I'm wanting to have a set of LEDs turn on when I enter a

>>940337
PIR modules usually work like switches. They usually have a separate power line and an NO/NC circuit (used mainly for security) or a mains relay. Which one do you have?

>>940349
I have an HC-SR501, it has 3 pins, +,- and something else.
The circuit will be powered by batteries so I don't want a mains relay.

I would try just slapping it together to see if it works but I don't want to accidentally fry the sensor.

so basically a motion sensor? you can get one of those cheap outdoor light fixtures for your yard that turn on when someone walks by... and just rip out the sensor...

but the problem with room sensors is when the motion stops the lights will go out... so if you are sitting watching tv or something the lights will keep going off
or if you are doing your homework or anything that you arent moving around

>>940337
Be prepared to poop in the dark, bud. Turn that timer wayyy up

File: cordless outdoor motion sensor LED light.jpg (4KB, 180x180px) Image search: [Google]

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you're trying to re-invent the wheel. there's a million models already out there. i bought 6 when they went on special for $5 at Zellers.

File: HCSR501.jpg (42KB, 650x648px) Image search: [Google]

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>>940353
see pic related. I'd recommend what >>940477 said though, it just works like a mains switch. Much easier to use for your application.