Using With Sonoff 4CH

esphomeyaml can also be used with Sonoff 4CH wireless switches. These devices are basically just an ESP8266 chip with 4 relays to control power output, a few buttons on the top and a few status LEDs.

../../_images/sonoff_4ch_header.jpg

Sonoff 4CH WiFi switch.

This guide will step you through setting up your Sonoff 4CH and flashing the first esphomeyaml firmware with the serial interface. After that, you will be able to upload all future firmwares with the remote Over-The-Air update process.

Note

If you’ve previously installed Sonoff-Tasmota on your Sonoff 4CH, you’re in luck 😀 esphomeyaml can generate a firmware binary which you can then upload via the Tasmota web interface. To see how to create this binary, skip to Step 3: Creating Firmware.

Since firmware version 1.6.0, iTead (the creator of this device) has removed the ability to upload a custom firmware through their own upload process. Unfortunately, that means that the only way to flash the initial esphomeyaml firmware is by physically opening the device up and using the UART interface.

Warning

Opening up this device can be very dangerous if not done correctly. While the device is open, you will be a single touch away from being electrocuted if the device is plugged in.

So, during this entire guide never ever plug the device in. Also, you should only do this if you know what you’re doing. If you, at any step, feel something is wrong or are uncomfortable with continuing, it’s best to just stop for your own safety.

It’s your own responsibility to make sure everything you do during this setup process is safe.

For this guide you will need:

  • Sonoff 4CH 😉
  • An USB to UART Bridge for flashing the device. These can be bought on Amazon for less than 5 dollars. Note that the bridge must be 3.3V compatible. Otherwise you will destroy your Sonoff.
  • Jumper wires to connect the UART bridge to the header pins.
  • Computer running esphomeyaml or HassIO add-on.
  • Screwdriver to open up the Sonoff 4CH.

Have everything? Great! Then you can start.

Step 1: Opening up the Sonoff 4CH

The first step is to open up the Sonoff 4CH. Note that you do not have to run the original firmware supplied with the Sonoff 4CH before doing this step.

Warning

Just to repeat this: Make absolutely sure the device is not connected to any appliance or plugged in before doing this step.

While the device is not plugged in, turn the device so you are viewing it from the top, then unscrew the long screws in the four corners of the top cover.

../../_images/sonoff_4ch_top.jpg

There are four screws on the front of the Sonoff 4CH.

After that, you should be able to remove the front cover and should be greeted by the main board. The chip we’re interested in here is the “big” one encased in an aluminium cover.

../../_images/sonoff_4ch_mcu.jpg

The main chip of the Sonoff 4CH and the header pins we’re going to use to flash our custom firmware.

Step 2: Connecting UART

Now we need our computer to somehow establish a data connection to the board. For this we will have to connect the four wires on the UART to USB bridge to the UART pins of the Sonoff 4Ch.

Fortunately for us, exactly these pins come pre-populated with a few header pins. You can identify these by the VCC33, RX, TX and GND markings on the silk-screen.

Now go ahead and connect these pins to your UART to USB bridge as seen in below image. Make sure that you connect these correctly, especially the VCC33 and GND parts as you can otherwise destroy the chip.

VCC33 should be connected to the 3V3 (not 5V) pin of the UART bridge, GND to GND and the same with RX/TX.

When you’re done, it should look something like this:

../../_images/sonoff_4ch_uart.jpg

Note

On some older 4CHs, the RX and TX pins are swapped (sometimes even the written silkscreen is wrong). If your upload fails with a error: espcomm_upload_mem failed message it’s most likely due to the pins being swapped. In that case, just swap RX and TX and try again - you won’t break anything if they’re swapped.

Step 3: Creating Firmware

The Sonoff 4CH is based on the ESP8266 platform (technically it’s the ESP8285, but for our purposes they’re the same) and is a subtype of the esp01_1m board. With this information, you can step through the esphomeyaml wizard (esphomeyaml sonoff_4ch.yaml wizard), or alternatively, you can just take the below configuration file and modify it to your needs.

If you go through the wizard, please make sure you manually set board_flash_mode to dout as seen below. The version of the uploader used by esphomeyaml should automatically detect that the Sonoff 4CH uses the dout SPI flash chip mode. But, as some users of other firmwares have said that other flash modes can brick the device, it’s always good to specify it explicitly.

esphomeyaml:
  name: <NAME_OF_NODE>
  platform: ESP8266
  board: esp01_1m
  board_flash_mode: dout

wifi:
  ssid: <YOUR_SSID>
  password: <YOUR_PASSWORD>

mqtt:
  broker: <YOUR_MQTT_BROKER>
  username: <YOUR_USERNAME>
  password: <YOUR_PASSWORD>

logger:

ota:

Now run esphomeyaml sonoff_4ch.yaml compile to validate the configuration and pre-compile the firmware.

Note

After this step, you will be able to find the compiled binary under <NAME_OF_NODE>/.pioenvs/<NAME_OF_NODE>/firmware.bin. If you’re having trouble with uploading, you can also try uploading this file directly with other tools.

