Intro: Automatic Dark Detector
I made a project on this platform and It's not that much effective. So this project is all about the some minor upgrade to increase the effectiveness. If you are following me then you know that what I am talking about.
Or If you seen my projects for the first time then just stick with this project.
So lets start....
Step 1: Parts Required
First Step in a project is planning and gathering materials.
So now lets gather the items to make the project.
Electronic components required:-
10K resistors - 1 nos
BC548 NPN Transistor - 1nos
LED's - 4 nos
LDR (400Ohm or 1000lux) - 1nos
Prototyping PCB board - 1 nos
5v DC Power Source
Step 2: What Is LDR?
A photoresistor (or light-dependent resistor, LDR, or photocell) is a light-controlled variable resistor. The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photoresistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits.
A photoresistor is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can substantially differ among dissimilar devices. Moreover, unique photoresistors may react substantially differently to photons within certain wavelength bands.
Step 3: Schematic for Automatic Dark Detector
Follow the circuit diagram and you will be able to make this project. Its a good start for beginners. And by This circuit you can lots of another things. In my future projects I will show you how.
The circuit is very simple and very easy to make. You just have to connect one terminal of 10K Ohm resistor to 5V Dc supply and another terminal to Base of NPN transistor, similarly connect one terminal of LDR to base of NPN and another terminal to the emitter of NPN transistor and then connect emitter terminal to GND.And add some LED's in parallel and +ve terminal to 5V DC supply and -ve terminal to collector of NPN transistor.
Here I am attaching PDF file if you need PCB Layout and circuit diagram on paper. If you are interested in PCB etching and need Printed Circuit.
Step 4: Watch This Video for Demo Purpose
Hope you like the video and like this project and I am waiting to see yours.