I’m looking for a Zigbee-based, mains-powered solution to detect a wired doorbell button, which is a true dry contact (two wires that close when pressed, no voltage on the button).
I would like to :
• detect the button press in Home Assistant
• trigger a sound on a Google speaker
Constraints:
• Zigbee only (no Wi-Fi)
• powered, no battery
• must be a real input (binary_sensor), not a relay/output
I’ve been pointed toward modules sold as “Zigbee Dry Contact” (Tuya / Zemismart / Moes), powered , with IN/COM terminals, supposedly exposing an ON/OFF state in Home Assistant via Zigbee2MQTT.
Can anyone confirm that these devices are true inputs, meaning that closing the dry contact is actually detected and reported as a binary_sensor in Home Assistant?
For context:
• I already use Zigbee modules with multiple COM terminals for my irrigation solenoid valves, but those clearly work as outputs (relay control), not as inputs/detection.
I want to avoid buying another actuator when what I really need is an input.
Thanks in advance for your feedback and for any concrete model references.
Shelly ZBMiniR2 has “detached relay mode”, which means that input is only reported into HA, but relay is not triggered. Shelly’s button is only reported as binary sensor in HA in that case. (if that’s what you’re looking).
You can still use relay for other things (lights…) by triggering it from HA.
What you basically want is a moisture sensor or a reed switch style door/window sensor. Yes, those are battery, but there are battery eliminator plug-in devices out there to replace the battery.
Those devices convert a physical action like a button push to a zigbee binary sensor.
I would look for something like that. I use a reed type door sensor to trigger off a dry contact that another device pushes every time a door opens. I just removed the reed switch and connected the wires to the device instead. Battery actually lasts over a year on that one and it’s a AAA.
