eWeLink PCIe Computer Remote (SANT-SUD01)

Device Type: misc

Electrical Standard: global

Board: esp8266

A simple remote control/monitor device for use with standard PCs.

Installed between the power button and the motherboard, it's able to simulate pressing the power button. As the headers are connected directly together, there's no way to "lock out" the physical button as some similar devices offer. It uses the PCIe power rails to determine whether the host PC is turned on, but this is reported to the ESP by a secondary MCU which pulses GPIO0.

Flashing

The module has a convenient row of 2.54mm pitch throgh holes below the ESP8285 chip which provide power and serial communication for the ESP. To enter flashing mode, hold the "WiFi Configuration" button down while powering up the ESP.

Connect all 4 pins as indicated, hold the "WiFi Configuration" button down and then power up the device and then plug in the USB programmer. The module should immediately enter boot loader mode and should be "discoverable" with esptool.py.

While not strictly necessary, you may wish to backup the flash content before overwriting with ESPHome.

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# Confirm that you can "see" the module
❯ esptool.py --port /dev/ttyUSB0 chip_id

# Double check the type/size of the flash chip
❯ esptool.py --port /dev/ttyUSB0 flash_id

# Read out the flash; in this case, the `flash_id` command indicated that the ESP had 1MB of built in flash memory
❯ esptool.py --port /dev/ttyUSB0 read_flash 0x000000 0x100000 flash_backup.bin

GPIO Pinout

Basic Configuration

The configuration below covers just the basics for getting the core functionality (turning PC on/off and seeing its status) usable in ESPHome. Depending on your specific needs, more configuration may be needed. E.G.: most motherboards will interpret the power button being pressed for 5+ seconds to mean "shutdown now". Exposing GPIO12 to Home Assistant directly as a gpio switch may result in the PC powering off a few seconds after it's powered on.

As GPIO0 is shared by the "WiFi Configuration" button and the PC power status signal, the button isn't included in the config below; if you wish to use it in your configuration, you'll need to determine how to reliably discern a button press from the "PC is on" signal (which appears to be around 2.5Hz / 150 pulses per minute; a threshold of 60 pulses per minute is used here to ensure detection).

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substitutions:
  friendly_name: "My PC Power Control"
  friendly_name_short: "My PC"

  hostname: "my-pc-power-remote-control"

esphome:
  name: ${hostname}

  # Shows up in UI
  comment: "Remote power button for ${friendly_name_short}."

esp8266:
  # Specifically a 'ESP8285N08' with 1MB built in flash
  # See: https://docs.platformio.org/en/stable/boards/espressif8266/esp8285.html
  board: esp8285

logger:
  level: INFO

script:
  - id: regular_press
    mode: single
    then:
      - output.turn_on: out_relay
      - delay: .5s
      - output.turn_off: out_relay

status_led:
  pin:
    number: GPIO13
    inverted: True

sensor:
  - platform: pulse_meter
    id: power_status_pulses
    pin: GPIO0
    timeout: 5s

switch:
  - name: "${friendly_name_short} Power"
    id: sw_pc_power
    platform: template
    lambda: |-
      if (id(power_status_pulses).state > 60.0f) {
        return true;
      } else {
        return false;
      }

#Replace the lambda function above with the one below if you have inverted the relay output
#    lambda: |-
#      if (id(power_status_pulses).state > 60.0f) {
#        return false;
#      } else {
#        return true;
#      }

    # Mimic the user pressing the button
    turn_on_action:
      - script.execute: regular_press
    turn_off_action:
      - script.execute: regular_press

output:
  - platform: gpio
    id: out_relay
    #Inverts relay operation, this avoids force shutdown behavior on some motherboards. Uncomment here and replace the above lambda if you are having this problem.
    #inverted: True
    pin: GPIO12