Shelly Uni Doorbell - Not detecting button push

    Hi,

    I need some help trying to make my old doorbell smarter.

    My goal is to leave the doorbell working as it is now and not use Uni's outputs, but detect the doorbell button push and send MQTT message when that happens.

    The doorbell is Friedland type 4, and it's powered by a 12V AC transformer.

    The transformer is wired so that the doorbell always has 12V AC power. Also, the button connection (OF) has a constant 12V. When the doorbell button is pushed, that 12V goes down to about 3-4V and this change is what I'm trying to detect.

    The Uni is wired to ACC to T3 and N to 1. Uni's 7 is wired to OF.

    Uni is powered and working ok, but it's not detecting the button being pushed. :/

    Uni's manual says that AC below 12V is (0) low.

    uni doorbell.drawio(1).png

    Here is an image of the wiring.

    I would really appreciate any help or ideas!

    Thanks! :)

    Please insert a diode between terminal OF of Friedland Type 4 and wire/pin 7 of Shelly UNI. Cathode (ring) towards pin 7; anode towards terminal OF. Diode may be a common type e.g. 1N4158 or 1N400x. After that Shelly UNI should detect the push of the button. Perhaps the signal is reversed (active with no push, inactive with push). In this case, “button type” has to be set to “reverse input” in the appropriate menue of Shelly UNI.

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)

    An alternative for solving the (possible) issue with reverse indication of button state would be to interchange Shelly’s power terminals: Connect line Vcc of Shelly UNI to terminal 1 of Friedland doorbell and line GND of UNI to T3 of the bell.

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)

    Hi,

    thanks for your suggestions thgoebel.

    Unfortunately, neither of them worked. Since the voltage (measured ~13,5V AC) is constant in OF of doorbell and push-button pulls this down to 4-6V diode had no effect. When inserting the diode constant voltage to Uni's pin 7 lowered to about 10V and ringing the bell to about 3-4V.

    Changing the inputs of Uni had no effect.

    I have set up the button as "Detached switch" (tried also "Momentary") and "Reverse inputs" is selected as otherwise button shows always on.

    Correct if I'm wrong but Uni should detect the voltage change from 13V AC -> 5V ?

    Thanks again!

    Would you please draw a tiny sketch how you’ve connected the diode? Hope I could understand the issue better with this graphical hint…

    „Habt Geduld. Alle Dinge sind schwierig, bevor sie einfach werden!“ (aus Frankreich)

    „Nothing in life is to be feared, it is only to be understood.“ (Marie Curie, 1867-1934)

    „Es reicht nicht“, rief Schiller, „Gedankenfreiheit zu fordern, man muß auch denken können, sonst fordert man Gedankenlosigkeitsfreiheit und die ist die Freiheit zur Dummheit, welche wiederum die schlimmste Unfreiheit überhaupt ist!“
    (Aus „Besuch aus Weimar“ von Gert Heidenreich, Schriftsteller, *1944 in Eberswalde)

  • Dieses Thema enthält 18 weitere Beiträge, die nur für registrierte Benutzer sichtbar sind, bitte registrieren Sie sich oder melden Sie sich an um diese lesen zu können.