DEI 509U ultrasonic sensor

DEI is a multi-national company now. Since taking over many smaller Asian companies, its product line is full of the same things, and some items that are made for those markets have shown more interest in the types of equipement you have listed. You will note that the current fad of 2 way paging and those alarms with toy like screens have been sold and marketed in the Asian markets 3 years before it ever landed in the America's. There are alot of cutting edge technologies which we never see. There are even more useless toy like equipment that we always do. It comes down to what they feel will sell, or based on the *There is a sucker* born everyday theory. Regardless of that fact, there a few companies that sell similar ultra-sonic sensors, which can be incorporated into your current system. I hope you understand the theory and practice of such sensors. Currently the most stable and surprising fully functional sensor is made from Sherwood. Who knew that a stereo company could make something like that? ======================================================= A ultrasonic proximity sensors which allows for alternate transmission and reception of sound waves. The ultrasonic transducer emits a number of sonic waves which are reflected by an object, back to the ultrasonic transducer. After emission of the sound waves, the ultrasonic sensor will switch over to receive mode. The time elapsed between emitting and receiving is proportional to the distance of the object from the sensor. Ultrasonic proximity sensors enable the detection of different objects - irrespective of color and transparency. Regards EVIL Teken . . .

The unit that Sherwood designed and sold was in fact a Infrasonic sensor model IFS-1000. I apologise for the mistake. Below I will discribe to you the basic principle of each. Utrasonic = Measures sound waves toward the target and measures the time it takes to for the pulses to bounce back. The time it takes for the echo to return to the sensor is directly proportional to the distance and height of the object because sound has a constant velocity.     Infrasonic = Measures air pressure waves. Infrasonic is basicly a barometric sensor. It is considered volumetric sensor which doesn't rely on movement or mass displacement. This sort of sytem requires dual sensor, one sensor mounted outside the vehicle (concealed under the bonnet but still in 'open air') and a second sensor mounted inside the vehicle under the dash. These two sensors constantly calibrate and compare air pressure outside with the air pressure inside the vehicle's cabin. A drop in air pressure inside the vehicle (caused by door opening, boot opening, window breaking, etc.) causes the alarm to trigger BUT an environmental disturbance outside the vehicle (ie strong winds, passing vehicles rocking the car, storms, etc.) will not cause the alarm to trigger. Similarly, if a direct physical impact is made to the exterior of the vehicle's panels, glass, etc. it causes a 'ripple' effect disturbance that will trigger the alarm. However, an indirect motion (trucks passing, wind, etc) move the vehicle as a whole and will not trigger the alarm I hope that give you a small insight of both types of sensors. Regards EVIL Teken . . .

Where can I purchase one of these sensors at?

The 509U is sold in the US. I installed one about 2 months ago in a trailer for my boss. I don't know of any websites selling one though.