Dual Laser Detector Alarm Beam Sensor Indoor 300m Outdoor 60m Infrared Detector 6.7"x3.1"

This review is for a "Dahszhi Dual Laser Detector Alarm Beam Sensor Indoor 300m Outdoor 60m Infrared Detector"This is a reliable alarm that doesn't give false trips and its not tripped by cats, dogs etc. (unless they are over 3 feet tall). The internal NC/NO switch is rated at only a few milliamps so you'll burn it if you try to drive a load directly. A few basic components have to be added for a complete circuit. A relay, transistor or triac, alarm buzzer or equivalent (depending on application) and a power supply at both ends. My installation has the receiver and transmitter about 60 feet apart. The setup isn't hard and tools are provided to simplify it. A small mirror assembly helps with aiming and a signal strength test point (VDC) makes it so you can tell when the beams are properly aligned. The most involved part is running wires.===Update: Had one of these running almost a year now, 24/7 with no problems. I bought a second set that establishes a beam across the entire width of our front yard and rings a door bell. Visitors don't have to press a doorbell button because they trip this beam and it does the same thing. And anyone approaching the carport trips it as well.These units are well sealed from weather and I've found them to be very reliable. I was using one with a 12V 30 milliamp relay coil for a while, but that may be pushing the operational limits so I added a simple transistor circuit to reduce the current through the normally open contacts to about 4 milliamps. A cat was able to trip the doorbell by jumping off the car hood -- through the laser beam, but aside from that, no false alarms. :)I don't see any issue about how well these units are constructed. They are built well for the application. The entire electronics assembly is easy to completely remove from the housing for maintenance if it ever becomes necessary. Very good product.

I have been using these sensors for various purposes for 12 hears. They are excellent. If the alarm is tripped, it has never been a false alarm. Heavy Snow, Heavy rain, falling leaves have never tripped it but it always gets tripped if a person, auto , deer etc passes between the xmitter and receiver.

After I finally got it working it performs well. Instructions are a clear detriment. The alignment mirror device is not clearly explained, and in the end, a useless component. Just align the two unit by eyeball and use a voltmeter to confirm sufficient accuracy. I needed these to alert intrusions by javelinas, coyotes, and donkeys in my Arizona back yard.They are positioned about 100 ft apart and operate correctly. However, I had setup the trial in my garage, about 10 ft apart. Here, I could never get them to function consistently. After hours of messing with settings and connections, I realized that the lenses needed considerable dampening. The darkly tinted housings accomplish this, which became apparent after I covered one pair of lenses with masking tape. I had put the masking tape there so that I could use a laser to assist with alignment. To my surprise, that is when they started to function as desired. I never considered putting the housings on in the trial setup, since I was still dealing with wiring issues and internal adjustment mechanisms. Hard to do with covers installed. Again, this could have been mentioned in the instructions. Seems that not everyone is as persistent as me and simply return them to Amazon out of frustration.

Could not get this to work at all. Would not recommend.

Excelent. Easy to install and set up.

Could not hold the beam I returned it.

looks like the ds detection system electric eye I installed for years. Bring alantern and a chair when installing to calibrate the electric eye. You dontneed a second person if you put the chair directly front of eye and thelantern top of chair looking at other end.

Perfect