Water Level Controller using 8051 Microcontroller

Water Level Controller using 8051 Microcontroller project will help in automatically controlling the water motor by sensing the water level in a tank. This article explains you how to detect and control the water level in an overhead tank or any other container. This system monitors the water level of the tank and automatically switches ON the motor whenever tank is empty.

The motor is switched OFF when the overhead tank or container is FULL. Here, the water level of the tank is indicated on LCD (Liquid crystal Display). Using this system, we can avoid the overflow of the water.

We have already seen How water level indicator circuit works using AVR Microcontroller in the earlier post. But, here we are designing the circuit which is used to detect and control the water level automatically in overhead tank using 8051 microcontroller.

In this system, water sensing can be done by using a set of 4 wires, which are placed at different levels in tank. DC supply probe is placed at the base of the tank. 

Construction and Output Video

Water Level Controller using 8051 Circuit Principle

This system mainly works on a principle that “water conducts electricity”. The four wires which are dipped into the tank will indicate the different water levels. Based on the outputs of these wires, microcontroller displays water level on LCD as well as controls the motor.

Initially when the tank is empty, LCD will display the message LOW and motor runs automatically. When water level reaches to half level, now LCD displays HALF and still motor runs.

When the tank is full, LCD displays FULL and motor automatically stops. Again, the motor runs when water level in the tank becomes LOW.

Water Level Controller using 8051 Microcontroller Circuit Diagram

Buy Step by Step Guide along with Code: Water Level Controller using 8051 Microcontroller »

Components Required for Water Level Controller using 8051 Microcontroller 

• AT89C51 Microcontroller (or any 8051 based Microcontroller)
• 8051 Programmer (Programming Board)
• 11.0592 MHz Quartz Crystal
• 2 x 33pF Capacitor
• 2 x 10KΩ Resistor (1/4 Watt)
• 10µF Capacitor
• Push Button
• 1KΩ x 8 Resistor Pack (for Pull – up)
• 16 x 2 LCD Display
• 5V Relay
• 4 x 2N2222 (NPN) Transistors
• DC Motor (for demonstration)
• 10KΩ Potentiometer
• 1N4007 PN Junction Diode
• Programming cable
• Connecting wires
• Power Supply
• Keil µVision IDE
• Willar Software (for burning code)
• Proteus (for circuit diagram)

How to Design Circuit for Water Level Controller using 8051 Microcontroller?

The heart of the Water Level Controller using 8051 Microcontroller project is the AT89C51 Microcontroller. The water level probes are connected to the P0.0, P0.1 and P0.2 through the transistors (they are connected to the base of the transistors through corresponding current limiting resistors). P0.0 for LOW level, P0.1 for HALF Level and P0.2 for HIGH Level.

The Collector terminals of the Transistors are connected to VCC and the Emitter terminals are connected to PORT0 terminals (P0.0, P0.1 and P0.2).

PORT1 of the microcontroller is connected to the data pins of LCD and the control pins RS, RW and EN of the LCD Display are connected to the P3.6, GND and P3.7 respectively.

For demonstration purpose, we have used a simple DC Motor Pump. It is connected to the Relay and the input to the relay is fed from P0.7 through a transistor.   

Related Post: Also read the interesting concept about How water level alarm circuit works using 555 Timer.

Algorithm for Water Level Controller Circuit 

• First configure the controller pins P0.0, P0.1 and P0.2 as inputs and P0.7 as output.
• Now, initialize the LCD.
• Continuously check the water level input pins P0.0, P0.1 and P0.2.
• If all the pins are low, then display tank as “EMPTY” on the LCD and make P0.7 pin HIGH to run the motor automatically.
• If the level is low i.e. if P0.0 is HIGH, display the water level as “LOW” and continue to run the motor.  
• A HIGH pulse on the pin P0.1 indicates that water has reached half level. So, display the same thing on LCD and run the motor normally.
• If P0.2 is HIGH, then the water level in the tank is FULL.
• Now, make the P0.7 pin as LOW to turn off the motor automatically.

