LED Chasing (Blinking) Circuit using Microcontroller: Electronics Project

Working Principle

This project turns on the LEDs connected to port 1 of the microcontroller in sequence, resulting in chasing LEDs effect. The data is displayed with a one-second delay between each output pattern. The following figure shows the output pattern of LEDs. (There are only 8LEDs).

1

Components

  • AT89C2051 microcontroller
  • Capacitors: 10uF, 30pF, 30pF.
  • Resistors: R2=100O…..(8) and one 8.2KO
  • Crystal oscillator: 12MHz
  • LEDs: 8

Circuit diagram

The following figure shows the circuit diagram of LED chasing project. For better appearance, you can also arrange these LEDs in circular or any geometrical shape with different colors for colorful output.

LED chasing circuit diagram
LED chasing circuit diagram

LED chasing circuit using AT89C2051 microcontroller
LED chasing circuit diagram

Program description

The program is required to load a 1 into the top (or bottom) bit of a variable and then shift the data right (or left) by one digit and display on the LEDs. A delay is required between each out to see the effect of chasing.

Download

Click here to download .C and .HEX file for this project

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LED Dice using Microcontroller (8051): Electronics Project

In this project, we are going to build a LED Dice using microcontroller. We have already seen many microcontroller project, you can check all the previous project here. This project is used to simulate dice, which displays a random number from 1 to 6 by using 6 LEDs connected to port 1 of the microcontroller. Pin no 2 (or bit 0 of port 3 (P3.0)) is used as the input and a push-button switch is connected to this pin. Every time, when we press this switch, a new number is displayed.

Circuit Diagram: LED Dice using Microcontroller

The circuit diagram for LED Dice using microcontroller project is shown in the figure below.

LED dice using AT89C2051 microcontroller Electronics mini project
LED dice using microcontroller

LED dice using AT89C2051 microcontroller
LED dice using AT89C2051 microcontroller

LED dice using AT89C2051 microcontroller
LED dice using AT89C2051 microcontroller

Bit 0 of port 3 is generally held at logic HIGH with pull-up resistor R3=100K. when switch S1 is pressed, bit 0 of port 3 moves to logic LOW and is detected by the microcontroller. As shown in circuit diagram all the seven LEDs are so mounted that they will show dots for different numbers as in real dice.

The different patterns for different numbers are shown below:

LED dice using microcontroller
LED dice using microcontroller

Program Description

A random dice number is obtained during scanning of the push-button switch as follows. The program scans the push-button switch continuously. If the switch is not pressed (i.e. at logic HIGH), a number is incremented between 1 and 6. Whether the push-button is pressed, the current value of the number is read and this value is used as the new dice number. Since the switch is pressed by the user in random, the numbers generated are also random numbers from 1 to 6. The new random number is displayed on the seven LEDs appropriately. After about 2 seconds delay, all LEDs are turned off and the above process is repeated forever.

Download

Click here to download .C and .HEX file for this project.

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How to make DTMF Decoder: Electronics Project

Circuit diagram of DTMF decoder

Photo1904

Components

1) Breadboard.

2

2) IC 7805 and IC MT8870 (DTMF IC):

3

2) 9V battery:

4

3) four small LED:

5

Capacitors: 1) 0.1uF 2) 22pF 3) 22oF 4) 10uF

6

connecting wires and cutter:

7

Resistors: 100K, 100K, 330K.

8

Crystal Oscillator (KDS 3.5795)  i.e. 3.57MHz

9

Cellphone connector (If possible use NOKIA):

10

1) Step 1:  Insert the DTMF IC (MT8870) in the breadboard.

11

2) Step 2: Ground pin no 5, 6 and 9.

12

3) Step 3: Now connect the four LED’s to pin no 11, 12, 13, 14 with respect to ground.

13

4) Step 4: Connect two 22pF capacitors to pin no 7 and 8 with respect to ground (Don’t worry it has no polarity)

14

5) Step 5: Connect a crystal oscillator to pin no 7 and 8.

15

6) Step 6: Short pin no 1 and 4.

16

7) Step 7: Insert IC 7805 anywhere on the breadboard.

17

8) Step 8: 330K resistor between pin no 16 and 17.

18 19

9) Step 9: Connect 0.1uF capacitor to pin 17 with respect to 5V.

20

10) Step 10: Connect pin 10 and 18 to 5V

21

11) Step 11: 100K resistor between pin 2 and 3.

22

12) Step 12: Connect one pin of 100K resistor to pin 2 and leave other for next step.

23

13) Step 13: Connect negative end of 10uF (50V) capacitor to another end of 100K resistor and leave +ve terminal for next step.

24

14) Step 14: Connect a mobile headphone jack (+ve) to the positive terminal of capacitor and other terminal grounded.

25

15) Step 15: Make proper grounding by connecting wire.

26

16) Step 16: Connect the 9V battery to 7805 IC. Middle terminal to ground.

27

17) Step 17: 5V output given by 7805IC is connected to uppermost row.

28

18) Connect your mobile to the audio jack.