Step 4: Uploading Firmware

In order to upload the firmware, you’re first going to need to get the chip into a flash mode, otherwise the device will start up without accepting any firmware flash attempts. To do this, while the device is UART bridge is not connected to your USB port, start pressing the bottom-left push button labeled FW/IO0 and continue to do so while plugging in the UART bridge into your computer. Keep holding the button for another 2-4 seconds. The 4CH should now be in a flash mode and should not blink with any LED.

../../_images/sonoff_4ch_buttons.jpg

You need to press the button labeled FW/IO0 during startup.

Now you can finally run the upload command:

esphomeyaml sonoff_4ch.yaml run

If successful, you should see something like this:

../../_images/sonoff_4ch_upload.png

Hooray 🎉! You’ve now successfully uploaded the first esphomeyaml firmware to your Sonoff 4CH. And in a moment, you will be able to use all of esphomeyaml’s great features with your Sonoff 4CH.

If above step does, however, not work, here are some steps that can help:

  • Sometimes the UART bridge cannot supply enough current to the chip to operate, in this case use a 3.3V supply you have lying around. A nice hack is to use the power supply of NodeMCU boards. Simply connect the NodeMCU’s 3.3V to VCC and GND to GND. Do not attempt to plug the device into a socket to overcome this problem while troubleshooting.
  • In other cases the TX and RX pin are reversed. Simple disconnect the device, swap the two pins and put it into flash mode again.

Step 5: Adding the Button, Relay and LEDs

Now we would like the 4CH to actually do something, not just connect to WiFi and pretty much sit idle.

Below you will find a table of all usable GPIO pins of the Sonoff 4CH and a configuration file that exposes all of the basic functions.

GPIO0 Button #1 (inverted)
GPIO9 Button #2 (inverted)
GPIO10 Button #3 (inverted)
GPIO14 Button #4 (inverted)
GPIO12 Relay #1 and red LED
GPIO5 Relay #2 and red LED
GPIO4 Relay #3 and red LED
GPIO15 Relay #4 and red LED
GPIO13 Blue LED (inverted)
GPIO1 RX pin (for external sensors)
GPIO3 TX pin (for external sensors)
esphomeyaml:
  name: <NAME_OF_NODE>
  platform: ESP8266
  board: esp01_1m
  board_flash_mode: dout

wifi:
  ssid: <YOUR_SSID>
  password: <YOUR_PASSWORD>

mqtt:
  broker: <YOUR_MQTT_BROKER>
  username: <YOUR_USERNAME>
  password: <YOUR_PASSWORD>

logger:

ota:

binary_sensor:
  - platform: gpio
    pin:
      number: GPIO0
      mode: INPUT_PULLUP
      inverted: True
    name: "Sonoff 4CH Button 1"
  - platform: gpio
    pin:
      number: GPIO9
      mode: INPUT_PULLUP
      inverted: True
    name: "Sonoff 4CH Button 2"
  - platform: gpio
    pin:
      number: GPIO10
      mode: INPUT_PULLUP
      inverted: True
    name: "Sonoff 4CH Button 3"
  - platform: gpio
    pin:
      number: GPIO14
      mode: INPUT_PULLUP
      inverted: True
    name: "Sonoff 4CH Button 4"
  - platform: status
    name: "Sonoff 4CH Status"

switch:
  - platform: gpio
    name: "Sonoff 4CH Relay 1"
    pin: GPIO12
  - platform: gpio
    name: "Sonoff 4CH Relay 2"
    pin: GPIO5
  - platform: gpio
    name: "Sonoff 4CH Relay 3"
    pin: GPIO4
  - platform: gpio
    name: "Sonoff 4CH Relay 4"
    pin: GPIO15

output:
  # Register the blue LED as a dimmable output ....
  - platform: esp8266_pwm
    id: blue_led
    pin: GPIO13
    inverted: True

light:
  # ... and then make a light out of it.
  - platform: monochromatic
    name: "Sonoff 4CH Blue LED"
    output: blue_led

Above example also showcases an important concept of esphomeyaml: IDs and linking. In order to make all components in esphomeyaml as much “plug and play” as possible, you can use IDs to define them in one area, and simply pass that ID later on. For example, above you can see an PWM (dimmer) output being created with the ID blue_led for the blue LED. Later on it is then transformed into a monochromatic light. If you additionally want the buttons to control the relays, look at the complete Sonoff 4CH with automation example.

Upload the firmware again (through OTA or Serial) and you should immediately see something like this in Home Assistant because of esphomeyaml’s automatic MQTT discovery. (You’ll of course have to add them to groups if you have a default_view set):

../../_images/sonoff_4ch_result.png

Step 6: Finishing Up

If you’re sure everything is done with the 4CH and have double checked there’s nothing that could cause a short in the case, you can put the front cover with the button on the base again and screw everything together.

Now triple or even quadruple check the UART bridge is not connected to the 4CH, then comes the time when you can connect it.

Happy hacking!