Water Level Controller using 8051 Circuit Simulation Video

DOWNLOAD PROJECT CODE

How to Operate Water Level Controller Circuit using 8051 Microcontroller? 

1. Initially, write the program for Water Level Controller in Keil µVision IDE and generate the .hex file.
2. Burn the program (.hex file) to the microcontroller using external programmer and Willar Software.
3. Now give the connections as per the circuit diagram.
4. While giving the connections, make sure that there is no common connection between AC and DC supplies (if you are using an AC Motor)
5. Place the 4 water level indicating wires into the small tank (3 probes for three different levels and fourth one for common supply)
6. Switch on the supply. Now, the motor will run automatically as there is no water in the tank. (It will turn on even if the water level is LOW).
7. Now pour the water, when it reaches LOW level, then LCD displays LOW.
8. For middle level, it will display as HALF on the LCD.
9. Still if you pour the water, then the water level reaches full and the LCD displays FULL and also the motor is turned OFF automatically.
10. Switch off the motor supply and board supply.

Get an idea about How to Interface 7 Segment Display with 8051 Microcontroller

Water Level Controller Circuit Advantages

• Human effort is reduced as the system controls the motor automatically based on the water level.
• This system consumes less power.
• Simple and more reliable.

[Also Read: How To Make an Adjustable Timer ]

Applications of Water Level Controller Circuit using 8051

• Used in big buildings where the manual monitoring is difficult.
• Used in industries to control the liquid level automatically.

The post Water Level Controller using 8051 Microcontroller appeared first on Electronics Hub.

Automatic Railway Gate Controller

Automatic Railway Gate Control System is a simple but very useful project, which help is automatically opening and closing the railway gate upon detecting arrival or departure of the train.

In general, Railway gates are opened or closed manually by a gate keeper. The information about arrival of train for opening or closing of door is received from nearby station. But some railway crossings are totally unmanned and many railway accidents occur at these unmanned level crossings.

To avoid the human intervention at level crossings completely, we need to automate the process of railway gate control.

We have two different Automatic Railway Gate Control circuits mentioned in this article: using 8051 and AVR.  

Construction and Output Video

Principle of Operation

The principle of operation behind the working of this project lies in the functioning of IR Sensor. A Reflective type IR Sensor is used in this project.

In Reflective Type IR Sensor, the IR transmitter and receiver are placed side by side. When there is no obstacle in front of the sensor, the IR rays transmitted by the IR Transmitter will travel undetected as there are no rays falling on the IR Receiver.

If there is an obstacle in front of the IR Transmitter and Receiver pair, the IR Rays gets reflected off from the surface of the obstacle and are incident on the IR Receiver.

This setup can be configured to detect an object like a Train and in turn can be used to switch ON or OFF the loads like motors with the help of microcontroller. 

Circuit 1 Automatic Railway Gate Control using 8051

Circuit Diagram of Automatic Railway Gate Control using 8051

Buy Step by step Guide along with Code:Automatic Railway Gate Controller  »

Project Components

Microcontroller Section

• AT89C51 MCU
• 11.0592 MHz Quartz Crystal
• 2 x 33pF Ceramic Capacitor
• 10µF / 16V Electrolytic Capacitor
• 10KΩ Resistors x 2
• AT89C51 Programmer Board

Sensor and Load Section

• 2 x Reflective Type IR Sensor
• 2 x 1KΩ Resistor
• L293D Motor Driver IC
• Motor

Component Description

IR Sensor

• An IR sensor is used in this project to sense the arrival and departure of the train.
• An IR Sensor generally comprises of two components: an IR Transmitter and an IR Receiver. An IR Transmitter is a device that emits IR Rays.
• Similarly, an IR Receiver is a device that detects the IR Rays. Photo Diodes are the most commonly used IR Receivers. 
• The following image shows the circuit of IR Sensor used in this project. 

L293D Motor Driver

L293D is a motor driver IC used in this project to control the gate motor. L293D Motor Drive IC is a dual H-bridge type motor driver and is available in 16-pin Dual in-line Package.

With the help of this motor driver IC, we can control two motors at a time with both forward and reverse direction control for individual motors.

