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I need help with a sensor problem.

fitzy

Feb 19, 2010
5
Joined
Feb 19, 2010
Messages
5
Hi,
is it possible to use the motion sensor in a security sensor light to switch an electrical appliance off?
Instead of switching the security light on, i need the motion sensor wired to something to switch an appliance off. Is this possible? If so, what item would i need to wire between the sensor and the appliance?
Thank you,
Fitzy
 

davenn

Moderator
Sep 5, 2009
14,271
Joined
Sep 5, 2009
Messages
14,271
Hi,
is it possible to use the motion sensor in a security sensor light to switch an electrical appliance off?
Instead of switching the security light on, i need the motion sensor wired to something to switch an appliance off. Is this possible? If so, what item would i need to wire between the sensor and the appliance?
Thank you,
Fitzy

Hi Fitzy,
yes its possible. most PIR sensor units have a pair of relay contacts that close when motion is detected. If you are wanting to switch off a mains powered device (110 or 240VAC) then you could use that relay to drive a solid state relay that can handle the voltage and current that the device uses. If its a mains voltage load then you could use a SY4084, load ratings 40A, 240V, it can be driven by any voltage between 4 and 32VDC.

so the relay in the PIR detector will drive the SS relay using a low voltage supply say 12VDC.
Use the normally open contacts on the PIR relay if you want to switch something on
Use the normally closed contacts on the PIR relay if you want to switch something off

cheers
Dave
 
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