Looking for a movement sensor in the form of a beam, similar

[nicom]

Hi Everyone,

I am looking for a sensor that I can use to trigger a sound every time it gets tripped. I have a PIR sensor and the radius is to wide. I hate to use movies as an example but I just want a beam or something similar to the heist movies where technically you could step over it and not set it off.

Do those exist?

I think the IR Distance Sensor(http://www.adafruit.com/products/164) could work if I code it to look for changes in distance. I also found the Ultra Sonic Range Finders which seem like an option but I am new to electronics (and loving it thanks to adafruit and the tutorials) so I would love advice from the community.

Please let me know if you have any questions about my request.

Thanks!

Nico

[adafruit_support_bill]

You can narrow the field of view of the PIR by putting a shroud around it (a toilet-paper tube works).
Laser trip wires are certainly possible too. Here is a self-calibrating one: http://keithkay.com/2013/03/03/arduino- ... trip-wire/

[nicom]

Cool thanks! That trip wire tutorial looks awesome. I will try that out, but in the meantime give the paper towel roll a try.

Thanks again,
Nico