Project Guidance for Detector Device

Hi Everyone, can i do this thing ? this is an active infrared detector , the detector when triggered will also trigger the
ALARM labeled below, i want to capture that signal and transmit and read it to the arduino , is this possible ? tnx everyone!

You might need a 10k pullup resistor on your digital input pin. Do you have a link for the IR detector ?
It appears to have a relay. It says the PS voltage = 12V. By running on 6V you are probably severely limiting the range. Find a 12V battery to use for that , like a 3S lipo or a 12V lantern battery (rectangular,
hardware store item. You could also double your current battery pack. You need to find out what that alarm output is . Is that a digital signal or what ? You need to find that out before connecting it to the arduino, especially if it was running on 12V.

this is the only link i got sir ..

http://csst-longhorn.07551.net/en/productshow.asp?sid=31&ssid=194&sssid=221

and yes sir i can take it from the power supply matter ,,
but i'm having a difficulty knowing what the alarm output is ,,, i'm aware that it may cause damage to the digital pins of arduino if i mistakenly connected it to the wrong pin,, do you have ideas how can i determine that signal sir ??

by the way sir , why do i have to use a pullup resistor ? when and what devices do i have to use pullups ?

Actually I am still not sure if you need a pullup resistor because I am not sure what the alarm output is.
If I were you I would get a multimeter and do a continuity check to the relay on the board to see if the Alarm output pin is connected to one of the relay contacts. My guess is that this is a security alarm module and the way those usually work is the relay is engergized when motion is detected while the alarm is ARMED. The relay is an SPST (Single Pole Single Throw) relay and the two Alarm output pins have continuity when the relay turns on and are OPEN (no continuity) when the relay is off. They are designed to be used by connecting power to a siren or horn. To interface with arduino treat the two pins like a button switch , with one pulled up to 5V and the other to ground. When no motion, signal is HIGH. When Alarm out is TRUE, signal is LOW.