Honestly, how many people have been in this scenario (leave a yes or no in the comments) : It is 2:30 in the morning and you wake up with a need to do something whatever that may be (bathroom, forgotten homework assignment, project due in 5 or 6 hours, etc.) it takes you 5-10 minutes to find the light switch (give or take...)

My mother likes a night light for the bathroom but she didn't want one that stayed on all night so I needed one that could detect a person. Many thoughts popped up into my head on what sensors to use. I could us esuch as the Linescan Imaging Sensor Daughterboard by Parallax but that was overkill and too expensive. A cheaper solution would be to use a few ir leds with ir phototransistor but still too complicated. I also thought of the Ping Sensor from Parallax but too hard to program with my beginner standards in C and, it used too much power. (I'm more of a Spin and Assembly language person.) I finally looked through my sensors box and found...(...drumroll please...) ...Parallax's Passive Infared Motion Sensor! It was fairly inespensive ($9.99), it could work in the dark, and, I have had experience in programming these!

Step 1: Get The Required Materials.

1 of everything except where noted.

PIR Motion Sensor from Parallax
LED ( Preferably Ultra Bright White. I bought mine along with other colors at Ebay from this seller: http://myworld.ebay.com/led.shop*2010/?_trksid=p4340.l2559

They will compile your own personal mix of colors if you want them to...they will charge more but it is a personalized order. I also found this order of only white LEDs but very cheap.


Many jumper wires

Optoisolator/ optocoupler/ relay

Resistor. Define the value yourself.
Gud project but it can be done without using the arduino!<br>
Of course!<br><br>It can be but since I was entering this in a Arduino competition I used the Arduino. I could have used a transistor and possibly a Darlington transistor. Maybe I will make another one with a transistor...

About This Instructable


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Bio: I love building things and taking pictures. If you want me to build something...I'm open to ideas. My motto? "If you want something ... More »
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