Imagine that you earned yourself before dark in the workshop, which is in one of the outbuildings on the opposite edge of the house edge of the site. The switchboard, from where the lights come on all over the territory, is in the house, that is, it will have to go there literally to the touch. But if in each lamp or even in the general chain there was a photo sensor for street lighting, with the onset of twilight, along all the tracks, the light bulbs would have flashed, having gone out only with the advent of dawn. But what kind of sensor is it?
Externally, it is very similar to the LED, that is, the same transparent case( in some cases there is only a transparent window from the end) and two outputs - a collector and an emitter. Such a sensor is tuned to a certain light wave from the entire available spectrum, that is, it can be activated by infrared radiation or ultraviolet. How does this happen? As the illumination increases, the resistan
As already mentioned, phototransistors can be installed in either a lantern, or only one for the entire circuit. In which cases what is preferable? For example, along the site, the tracks run radially from the house, along each of which the supports with economical lamps in plafonds were lined up. For each circuit a separate switch, and on the first lamp - a sensor. The breaker constantly closes the circuit, but the current does not come due to the high resistance in the phototransistor. As soon as it gets dark, the resistance drops, the circuit closes completely, and all the lanterns light up at once.
If you do not have a cable connection of lamps with a single power source, and each of them has an individual - a solar battery, it is necessary that the street lighting sensor be installed on all lanterns without exception. Of course, in this case, simultaneous inclusion of lamps is made difficult by the fact that one of the phototransistors falls shadow from the tree, the other constantly in bright light. In addition, if the optics of the sensor are dusted, this will greatly worsen its operation, resulting in an imitation of the eternal twilight .
Even if you have solar-powered lights, the life of lamps and batteries is quite limited, within a few thousand hours. Therefore, if you do not need to save electricity, the safety of lighting devices and batteries should be taken care of. Using a photosensor, you will, nevertheless, cause the lights to burn all night. If you use the timer and the light on the tracks closer to the middle of the night, it will cause some inconvenience if you suddenly need to go somewhere later. In such cases traffic sensors for street lighting are invaluable.
Photocells reacting to movement, rather than a thermal spectrum that exceeds the ambient temperature by 5 or more degrees, can also trigger when the trees are swaying in the wind.
There are two types: with a photocell catching a beam aimed at it, the interruption of which will mean the signal to the automation, and also with tracking the infrared range in the environment. It is logical that the first are installed in the transmitter-receiver pair, so that the beam emanating from the first is picked up by the second. Infrared sensors that respond to movement can be anywhere, provided they have a sufficient sector of view, which can be calculated for 180 or 360 degrees .It is very convenient to move around the site when, passing by the flashlight, when you approach it, you see how the next one turns on, and a few more steps behind your back the first goes out.