Motor drivers are generally used to drive high current drawing devices like DC Motors, stepper motors, high intensity lights, etc. They act as simple current amplifiers as their input is a low current signal usually from a microcontroller and their output is a high current signal to drive the loads.

Circuit Design

Major components of our project are 8051 microcontroller (AT89C51), Reflective Type IR Sensor, L293D Motor Driver IC and a Motor.

The mandatory connections for 8051 MCU include oscillator circuit, reset switch and EA Pin.

A crystal oscillator of up to 20MHz can be used as a source of external clock. In this project, an 11.0592 MHz quartz crystal oscillator is used. To complete the external oscillator circuit, two 33pF capacitors are used. Finally, the EA pin is pulled high using a 10KΩ resistor.

Now, let us see the actual connections required to implement the project. In that, first is the L293D Motor drive. The inputs (IN1 and IN2) to the motor driver (Pins 1 and 2) are given from Port 0 of the microcontroller.

But before connecting them, two 1KΩ resistors are used to pull the Port 0 pins high. Now, connect the motor driver input pins i.e. IN1 and IN2 to first two pins of Port 0 i.e. P0.0 and P0.1.

A motor is connected to OUT pins of the motor driver.

Finally connect two IR sensors to the microcontroller: one for detecting the arrival of the train and one for detecting the departure of the train.

So, connect the data outputs of the IR sensors to the pins P2.6 and P2.7 of the microcontroller.

Working

The working of the project is very simple and is explained here.

• Practically, the two IR sensors are placed at left and right side of the railway gate. The distance between the two IR sensors is dependent on the length of the train. In general we have to consider the longest train in that route.
• Now we’ll see how this circuit actually works in real time. In this image, we can see the real time representation of this project.
• If the sensor 1 detects the arrival of the train, microcontroller starts the motor with the help of motor driver in order to close the gate.

• The gate remains closed as the train passes the crossing.
• When the train crosses the gate and reaches second sensor, it detects the train and the microcontroller will open the gate.

Advantages and Applications

• An Automatic Railway Gate Control is implemented with very simple hardware and easy control.
• Human intervention at level crossings can be removed with the help of this project and many railway level crossing accidents can be prevented.

Limitations

• The system can be implemented more efficiently by incorporating more efficient sensor network.
• A combination manual wireless control and sensors based control can be used for better operation.

Circuit 2 Automatic Railway Gate Controller with High Speed Alerting System

Automatic Railway Gate Control System with High Speed Alerting System is an innovative circuit which automatically controls the operation of railway gates detecting the arrival and departure of trains at the gate.

It has detectors at the far away distance on the railway track which allows us to know the arrival and departure of the train.These detectors are given to microcontroller which activates the motors which open/close the railway gate correspondingly.

Also Read the Post: Automatic Door Bell With Object Detection

Another feature of this circuit is that it has an intelligent alerting system which detects the speed of the train that is arriving. If the speed is found to be higher than the normal speed, then the microcontroller automatically activates the alarm present at the gate.

This alerts the passengers at the railway crossing on the road about this. Also This circuit has the feature for Identification of train from other intruders i.e, animals etc .This can be implemented in manned level crossings also, as manual errors can be eliminated by automation.

Circuit Diagram of Automatic Railway Gate Controller

Fig. 2.2: Circuit Diagram of Automatic Railway Gate Controller – ElectronicsHub.Org

Circuit Operation

The operation of the circuit can be clearly explained as follows. Basically the circuit consists of four IR LED-Photo diode pairs arranged on either side of the gate such that IR LED and photodiodes are on either side of the track as shown in the figure below.

Figure 2.3: Sensor Arrangement – ElectronicsHub.Org

Initially transmitter is continuously transmitting the IR light which is made to fall on the receiver. When the train arrives it cuts the light falling on receiver. Let us assume the train is arriving from left to right, now when the train cuts the 1st sensor pair a counter is activated and when it crosses 2nd sensor pair the counter is stopped. This counter value gives the time period which is used to calculate the velocity of the train.

