config for CC1101 RF Transceiver

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