ESPHome-Devices

eWeLink PCIe Computer Remote (SANT-SUD01)

eWeLink PCIe Computer Remote (SANT-SUD01)

Device Type: misc
Electrical Standard: global

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.

Product Image

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.

ESP8285 PinUSB Serial PinComments
GGroundIf using a dedicated power supply with the USB programmer, make sure that the GND for the programmer and power supply are linked!
V3V3Connect to dedicated 3V3 1A power supply if encountering brown out
RxTX
TxRX

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.

# 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

PinFunctionNotes
GPIO0INPUTButton on module PCB, used by OEM firmware for WiFi config (inverted); also receives a ~2.5Hz signal when the PC is turned on
GPIO12OUTPUTWired to the PC power button / motherboard, to simulate pressing the power button
GPIO13OUTPUTStatus LED (inverted)

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).

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;
}
# 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
pin: GPIO12
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