need help with passive infared motion sensor

twistedamd

hi everyone
·im new so let the onslaught begin..im trying to make a motion detector box. i have the motion sensor, toggle switch, siren, 9 volt battery hook up and a led . I hooked everything up as i thought it would go but no matter what i try its just the siren and led going off. can someone please tell me what i need or what i can do to get this working?
thanks

Mike Green

You didn't say what kind of motion sensor you're using. The ones that Parallax sells need a microcontroller like the Stamps to control other things like an LED or a siren. A siren needs some kind of switching transistor as well because of the power needs. There are examples of this in the Parallax documentation. You could use a PIR sensor with a switching transistor to operate a siren and/or LED. You may have damaged your motion sensor by trying to run a siren with it. In any event, you need to provide complete information about what you're trying to do and what you've done so far if you want anything other than very general advice. If you're not using Parallax devices, you'll need to provide information about what you're actually using.

twistedamd

it is a parallax sensor. I am just trying to make my own inexpensive motion detector box with sound and led lights. is there any other motion sensors out there that i wouldnt need a microcontroller? any help on this would be very helpfull.. thanks for your time

Mike Green

The Parallax PIR sensor can be connected through a switching transistor to things like a siren or LED. Download the Nuts and Volts Column #6 by going to the main Parallax webpage, selecting the Resources tab and clicking on Nuts and Volts Columns to go to the index. The last page of the column shows a switching transistor connected to a Stamp. You can connect it to the PIR sensor's signal output the same way.

The siren and/or LED will only turn on when there's motion being detected (if the sensor's jumper is connected for retriggering ... see the sensor's documentation). If you want some other type of action like a long siren or a siren until disarmed or something like that, you'll need to use a microcontroller to provide that sort of action.

Post Edited (Mike Green) : 2/8/2009 10:35:24 PM GMT

twistedamd

thanks for that ! ok i found some switching transistors at radio shack they have 3 pins on them can you please give me the basic hook up for my situation? thanks for your help!

SRLM

Ah Ha! I've been waiting for someone to ask that question. See the link below.

http://forums.parallax.com/showthread.php?p=775638

Mike Green

Download the article I mentioned (here: www.parallax.com/Portals/0/Downloads/docs/cols/nv/vol1/col/nv6.pdf) and look at the last page. You'll need a 1N4002 or 1N4001 diode that you can get from RadioShack and a 2N2222 or 2N2222A transistor or equivalent (also from RadioShack) and hook them up as shown, but to the PIR sensor output pin rather than a Stamp pin. You'll need a resistor like the 390 Ohm one shown. If they don't have 390 Ohms, you can use 330 Ohms in an 1/8 Watt or 1/4 Watt size. The RadioShack package will show you how to identify which pin is which on the transistor and diode. The diode lead with the bar or line on the package is the cathode, shown on the schematic with a bar (instead of the arrowhead end which is the anode). The transistor lead with the arrowhead is the emitter (E). The lead that goes to the Stamp or PIR sensor is the base (B) and the lead that goes to the siren or relay or LED is the collector (C). Most LEDs require a resistor in series with them to limit the current though the LED. For a 5V power source, a 330 Ohm resistor works well.

twistedamd

wow thanks for that i will try that tommorrow! so i can hook the siren and led to collector c at the same time?sorry for the newb ?s i am trying to learn lol.. thanks!