Sensors for lighting controls are either photoelectric sensing or presence detectors. Photoelectric sensors are normally set to switch lighting on at dusk and off at dawn. Adjustments can be made to change response to higher or lower levels. Built-in time delay helps to eliminate nuisance switching in response to sources other than natural ambient
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light, or passing shadows. Photoelectric sensors are often combined with timers to provide a more efficient light control. Figure 12 shows such a control arrangement. Contacts on both photoelectric switch and the timer must close to cause the multi-pole lighting contactor to switch on the lights. Opening either set of contacts will open the lighting contactor, thus turning off the lights. A typical application would be an industrial parking lot where lighting is required only Monday through Friday evenings, and is turned on at dusk and shut off at midnight. The two-wire control may be a separate electromagnetic control relay or a built-in control module as shown. A variety of presence detectors or occupancy sensors have been recently developed. These detectors automatically activate the lighting controls. They are designed to turn lights on upon sensing heat or motion caused by human occupancy within a defined space and turn them off at some preset time after the last person leaves. PART II. Todays industrial computer and programmable controller (PLC) based control systems are sophisticated versions of electronic timers. The heart of such a system is an industrial computer and/or PLC-based controller that holds in memory a series of on-off instructions to the lighting circuits throughout a building. They can provide minute-by-minute control of an entire lighting scheme according to a user-determined schedule, with pulse...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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