The sensor2 output is sent to microcontroller which makes the relay activate which causes the gate to be closed. Now when the last carriage of the train cuts the sensor4 microcontroller de-activates the relay and gates are opened.

How does the sensor know the last carriage?

Here as previously mentioned the counter value is used to calculate the velocity of the train, which means that every wheel of the carriage cuts the sensor pair within small fraction of time based on its velocity. After the last carriage is passed there is no obstacle to the sensor pair within that fraction of time hence it knows that the train has left.

One more feature of this circuit is detecting a train accurately i.e, there may be a chance that some obstacle (for e.g some animal) may cut the sensor then in such a case the counter is made to run for certain period of time (this time period is set considering the possible lowest speed of train) if the obstacle does not cut the 2nd sensor before this predefined time then this obstacle is not considered as train and gates remain opened.

Another advantage of calculating the velocity of train is, if the speed of the train crosses a limit i.e, if it is traveling at an over speed then the passengers are alerted using a by activating a buzzer.

The system basically comprises two IR LED – Photodiode pairs, which are installed on the railway track at about 1 meter apart, with the transmitter and the photodiode of each pair on the opposite sides of the track. The installation is as shown in the block diagram. The system displays the time taken by the train in crossing this distance from one pair to the other with a resolution of 0.01 second from which the speed of the vehicle can be calculated as follows:

Speed (kmph) = Distance/Time

As distance between the sensors is known and constant, the time is counted by the microcontroller and from this information, we can calculate the speed.

This circuit has been designed considering the maximum permissible speed for trains as per the traffic rule.

The microcontroller is used to process the inputs that are provided by the sensors and generate the desired outputs appropriately.

Note: Also Read the Post Automatic Washroom Light Switch

The post Automatic Railway Gate Controller appeared first on Electronics Hub.

High-tech electronics made from autumn leaves

Northern China's roadsides are peppered with deciduous phoenix trees, producing an abundance of fallen leaves in autumn. These leaves are generally burned in the colder season, exacerbating the country's air pollution problem. Investigators in Shandong, China, recently discovered a new method to convert this organic waste matter into a porous carbon material that can be used to produce high-tech electronics.

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Bluetooth Controlled Electronic Home Appliances

Bluetooth Controlled Electronic Home Appliances is a simple project, where we can control different electrical appliances and electronic devices using an Android device with the help of Bluetooth Technology.

We have already seen how a DTMF controlled home appliances system works in the earlier post. Operating conventional wall switches is difficult for physically handicapped or elder people. This project provides the solution to this problem by integrating all the electrical appliances to a control unit that can be operated by an Android application on a device (Android smart phone or Tablet).

The proposed system controls the electrical loads based on the data transmitted by the Android device. An Android application should be installed in user’s mobile or tablet to control the electrical loads. Using this Android application user can send the commands to the Bluetooth module to control the electrical loads. Wireless technology used in this project is Bluetooth. It can also be called as “Bluetooth Controlled Electronic Home Appliances” or “Android based Home Automation System” or “Remote Password Operated Electronic Home Appliances Control System”.

[Also Read: How To Make an Adjustable Timer ]

Bluetooth Controlled Electronic Home Appliances Circuit Principle

In this project, a Bluetooth module is interfaced to 8051 Microcontroller. This Bluetooth Module receives the commands from the Android application that is installed on the Android device, using wireless communication (Bluetooth Technology). The program which is written to the 8051 microcontroller communicates with Bluetooth module serially to receive the commands. Microcontroller switches the electrical loads automatically based on the commands received from the Bluetooth.

