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using 7400 I C light detector
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MYSURU-
DIGITAL PROJECT [EC3C02] –3 rd^ Semester
Synopsis On
Under the guidance of:
Nandhini S P
Asst.Professor, Dept. of ECE.
Submitted By:
Suraj U Mogali : 4NI18EC
Prajwal S D : 4NI18EC
Simple light detector is a device that uses 74LS00 NAND gate chip and photo resistor to effectively detect light.
The circuit has 9V supply voltage that drives the 74LS00 NAND gate chip, which is connected to pin 14 and pin 7 respectively, connected to the ground. The voltage divider circuit is composed of a photo resistor and a 6.8kΩ fixed resistor where voltage is distributed across the components in direct proportion to the amount of resistance each component offers. The more resistance a component offers in relation to the other, the more voltage that will fall across that component. When a photo resistor is exposed to darkness, it has very high resistance, in the order of a few Mega ohms (MΩ). With high resistance, most of the voltage from the power supply feeding the voltage divider circuit falls across the photo resistor with very little voltage falling across the 6.8kΩ fixed resistor. Thus, when connected to the inputs of NAND gate, with voltage so high, the NAND gate will essentially interpret the voltage divider as HIGH or logic 1. When the voltage feeding the inputs of a NAND gate are greater than half of the power supply voltage, it will interpret it as a HIGH value. When a photo resistor is exposed to bright light, its resistance drops dramatically and significantly turns ON the LED.
This project can be integrated to security or safety devices such as burglar alarm that constantly senses a beam of light where any changes in light cause it to alarm. Moreover, it can be used to motion sensing devices as well as to computers, wireless phones and television to automatically control the brightness of a screen especially in low-light or high light situations.
In this project, we will build a light detector circuit using a NAND gate chip.
A light detector circuit is a circuit that can detect light.
When a bright light shines on the circuit, such as from a flashlight, we will make it so that a buzzer turns on.
The circuit is very basic. The component that will allow us to detect light is a photo resistor. We will use a photo resistor’s light-sensing ability to detect whether the circuit is exposed to darkness or bright light. How this works is that a photo resistor’s resistance changes in proportion to the amount of light it is exposed to. In darkness, it has very high resistance. In bright light, its resistance drops dramatically. If placed in a voltage divider circuit with a fixed resistor, we can exploit this resistance-altering behaviour so that when connected to a NAND gate, we can produce a logic HIGH output when the photo resistor is exposed to bright light and a logic LOW output when the photo resistor is exposed to darkness. All of this will be explained in detail below how exactly this works. But realize that a photo resistor’s resistance-changing ability allows us to distinctly know whether it is exposed to darkness or bright light. Knowing this, we can effectively build a light detector circuit.
The schematic diagram of the light detector using a NAND gate chip is shown below.
First and foremost, we must give power to the NAND gate chip. We will feed it 5V of power, so we give +5V to pin 14 and we connect pin 7 to GND. This establishes power to the chip.
The circuit is very basic. The component that allows us to detect light is a photo resistor. We set up a voltage divider circuit composed of a photo resistor and a 6.8KΩ fixed resistor. In a voltage divider circuit, voltage is distributed across the components in direct proportion to the amount of resistance each component
Components :
The solar powered LED streetlight with auto intensity control the electric charge and intensity of lights.This project can be enhanced by using
the timer based products and photo sensor product.To improve lightning we use LED panel
This project consists of all the information and the components required. For further information visit the link mentioned below
https://www.electronicshub.org/light-detector-using-ldr/
https://circuitdigest.com/electronic-circuits/nand-gate-circuit-diagram
