Author Options:

Extremely urgent!! I need help figuring out how to connect an alarm to a PIR sensor! Answered

Skip to the second paragraph if you are short on time or get sick of me droning on.

             Okay, so you've just done the first step in helping me, reading this.  Me and my dad are sick of having our pumpkins trashed on Halloween just because someone doesn't like our football team. (there are other reasons too but that could take a whole book and a month to explain it)  We live in a nice neighborhood where everybody knows everyone and things are pretty nice.  However there are some people in our neighborhood who just don't give a freaking crap what their kids do, and I'm sick of it.
               So I have a PIR sensor, Ladyada explaining how to use them, RadioShack, and Adafruit Industries.  I also have an extremely loud alarm that goes off when the circuit is broken.  I need some help figuring out how to make the PIR sensor break the circuit on the alarm.  I have included a diagram explaining.



Best Answer 6 years ago

Here is a quick wire using a 5Volt reed SPDT relay
Available from Digi-Key. . . . . A


Hmm, would work except I need a solution by tommorow. Do you have any ideas that can be made out of stuff I probably have lying around?

Do you have a relay ?
what voltage is the relay ?
Do you have any any NPN transistors ?
What voltage is the alarm box ?

I think I have it (https://www.instructables.com/id/Cheap-easy-motion-detecting-prop-dropper/?ALLSTEPS) , I just have one question, what is the color code for a 120 ohm resistor?

for the project mentioned above, would I be able to use a 100 ohm resistor? If so good, if not, it should work anyway.

Probably can use a 100 if it gets smelly hot stop.

Black-Brown-Black-silver or gold => 120 ohms the gold or silver is %.