I have spare sonoff mini and sonoff basic r2 switches.
Is there any safe way to connect it by 1/2 switches?
Or should I buy something else (esphome compatibile)?
I have to be sure that during power outtage (or reboot) the switch will not change it’s state - it will cut off garden irrigation during winter time.
Kind Regards
Maciek
Since the Sonoff Basic R2 devices do now have 2 pole switch contacts (ie: Normally open and normally closed) then there is no proper safe way to use ONLY once of those devices. The best solution (for safety) is to wire in a 2 pole relay to provide the N.O / N.C contacts.
Solid state relays??
They are not the ideal way to control your valve since these don’t have NC contact like normal relays. I’m not saying you can’t use them but you need to take care of the interlock on your code.
Also, some link or datasheet would be great, I’m not even sure they work at 3.3V trigger.
Yes to both questions. I’ll draw up a schematic a bit later for you but it’s very similar to my last one.
Basically just use the output off the Sonoff to power the coil of a relay. Be sure to get a relay with a 240 (or 230) V coil. Most relays of that sort with have both N.O. and N.C. contacts
One thing to be aware of here is that there is a constant 240V going to the relay COMMON even when the Sonoff is OFF so you will need to ensure there is a suitable upstream isolation point and that of course all of this is suitably protected by an RCD and enclosed etc.