Spynet Laser Trip Wire

Product Information

One such innovation is the laser trip wire alarm, which has shown to be extremely effective in detecting and repelling intruders. Detecting the laser can be tricky with a small target like an LDR or an IR receiver, if either end gets bumped. This component is used to trigger the relay latch circuit wired around the planar passivated, very sensitive gate silicon controlled rectifier BT169 (T1). A tripwire is a device triggered by physical movements, you can use it to detect people, animals, cars. Trading in the paranormal community for over 12 years, Infraready have become one of the UK's leading and trusted suppliers of ghost hunting equipment.

The receiver circuit includes an electromagnetic relay to assist the switching process of external electric loads such as floodlights, home alarm systems, etc.My laser pointer (and all of the others I have seen) have a completed circuit when the end cap is on, so I connected the other alligator clip to the bit of metal on the inside of the laser pointer. The LED and resistor should be connected in series between Pin 9 (Light Blue Wire) and GND (Black Wire). One way of getting around this is by using a capacitor, and timing how long it takes to charge up above 1.

It has a selector switch on the side that allows the user to set what key sequence will be “typed” once the system has been tripped. Alternatively, the cloaking augmentation allows Jensen to walk directly through lasers without fear of detection. The photoresistor should have a value in the kilo-Ohms with the light hitting the photoresistor and the low hundreds of Ohms or lower. The red line laser actually triggers a latching switch, that can be connected to any external load/security device such as a loudspeaker alarm, floodlight, or CCTV cameras.Once the LASER beams are cut, the alarm will go off and will not stop until the push button is pressed even though the module detects the LASER again. Connect one of the alligator clips to GND, and the other to pin 4 (or any pin, so that you can control the laser).

Finally, we use a never-ending while True: loop to continually display the current value of the light sensed by the LDR, which ranges from 0 to 1. The Laser Doorway Tripwire is a simple but effective trigger alarm that can be set up in second to provide a means of alert when the pathway to a doorway is broken. I am planning on using a 555 or Arduino Nano to pulse an IR led at 38kHz and I will have another Arduino detecting this with an IR receiver. When the laser beam is interrupted, the light intensity over the LDR decreases, increasing its resistance, this causes the voltage at pin 6 (Threshold) to rise above the reference threshold voltage. When the laser diode shines on the photoresistor, it has a high resistance and the pullup resistor pulls the voltage of the input to a digital high.An LDR (also known as a photocell) is a special type of electrical resistor whose resistance is very high when it’s dark, but reduced when light is shining on it. A photoresistor is a resistor whose values change depending on light shining on the face of the resistor. One day I found an old IR burglar alarm sensor, so I pointed it across my cube opening and concealed it, and connected it to a background application that would quietly play the Star Trek door opening ssshhht sound. We’ll now put it all together so that laser pointer shines at the LDR through the straw, and whenever the beam is broken, the buzzer sounds the alarm. The pullup resistor and voltage source are internal to the MCU (Arduino) in this case and the “button” is our photoresistor.