Automatic light ON-OFF using LDR.

LDR is a Light Dependent Resistor, when light falls on it, its resistance decreases to few hundred of Ohms and when there is dark then it offers resistance of value near about 100kOhms.

This post is about how a LDR sensor can be used to build an automatic light control circuit, by using LDR, transistor BC557, 100k pot, a resistorr and 9V battery a circuit is built on zero PCB.

When there is dark in the room then automatically the LED is ON and when there is brightness in the room then the LED is OFF. 

The video shows the implemented and tested board.

Electronics devices Fundamentals

When you are going to start learning the subject Electronics devices, At first sight you need to understand some key concepts and definitions which are explained below.

Matter:  Matter is defined as anything that has weight and can occupy space.

e.g. our own body, air, water etc. and matter can be found in any one of the three states: Solid, Liquid and Gaseous.

Element: A substance which can not be reduced to a simpler substance by chemical reaction.

e.g. copper, gold, silver.

Compound: When two or more elements are combined chemically then the new substance formed is called as compound. Compound can be separated by chemical but not physical means.

e.g. salt, water.

Atom: An Atom is the smallest individual particle of an element which retains the characteristics of that element. These atoms of each elements are made up of Electrons, Protons and Neutrons.

Electron is having small negative charge of electricity. Proton has positive charge of electricity which is equal and opposite to the charge of Electron. Neutron has no electric charge.

Electrons, Protons and Neutrons are arranged like a solar system. Protons and Neutrons are at the center and they form a heavy nucleus having positive charge and Electrons revolve around them.

Atomic Number: The number of protons in the nucleus gives the atomic number. 

Below figure shows the atomic structure of Silicon atom.

From above fig. atomic number of Silicon is 14. In this fig. shown the black circles are called as shells. The number of electrons required to fill the shells is given by Pauli's Exclusion Principle it states that each shell will contain maximum of 2(n^2) number of electrons where n is shell number starting from 1. By this principle first shell consist of 2(1^2) that is max 2 electrons, second shell consist of 2(2^2) that is max 8 electrons, third shell will consist of max 2(3^2) that is 18 electrons and so on. 

Valence: The number of electrons in the outermost shell gives the Valence of that atom. For this reason the outermost shell of an atom is called as Valence shell and the electrons in this shell are called as valence electrons. The valence shell can either gain or lose electrons depending upon the number of electrons.

Ionization: When an atom gains or lose electrons in this process it is said to Ionized. When an atom gains electrons then it becomes more negative and is called Negative ION. When an atom loses electrons then it will be having less number of electrons than previous and it becomes a Positive ION.

Touch Switch using BJT

This is a simple touch switch circuit built using transistor. In this circuit when a person touches the touch pad provided (or you can have simple wire instead of touch pad) at the base of the NPN transistor and also to the positive of 5V battery then his/her skin acts as a resistor and this closes the circuit and at the same time the transistor turns on and hence the LED connected there glows.
Here I have given Proteus demonstration of the same.
When no one touches the pad LED is not ON is shown below.

When someone touches the pad then the LED glows and is shown below.

Motor rotation direction control circuit.

Simple Motor direction control using Relay

Below circuitry shown is the simple circuitry for controlling the rotation direction of motor using relay driver and a push button to switch the relay driver. This has been implemented in proteus and tested successfully.

Go through the same and have fun with it.

Components used:

Resistor 1k

Relay 12v

Simple DC motor

Push button

Transistor NPN BC547

Diode & 

Power supply and batteries.

Smart Parking Project

Smart Parking Management System

Here I'm showing a simple Parking Management project which is smart one.

In the below figure shown it is implemented on proteus and simulated successfully.There is a LCD display located outside the parking system.It shows the number of lots available and which lots are available.Also iwhichever lots are available the lights at that lot will glow and whenever vehicle is parked light will switch off automatically.

The code for the smae is given below you can connect your LEDs of respective lots to pin no.22 to 29

VHDL Codes

VHDL CODES     

1.   4:1 MUX USING IF ELSE STATEMENT

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.STD_LOGIC_ARITH.ALL;

use IEEE.STD_LOGIC_UNSIGNED.ALL;

 

---- Uncomment the following library declaration if instantiating

---- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

 entity MUX41 is

   Port ( I : in  STD_LOGIC_VECTOR (03 downto 0);

          SEL : in  STD_LOGIC_VECTOR (01 downto 0);

          Y : out  STD_LOGIC);

end MUX41;

architecture Behavioral of MUX41 is

begin

PROCESS (I,SEL)

BEGIN

IF(SEL="00")THEN

Y<=I(0);

ELSIF(SEL="01")THEN

Y<=I(1);

ELSIF(SEL="10")THEN

Y<=I(2);

ELSE

Y<=I(3);

END IF;

END PROCESS;

end Behavioral;

 

2.         4:1 MUX USING CASE STATEMENT 

 

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.STD_LOGIC_ARITH.ALL;

use IEEE.STD_LOGIC_UNSIGNED.ALL;

 

---- Uncomment the following library declaration if instantiating

---- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

entity mux41 is

   Port ( I0 : in  STD_LOGIC;

          I1 : in  STD_LOGIC;

          I2 : in  STD_LOGIC;

          I3 : in  STD_LOGIC;

          SEL : in  STD_LOGIC_VECTOR (01 downto 0);

          Y : out  STD_LOGIC);

end mux41;

architecture Behavioral of mux41 is

begin

PROCESS (I0,I1,I2,I3,SEL)

BEGIN

CASE SEL IS

WHEN "00"=>Y<=I0;

WHEN "01"=>Y<=I1;

WHEN "10"=>Y<=I2;

WHEN OTHERS=>Y<=I3;

END CASE;

END PROCESS;

end Behavioral;

3.            3:8 DECODER USING CASE STATEMENT

library IEEE;

use IEEE.STD_LOGIC_1164.ALL;

use IEEE.STD_LOGIC_ARITH.ALL;

use IEEE.STD_LOGIC_UNSIGNED.ALL;

---- Uncomment the following library declaration if instantiating

---- any Xilinx primitives in this code.

--library UNISIM;

--use UNISIM.VComponents.all;

entity dec38 is

   Port ( a : in  STD_LOGIC;

          b : in  STD_LOGIC;

          c : in  STD_LOGIC;

          d : out  STD_LOGIC_VECTOR (07 downto 0));

end dec38;

architecture Behavioral of dec38 is

signal enw:std_logic_vector(2 downto 0);

begin

enw<=a & b & c;

process(enw)

begin

case enw is

when"000"=>d<="00000001";

when"001"=>d<="00000010";

when"010"=>d<="00000100";

when"011"=>d<="00001000";

when"100"=>d<="00010000";

when"101"=>d<="00100000";

when"110"=>d<="01000000";

when"111"=>d<="10000000";

when others=>d<="00000000";

end case;

 

 

 

 

 

 

Learn VHDL programming ONLINE!!!

      To learn VHDL programming just go through these websites ...Have fun

You will get the programs too.  

1.http://esd.cs.ucr.edu/labs/tutorial/

2.http://www.asic-world.com/vhdl/tutorial.html

3.http://users.ece.gatech.edu/sudha/book/starters-guide/