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A safer way for Makers and DIY'ers to control mains ac power with a microcontroller.

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PowerState Tail
(PN 80155)
 $34.99 each 

 In Stock!


A power cord that detects when a 120vac appliance is on or off.



  • Detects when a connected 120vac load/device/appliance is off (power consumption < 10 watts) or on (power consumption > 10 watts.
  • Easily inserts between the power source (outlet) and any 120vac load/device/appliance.
  • Output is isolated relay contacts (NC-COM-NO). COM and NO contacts close when threshold is exceeded. Relay contacts may be connected to a microcontroller input pin or used to power another device using an external power source.
  • 1,500vac isolation between powered appliance and output contacts.
  • No separate power supply needed. Powered from the ac line (approx. 1 watt).
  • Built-in LED turns on when power detection threshold is exceeded.
  • No exposed 120vac voltages and no dangerous 120vac wiring required. Can be installed by non-technical users: Instruction sheet.
  • Plugs into standard 120vac 3-prong household outlets, power strips, and extension cords.



  • AC input: NEMA 5-15P Plug, standard 120vac with ground.
  • AC output: NEMA 5-15R Receptacle, standard 120vac with ground.
  • Monitoring capacity: 1800 watts or 15 amps @ 120vac.
  • Detection threshold: 10 watts, non-reactive. (Custom thresholds available.)
  • Detection burden: Negligible; 1.2 milliohm sense resistor.
  • Output: Isolated relay contacts, normally open, common, normally closed. Contacts rated for .5 amp @ 120vac.
  • Output to ac circuit isolation: 1,500vac.
  • Power consumption: Approx. 1 watt from 120vac line.
  • Indicator: LED indicates when detection threshold is exceeded.
  • Mounting: Two #6 screws or free standing.
  • Indoor use only.



Highly reactive loads and some switching power supplies may cause false detection causing the relay and LED to flicker when the monitored load is close to the detection threshold. Contact us if special detection thresholds are required.

Our liability is limited to the purchase price of this product only. By using this product you agree that, LLC can not be held liable for any damages or injuries resulting from use, misuse, or repair. This product is for indoor use only.