No voltage contacts with ESPHome

ESPHome
1

I have a Mitsubishi aircon unit that I’d like to connect to and read a no voltage contact to detect if there is a fault status.

It has a PACSF40-RM-E Remote Operation Adaptor connected to it which has two no voltage contacts.

Can I read these with an ESP8266/ESP32? Do I need additional components or can the board do it itself? Could anyone point me to an example of the config for this?

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2

Yes you can connect it. No you don’t need any other components. Just use the software enabled pull up or down resistors.

If you use an ESP32 you can even connect an output directly to the TB3 input (if it is any use) by setting the GPIO output mode to open drain.

EDIT: actually this is a weird specification:

image

The ESP input load will be considerably less than 10mA. My bet is it will still work though.

3

Yes.
You only need to wire your Esp gpio with external pull-up to contact and from there to GND

Edit: tom_I was quicker :wink:.

4

I just edited my post. What do you reckon about the “minimum load” specification?

5

All switches and relays have minimum contact current. Here they tell 10mA, but it can work with 0.1mA as well (not guaranteed). Using 330ohm pullup would give 10mA load.

6

So something like this?

binary_sensor:
  - platform: gpio
    pin:
      number: D1
      mode: INPUT_PULLUP
      inverted: True
    name: "Aircon-1-Fault"
    device_class: problem
  - platform: gpio
    pin:
      number: D2
      mode: INPUT_PULLUP
      inverted: True
    name: "Aircon-1-Operation"
    device_class: running
7

Looks good, add small on_off_delay to filter out false triggers.
Considering the high min current from manufacturer, the relay contacts are cheaply made and you should consider external pullup resistors to have reliable operation also in future. 1k pull-up would be my personal choice. That would give 3mA load .