I have some lights that go into the wall, that I've plugged into this smart outlet so I can control these through my phone. I want to also be able to power them through a movement activated sensor.

So it would either be a button on my phone telling it to be always on, or someone being present in the garden activating it while it's off.

Is such design possible?

  • 1
    \$\begingroup\$ One obvious answer would be to get a motion sensor that is compatible with your "smart outlet". \$\endgroup\$
    – Dave Tweed
    Jun 12, 2018 at 11:03

2 Answers 2


Is such design possible?

Yes, such a design is possible.

The problem is that it's not going to be easy to ensure safety.

  • Your solution is going to require correct phasing of the plugs in both devices (L to L, N to N) or short-circuit will occur.
  • The big problem is that if one plug is in and on the other will be live.


simulate this circuit – Schematic created using CircuitLab

Figure 1. The live plug pins problem.

I advise you against combining the products in this way.


This can be done with relays, but you will need to wire them up safely. A relay is a kind of switch which output closes when an input coil is powered. In this application, two relays with both output going to the lights would work. The input coils would each be wired to their respective devices, and they would never meet in an electrical sense as the relays are separate.

The smart outlet would need to be wired up to the relays, which can be done by plugging in a mains plug with a free ends cable and using the free ends of the cable to connect to the relays.

Please be cautious if you do decide to proceed with such a project. Mains electricity is very dangerous and can easily harm you or start a fire. If you feel you are not experienced enough, please seek professional help.


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