Android Based Home Automation System Circuit Block Diagram

Bluetooth Controlled Electronic Home Appliances Circuit Diagram

Components Required

Hardware Requirements

• 8051 Microcontroller (AT89C51)
• 8051 Development Board
• 8051 Programmer (Programming Board)
• Programming Cable
• 16 × 2 LCD Display
• 10KΩ Potentiometer
• Bluetooth Module (HC – 05)
• 4 – Channel Relay Module
• Loads (like Light Bulb, Fan, etc.)
• Power Supply
• Connecting wires
• If 8051 Development Board isn’t available, then you might need the following
  • 10µF Electrolytic Capacitor
  • 2 x 10KΩ Resistors (1/4 Watt)
  • 2 x 33pF Ceramic Disc Capacitors
  • 0592 MHz Quartz Crystal
  • Push Button
  • 1KΩ x 8 Resistor Pack
• If Relay Module isn’t available, then you can build the 1 – channel relay circuit (for 1 load) using the following
  • 5V or 12V Relay
  • BC547 NPN Transistor
  • 1N4007 PN Junction Diode
  • 1 KΩ Resistor (1/4 Watt)

Software Requirements

• Keil µVision IDE
• Willar Software
• Proteus (for Circuit Diagram and Simulation)
• Android Application installed on Android Device

Buy Step by step Guide along with Code:Bluetooth Controlled Electronic Home Appliances»

Android Based Home Automation System Circuit Design

This project consists of a microcontroller, 16 x 2 alphanumeric LCD, 4 – Channel Relay Module, Loads (Light Bulbs are used in the demonstration) and Bluetooth Module.

Here, AT89C51 Microcontroller is used. It is an 8 – bit microcontroller and it requires supply voltage of 5V DC. Use 7805 power supply circuit to provide 5V DC to the microcontroller. We can use 9V DC battery or 12V, 1A adapter to provide the supply to the circuit.

For the above circuit additionally you need to connect reset circuit and crystal circuit to the controller to work properly. You can ignore these connections (Power Supply Regulator, Crystal Circuit and Reset Circuit) if you are using an 8051 Development Board.

In the above circuit, the LCD display is used to indicate the status of electrical loads and also used to display received data from Bluetooth (Optional Feature).

Here, the LCD Display is interfaced to the PORT1 of the microcontroller in 8 – bit mode i.e. the data pins of the LCD are connected to PORT1. The three control pins of the LCD i.e. RS, RW and EN are connected to P3.6, GND and P3.7 pins respectively.

Also, a 10KΩ POT is connected to the Contrast Adjust pin of the LCD to control the contrast of the display.

The TX and RX Pins of the Bluetooth Module are connected to the RXD and TXD pins (P3.0 and P3.1) of the microcontroller. VCC pin (Pin 40) is connected to the +5V and GND pin (Pin 20) is connected to ground.

The Microcontroller communicates with Bluetooth Module using serial communication (UART protocol). Use a baud rate of 9600 to communicate with Bluetooth.

If you want to change the Bluetooth name and password then you need to use Bluetooth AT commands.

Below are the few Bluetooth AT commands:

• AT — Responds OK. (Used to test the Bluetooth module)
• AT+RESET — Responds OK. (Used to reset the module)
• AT+NAME? — Responds with the module name.
• AT+NAME = <name> — Responds OK. Name should be less than or equal to 20 characters.
• AT+PSWD? — Responds with the existing password.
• AT+PSWD =<password> — Sets module pairing password.

To know about all the Bluetooth AT commands refer HC-03/05 Embedded Bluetooth Serial Communication Module AT command set.

Electrical loads (like Lamp and DC motor) are connected to the P0.0 to P0.3 Pins through the 4 – Channel Relay Module. Here, relays are used to switch AC loads using small DC voltages. NPN transistors are used to drive the relays.

If you are using a relay module, then transistor and other important components to drive the relay are already embedded on the module itself.

NOTE: The Circuit Diagram shows connections of only one load. But the connections to the other loads can also be made in a similar fashion.

Algorithm for Bluetooth Controlled Electronic Home Appliances

1. Initialize the LCD and UART protocol.
2. Now read the data from Bluetooth module.
3. Display the received data on LCD.
4. Compare the received string with predefined strings and accordingly switch the electrical loads.
5. Display the status of electrical loads on LCD.

Android based Home Automation System Circuit Simulation Video

Watch the following output video of home automation system using android applications.

DOWNLOAD PROJECT CODE

How Bluetooth Controlled Electronic Home Appliances Circuit Works?

