# Trigger a device ( if lamp is offline)

**URL:** <https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575>\
**Category:** Free discussion\
**Created:** [November 16, 2022, 8:54am UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575 "2022-11-16T08:54:52Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![ociepa.ekotox](https://avatars.discourse-cdn.com/v4/letter/o/c68b51/32.png) [@ociepa.ekotox](https://forum.ewelink.cc/u/ociepa.ekotox)\
**Post date:** [February 26, 2025, 2:46pm UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575/23 "2025-02-26T14:46:12Z")

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Mechanically, this can be solved in this way. The lack of power supply to the device ( A ) causes a change in the state of the 4CHR Pro device relay, which causes a change in the state on the S2 connector of the device B. (e.g. device ZBMINIR2, MINIR4, MINIR4M ).  
Device B must have a separate power supply.

 ![sonoff 4chpror_minir4](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/5/5756126b37a4e099362b2665c476e251bd60158a.jpeg)

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**Author:** ![renatoyamane](https://avatars.discourse-cdn.com/v4/letter/r/e95f7d/32.png) [@renatoyamane](https://forum.ewelink.cc/u/renatoyamane)\
**Post date:** [February 26, 2025, 6:26pm UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575/24 "2025-02-26T18:26:58Z")

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> [@leblinux](#):
>
> does the 4CHPro detects offline-state of a channel and triggers a scene?

I don’t have it, but if you have a device that measure voltage/current (as some smart plugs), can you just create a scene like “_if current is lower than 50mA, then do something_”?

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**Author:** ![leblinux](https://avatars.discourse-cdn.com/v4/letter/l/838e76/32.png) [@leblinux](https://forum.ewelink.cc/u/leblinux)\
**Post date:** [February 26, 2025, 8:12pm UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575/25 "2025-02-26T20:12:10Z")

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Thank you!

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**Author:** ![leblinux](https://avatars.discourse-cdn.com/v4/letter/l/838e76/32.png) [@leblinux](https://forum.ewelink.cc/u/leblinux)\
**Post date:** [February 26, 2025, 8:12pm UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575/26 "2025-02-26T20:12:26Z")

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Thanks

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**Author:** ![leblinux](https://avatars.discourse-cdn.com/v4/letter/l/838e76/32.png) [@leblinux](https://forum.ewelink.cc/u/leblinux)\
**Post date:** [February 26, 2025, 8:23pm UTC](https://forum.ewelink.cc/t/trigger-a-device-if-lamp-is-offline/8575/27 "2025-02-26T20:23:29Z")

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If I have a relay like this can you show the connection to MINIR4; knowing Mini power supply is always connected to it but dunno how sw1 and sw2 should be connected the attached relay.

 ![image](https://europe1.discourse-cdn.com/flex005/uploads/ewelinkforum/original/2X/7/739c04592095b97eb14150ddd599983cd54318fa.jpeg)

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