How to reduce the false positive rate of infrared radiation

Infrared detectors are professionally called "beam interception sensing". In addition, it has another name: active infrared detectors. The principle is that infrared rays are emitted by infrared LEDs and focused by spherical lenses. Out, and then received by the optical receiver. Therefore, the general infrared radiation is paired, and an alarm will be issued when the light beam emitted by the transmitting end is interrupted by the object.

The on-beam infrared detector is criticized for being more prone to false alarms than other anti-theft alarm devices. However, this problem that plagues many engineers and users is mostly derived from small details that everyone ignores.

The first small detail is the focus of the infrared beam.

When many engineers have minimized the source of external interference, they still can't completely solve the problem of false positives because they ignore one of the most important keys - accurate focus.

What is "focusing" is to let the infrared beam emitted by the transmitting end be accurately received by the receiving center point. This is like the archery. It is also the middle target, but can the shooting target be the same as the shooting outer ring?

The second one is easy to be disturbed by small animals, such as plants placed on the fence, or cats and dogs climbing the wall, causing frequent false positives, and finally turned off the anti-theft device.

In order to solve this problem, the on-beam infrared detector should not be placed directly on the wall end, but a protruding L-shaped bracket should be placed along the wall to install the device here to form a virtual protective line parallel to the wall. In this way, it is not easy to be falsely reported by the potted plants and the kittens blocking the beam on the wall, and when the thief turns over the wall, the width of the human body will surely interrupt the alarm. This will give you the best of both worlds.

The third is the impact of intermittent environmental factors.

Like the leaves that fall from time to time, the floating flags are the source of interference, and if there are fruit trees nearby, it is easy to have ants, nests, and interference sources.

These problems should be tested to adapt the product itself to the surrounding environment. In addition, different beams have different environments. At present, the common infrared radiation detectors can be divided into single beam, double beam, 4 beam, and 8 beam. In theory, the more the beam, the more careful it can be judged, reducing the false positive rate, but in fact it depends on the actual demand.

For example, a single-beam infrared ray detector is cheaper than a dual-beam, but what many people don't understand is that the single-beam projection distance is suitable for short distances, and the light resistance and water resistance are poor, but the double beam can be done. It is detected at a long distance and has high light resistance and water resistance. If a pair of dual beams are required over a long range of distances, then at least two or more pairs of single beam devices are required. Therefore, when you really choose a product, you must choose the product according to the needs of the prevention area!

More reductions in false positives are not as good as a product with a low false alarm rate. Aurora's ABT infrared detectors use true digital circuits for more stable and reliable performance, and the debug indicators use precise digital circuits. It is more intuitive and convenient to proofread signals during construction. High-power military-grade launch tubes are also used with digital filtering technology to improve the concentration of infrared radiation, that is, to ensure the emission distance and service life of infrared rays. , also makes the detector more accurate and more stable

And the passenger-European infrared detector has a waterproof rating of up to IP65, which is not afraid of bad weather.