29

19) Press any key on Keypad you will see corresponding BINARY number of that digit. Please make sure that your keypad tones are ON ( To make keypad tones ON go to Settings>Tones>Keypad tones>ON)

30Thank you.

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Watch YouTube video for this project.

https://www.youtube.com/watch?v=OF3SfGyvgbg

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Automatic Street Light Circuit Diagram

Hi friends, today we are going to make a four-way traffic light controller using a PIC16F84A microcontroller (Automatic Street Light). In this project, we will operate three LEDs (RED, YELLOW, and GREEN) according to the traffic rules.

  • Illumination of the green light allows traffic to proceed in the direction denoted.
  • Illumination of the yellow light denoting, if safe to do so, prepare to stop short of the intersection.
  • Illumination of the red signal prohibits any traffic from proceeding.

Four-way traffic controller using PIC16F84A microcontroller
Four-way traffic controller using PIC16F84A microcontroller
Four-way traffic controller using PIC16F84A microcontroller

Components:

  1. Four set of Red-Green-Blue LEDs
  2. PIC16F84A microcontroller
  3. 22uF capacitor – 2 no.
  4. Crystal oscillator 4MHz
  5. 10KO resistor, 330O resistors
  6. 5V battery

Automatic Street Light Circuit:

  1. In this project, we are going to operate (control) a four-way traffic light signal using PIC16F84A microcontroller. The first thing we have to do is, simply connect four set of Red-Green-Yellow LEDs to respective pins of  PIC16F84A microcontroller as shown in circuit diagram. (you can also use separate LEDs just connect all common terminals (negative) to ground with 330O resistor in series with each LED).
  2. 5V supply to the pin number 14.
  3. Ground pin number 5.
  4. Connect two 22uF capacitors in parallel with two terminals of the crystal oscillator.
  5. Make all the remaining connection as shown in the figure.

Download

Click here to download Automatic Street Light .C and .HEX files for this project

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Automatic Plant Watering System Mini Project

This circuit i.e. water watching in flower-pot or Automatic Plant Watering System project is intended to some signal when the plant needs water. Automatic Plant Watering System circuit will glow a LED when the ground of any plant (or flower-pot) becomes too dry and when there is some conductivity between probes which are inserted into that ground the LED will automatically turn off. Adjusting R2 will allow the user to adapt the sensitivity of the circuit for different grounds, pots, and probe types.

Components

  • R1, R4: 470K 1/4W Resistors
  • R2: 47K 1/2W Trimmer Cermet or Carbon
  • R3: 100K 1/4W Resistor
  • R5: 3K3 1/4W Resistor
  • R6: 15K 1/4W Resistor
  • R7: 100R 1/4W Resistor
  • C1: 1nF 63V Polyester Capacitor
  • C2: 330nF 63V Polyester Capacitor
  • C3,C4: 10µF 25V Electrolytic Capacitors
  • D1: 1N4148 75V 150mA Diode
  • D2: 5mm. Red LED
  • IC1: 4093 Quad 2 input Schmitt NAND Gate IC
  • Q1: BC557 45V 100mA PNP Transistor
  • P1, P2: Probes (See Notes)
  • B1: 3V Battery (2xAA, N or AAA 1.5V Cells in series)

Automatic Plant Watering System Circuit

Plant watering indicator circuit diagram
Plant watering indicator circuit diagram

Automatic Plant Watering System Working

The circuit operation of water watching indicator can be explained as follows: IC1A and related components R1 and C1 form a 2 KHz square wave oscillator feeding one gate input of IC1B through the voltage divider R2/R3 made variable by adjusting the Trimmer R2. If the resistance across the probes is low (as when there is a sufficient amount of water into the pot) C2 diverts the square wave to ground, IC1B is blocked and its output will go steady height. IC1C inverts the high status to low, thus keeping IC1D blocked: the LED is off.

When the ground in the flower-pot is becoming too dry the resistance across the probes will increase (and there will be no conductivity between two ends of probes) and C2 will be no longer able to divert the square wave to ground. Therefore, IC1B output begins to transfer the 2 kHz signal to IC1C which, in turn, passes it to the oscillator built around IC1D. No longer disabled by a low level on its input, the IC1D oscillator slowly pulses Q1 base low causing the LED to flash, signaling the necessity to water the plant. The short low pulse driving the base of Q1 is actually a burst of 2kHz pulses and therefore the LED flickers about 2,000 times per second – appearing to the human eye as if the LED was steadily on for the entire duration of the pulse.

