RFLink ESP

This is a Radio Frequency to MQTT/Serial/TCP gateway built for ESP32 and ESP8266 boards (see #MCU for more).

It receives and decodes OOK 433MHz signals from your sensors, alarms and pushes them over MQTT/TCP/Serial. For some devices it can also send commands to control them.

This project is forked from RFLink-ESP (for ESP8266), which itself is forked from the original RFlink project "Release 29" for Arduino.

This fork provides additional features:

• Fully (almost) configurable from a web interface whilst retaining the CLI.
• No recompilation for most options which are configurable at runtime and saved in Flash.
• More advanced debugging and troubleshooting helpers.
• Restructured source code with namespaces and classes (Work in Progress)

1. MCU

We extensively use ESP32 dev kits. This is the default settings in Platformio.ini and RFLink.h files.

You may also use other ESP8266/ESP8255 based boards when there are no pin limitations. NodeMCUv2 is known to work.

2. Receiver / Transmitter / Transceiver

As a starting point, you can use the RXB6 receiver which is a simple and stable 3.3v component - it is easy to find and cheap. Many other receivers are also supported.

Avoid using generic noname receivers!

For more advanced behavior and reliability, the following receivers are also supported when used with an ESP32 board:

• SX1278
• SX1276
• RFM69CW
• RFM69HCW
• CC1101

These advanced receivers require a few pins to be connected to the host. The recommended pin assignments are:

Name	ESP32	SX1278/6	RFM69(H)CW	CC1101
	3v3	VCC	3.3V	VCC
	GND	GND	GND	GND
	18	SCK	SCK	SCK
	19	MISO	MISO	MISO
	23	MOSI	MOSI	MOSI
pins::RX_RESET	4¹	NRESET	RESET
pins::RX_CS	5¹	NSS	NSS	CSN
pins::RX_DATA pins::TX_DATA	26¹	DIO2	DIO2	GDO0

¹ These must be configured in the web portal, values suggested here are proven to work reliably.

3. OLED display

You can use an OLED display. We used a SSD1306 128x64 I2C screen in our tests.

This is highly experimental and therefore not enabled by default.

4. IDE

We strongly recommend using the PlatformIO IDE but you can alternatively use the Arduino IDE 1.8.10.

5. Framework

We use Arduino Core for ESP8266.

6. Libraries

In addition to the core libraries, the following are also in use:

• PubSubClient for MQTT messaging https://github.com/knolleary/pubsubclient
• u8g2/u8x8 library for OLED display https://github.com/olikraus/u8g2

7. Compile Options and Flags

Many features are not enabled by default or can be disabled for various reasons like firmware size or compatibility.

OTA (disabled by default)

There are 3 types of OTA to update your firmware:

Arduino/ESP's classic push over UDP (disabled by default)

• RFLINK_OTA_ENABLED we recommend that you enable a password for this method or anyone on your network could push a new firmware to the device.
• RFLINK_OTA_PASSWORD="my_password_here" or RFLINK_OTA_PASSWORD='"'${sysenv.OTA_SEC}'"' in platformio.ini with an environment variable called OTA_SEC

AutoOTA

The device will download new firmware from a specified URL.

• RFLINK_AUTOOTA_ENABLED
• AutoOTA_URL in Credentials.h or in platformio.ini

Config Portal Web Upload

A firmware file can be uploaded via the Config Portal's Firmware page.

8. Additional Info

Config Portal

Repository

The Config Portal web ui is located in its own repository.

Default Login Details

rflink32 / 433mhz

Pinout

• Pin setup has to be done via the Config Portal when it is active.
• For safety and simplicity all pins are inactive by default.
• Decoupling capacitors and antenna can be added to improve results.

Simple RX pin wiring:

Name	D1 mini	RXB6
PIN_RF_TX_VCC	D5	5 VCC
PIN_RF_TX_NA	D6	6 DER
PIN_RF_TX_DATA	D7	7 DAT
PIN_RF_TX_GND	D8	8 GND

Alternative Pinout

• ESP8266 can't draw more than 12mA on a GPIO pin.
• Some receivers have current spikes bigger than that (eg RXB12).
• This leads to a non working receiver or non starting ESP.

Safe alternative wiring:

Name	D1 mini	RXB6
PIN_RF_TX_VCC	3v3	5 VCC
PIN_RF_TX_NA	N/A	6 DER
PIN_RF_TX_DATA	D7	7 DAT
PIN_RF_TX_GND	GND	8 GND

Thanks

Special thanks to: Axellum, Etimou, Schmurtz, Zoomx