FAQ
TL;DR: Add voice control by wiring a dry-contact Wi‑Fi relay (Sonoff SV; 5–24 V DC) in parallel with JP81. "Input voltage from 5V DC to 24V DC." Power it from the intercom’s 18 V DC and use Supla for Google Assistant/Siri. [Elektroda, DomR, post #19266673]
Quick Facts
- Sonoff SV accepts 5–24 V DC and provides a voltage-free NO relay rated up to 3 A, ideal for gate triggers. [Elektroda, DomR, post #19266673]
- Wire the relay in parallel across the intercom’s NO and COM gate terminals to retain panel control. [Elektroda, sosarek, post #19266742]
- Final build worked without adding a diode when powered from 18 V DC. [Elektroda, DomR, post #19282219]
- If the panel only offers AC, power the Wi‑Fi relay from a separate 5–24 V DC source. [Elektroda, sosarek, post #19266498]
- Supla enabled voice control with Google Assistant and Siri in English, without IFTTT. [Elektroda, DomR, post #19282219]
How do I add Google Assistant control to my intercom-controlled gate?
Use a low‑voltage, dry‑contact Wi‑Fi relay at the intercom. Power it from the 18 V DC line. Connect its relay to the gate trigger terminals. Then configure the relay in the Supla app and link voice control with Google Assistant or Siri. The reported setup worked without IFTTT. [Elektroda, DomR, post #19282219]
Will the intercom panel button still work after adding the Wi‑Fi relay?
Yes. Wire the relay across the same NO and COM gate terminals. This preserves the panel’s physical button operation. The working build confirmed parallel control with the intercom button and app. [Elektroda, DomR, post #19282219]
Is Shelly 1 suitable here, or do I need a dry-contact relay?
Avoid 230 V powered modules at the low‑voltage intercom panel. Use a device that offers a potential‑free contact on the output. That matches the gate trigger input and avoids bringing mains to the panel. [Elektroda, sosarek, post #19266442]
Is Sonoff SV compatible with 18 V DC gate systems?
Yes. Its stated specs include “Input voltage from 5V DC to 24V DC” and “Relay - load up to max 3A.” This covers an 18 V DC supply and typical low‑current trigger inputs. [Elektroda, DomR, post #19266673]
Do I need a diode between NO and COM when wiring in parallel?
No. A diode does not provide galvanic isolation for control circuits. The relay’s dry contacts already isolate the control side. As one expert noted, “what is the use of a relay, transformer or optocoupler here?” Keep the wiring clean and direct. [Elektroda, sosarek, post #19277985]
How do I wire this without losing the intercom button?
Use parallel wiring on the gate trigger.
- Identify the intercom’s NO and COM gate terminals.
- Connect the Wi‑Fi relay’s NO and COM across those same terminals.
- Leave the original button wiring intact so both controls work. [Elektroda, sosarek, post #19266742]
Can I power Sonoff SV directly from the intercom’s 18 V DC line?
Yes. The module accepts 5–24 V DC, so 18 V is within range. Verify polarity and use the low‑voltage input terminals. [Elektroda, DomR, post #19266673]
What if my intercom provides only AC power?
Do not power a DC‑only relay module from AC. Use a separate 5–24 V DC supply for the relay. Then connect its dry contacts in parallel with the gate terminals as before. [Elektroda, sosarek, post #19266498]
Can I use Sonoff RE5V1C instead?
Yes. Power the RE5V1C at 5 V DC from a separate supply. Use its voltage‑free relay contacts across the intercom’s gate terminals. The intercom’s 18 V line does not need to power the relay. [Elektroda, sosarek, post #19266498]
How do I integrate with Siri or Google Assistant without IFTTT?
Add the relay to the Supla app and enable voice control integration. The reported setup worked with Siri and Google Assistant using English commands. It did not require IFTTT. [Elektroda, DomR, post #19282219]
Is this module CE‑marked and safe to install as‑is?
The referenced module listing notes “CE - none” and states it is a bare board for custom projects. Mount it in a suitable enclosure and follow local standards accordingly. [Elektroda, DomR, post #19266673]
Any tips for garage doors or position feedback?
A similar working build used a Sonoff 7–32 V volt‑free module for a garage door. It added reed switches for status and ran under Supla. [Elektroda, DomR, post #19282219]