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Knight Rider Circuit Diagram Using Microcontroller

Hi friends, today I am going to make my first microcontroller project using PIC16F84A microcontroller. I prefer  PIC16F84A microcontroller because it is quite simple to learn the basics of microcontroller family. PIC16F84A is the best microcontroller for beginners because it has following characteristics:

  • Only 35 single word instructions to learn
  • All instructions single-cycle except for program branches which are two-cycle
  • Operating speed: DC – 20 MHz clock input DC – 200 ns instruction cycle
  • 1024 words of program memory
  • 68 bytes of Data RAM
  • 64 bytes of Data EEPROM
  • 14-bit wide instruction words
  • 8-bit wide data bytes
  • 15 Special Function Hardware registers
  • Eight-level deep hardware stack
  • Direct, indirect and relative addressing modes
  • Four interrupt sources: – External RB0/INT pin – TMR0 timer overflow – PORTB<7:4> interrupt-on-change – Data EEPROM write complete
  • Schematic design of knight-rider with the PIC16F84A microcontroller:

Many circuits on the Internet are built with a CD4017 counter IC. I myself chose to use a microcontroller for this job: the PIC16F84A. A microcontroller increases the complexity but it allows you to build a very flexible light computer. The circuit can be kept very small, this was a requirement for this circuit.

Knight Rider Circuit Diagram

knight rider circuit using PIC 16F84AP
knight rider circuit using PIC 16F84AP

The circuit can be powered by a DC voltage between 7 … 12 V. I used a 7805 regulator to create a stable 5 VDC voltage. If you want to keep the circuit very small you could use a zener diode for the stabilization. The microcontroller is oscillated by an external RC oscillator. The capacitor was left away. This can be done but it decreases the stability of the frequency. The resistor has a value of 10k. The microcontroller drives LEDs through output ports RB0 … RB7.. During the execution of a knight rider effect, there are always 2 LEDs active at a time. I did some measurements on the circuit and the LEDs are active for a period of 0.14 seconds. To change the speed you can simply change the value of resistor R1. You could also add a capacitor between OSC1 and the GND.

Download

Here you can download the .asm and .hex code

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Fastest Finger First Electronic Project without using Microcontroller

Now a days quiz-type game shows are increasingly becoming popular on television. In such quiz games, fastest finger first indicators (FFFIs) are used to test the contestant’s reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button.

Fastest Finger First Project

The fastest finger first circuit diagram presented here determines as to which of the four contestants first pressed the button and locks out the remaining three entries of the other three members. Simultaneously, an audio alarm (buzzer) and the correct decimal number display of the corresponding contestant are activated.

Fastest finger first
Fastest finger first

Components used

  1. Resistors: 1KO, 330O, 100KO, 10O, 10KO
  2. Ceramic Capacitors: 0.033uF, 0.01uF, 0.047uF
    Electrolytic Capacitors: 47uF (35V)
  3. Miscellaneous: Common anode seven segment LED display
  4. S1-S5: Pushbutton (Switches), Speaker (8O, 1W)
  5. Integrated circuits:
    IC 7805     ….voltage regulator
    IC 74LS75 …. 4-bit bistable latch
    IC 74LS20 …. Dual 4 input NAND gate
    IC 74LS147 …. 9 lines to 4 lines priority encoder
    IC 74LS04 …. HEX inverter
    IC 74LS47 …. BCD to seven segment decoder
    IC NE555 …. Timer

Working of Fastest Finger First Indicator:

When a contestant presses his switch, the corresponding output of latch IC2 (7475) changes its logic state from 1 to 0. The combinational circuitry comprising dual 4-input NAND gates of IC3 (7420) locks out subsequent entries by producing the corresponding appropriate latch-disable signal. Priority encoder IC4 (74147) encodes the active-low input corresponding audio oscillator. binary coded decimal (BCD) number output. The outputs of IC4 after inversion by inverter gates inside hex inverter 74LS04 (IC5) are coupled to BCD to-7-segment decoder/display driver IC6 (7447). The output of IC6 drives common anode 7-segment LED display (DIS.1, FND507 or LT542). The audio alarm generator comprises clock oscillator IC7 (555), whose output drives a loudspeaker.

The oscillator frequency can be varied with the help of preset VR1. Logic 0 state at one of the outputs of IC2 produces logic 1 input condition at pin 4 of IC7, the audio oscillator IC7 needs +12V DC supply for sufficient alarm level. The remaining circuit operates on regulated +5V DC supply, which is obtained using IC1 (7805). Once the organizer identifies the contestant who pressed the switch first, he disables the audio alarm and at the same time forces the digital display to ‘0’ by pressing reset pushbutton S5. With a slight modification, this circuit can accommodate more than four contestants.

Conclusion:

This project is an electronic quiz buzzer. Fastest finger first indicators are used to test the player’s reaction time. The player’s designated number is displayed with an audio alarm when the player presses his entry button. In the buzzer round of quiz contest, the question is thrown to all the teams. The person who knows the answer hits the buzzer first and then answers the question. Sometimes two or more players hit the buzzer almost simultaneously and it is very difficult to detect which of the team has pressed the buzzer first. In television shows, where the whole event is recorded, the actions are replayed in slow motion to detect the first hit. Such slow motions are possible only where huge funds are available to conduct the show. For this reason, buzzer rounds are avoided for quiz contests held in colleges.

But this indicator reduces the probability of an error in detecting who pressed the buzzer first. Thus, in this project, we have concluded all the components for the setup of this indicator.

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Tags: Fastest Finger First Project report pdf. ppt.