1. Write the program to the project in Keil software and create .hex file.
2.  Burn program to the controller with help of 8051 Programmer and Willar Software.
3.  Now, give the connections as per the circuit diagram.
4. While making the connections, ensure that there is no any common connection between DC and AC supplies.
5. Use 5V power supply circuit to provide regulated 5V DC to the microcontroller.
6.  Switch on the both AC and DC supplies.
7. Now relay output pins gets 230V. So, do not touch the load connected pins.
8. Install the “Bluetooth Controller” application on your Android Device (Mobile Phone or Tablet) from the following link http://ift.tt/1N007ni
9. Now pair the Android device with Bluetooth module.
10. Configure the Bluetooth Controller App as per the 8051 Program.
11. Send data to switch ON or OFF the electrical loads.

Related Post: Also read the post – RF remote control for Home Appliances.

Bluetooth Controlled Electronic Home Appliances Project Output Video

Bluetooth Controlled Electronic Home Appliances Project Applications

• This project is used to control the various electrical appliances from the remote area.
• Using this project we can control all the loads using a single remote and a control unit.

Limitations of the Circuit

• In this project the distance between control unit and android device is limited.

The post Bluetooth Controlled Electronic Home Appliances appeared first on Electronics Hub.

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Wireless Electronic Notice Board using GSM

We know the importance of notice boards in public places like railway stations, bus stations and airports. But changing notices day-to-day is a difficult task. This article explains you how to design a Wireless Electronic Notice Board using GSM technology. The project displays the data on LCD whatever we sent from the mobile.

There are many wireless communication technologies like Bluetooth, RF Communication, ZigBee, etc. but GSM Technology based communication allows long range, reliable and secure communication.

The Wireless Electronic Notice Board using GSM project, as the name suggests, is built around GSM Technology as mobile phones (that communicate through GSM Technology) have become very abundant, cheap and easy to use.

NOTE: We need a Mobile Phone to send the Message (Notice) and a GSM MODEM to receive that notice.

Related Post: RFID Based Attendance System using Microcontroller

Construction and Output Video 

Circuit Principle

When we send the message from the mobile, the GSM Modem which is connected to the Microcontroller and the display unit, will receive the message. Now, the microcontroller reads the message from the GSM Modem and displays it on LCD.

When user sends the message from the mobile, GSM modem sends the below command serially to indicate that a new message is received.

+CMTI: “SM”,3

In the above command, number “3” indicates the location of the new message i.e. it is the third message in the inbox. Now you need to read this unread message to display on LCD. The command to read the message from GSM modem is

AT+CMGR=3

Here, the number “3” indicates the location of the message to be read. After giving this command to the GSM module, it will send the below command serially.

+CMGR: “REC UNREAD”,”MD-WAYSMS”,,”13/05/20,15:31:48+34″

Electronics Hub

In the above command, “REC UNREAD” indicates that message is unread message, “MD-WAYSMS” indicates sender mobile number or name, 13/05/20 indicates the date, 15:31 indicates time and Electronics hub is the content of the message.

From the above command we need to extract message (Electronics Hub) sent by the user to display it on the notice board (LCD).

Circuit Diagram of Wireless Electronic Notice Board using GSM

Components for Wireless Electronic Notice Board using GSM 

Hardware Requirements

• 8051 Microcontroller (AT89C51)
• 8051 Programming board (Programmer with cable)
• 8051 Development Board
• SIM 900A GSM MODEM (GSM Module)
• SIM Card (for inserting in GSM Modem)
• A mobile phone with a SIM Card already inserted
• 16 x 2 LCD Display
• 10 KΩ Potentiometer
• Connecting wires
• Power Supply
• If 8051 Development Board is not available, then you need the following components
  • 2 x 10 KΩ Resistors (1/4 Watt)
  • 2 x 33pF Ceramic Disc type Capacitors
  • Push Button
  • 10µF / 16V Capacitor (Polarized)
  • 0592 MHz Quartz Crystal

Software Requirements

• Keil µVision IDE (for writing the program and generating .hex file)
• Willar Software (for burning the .hex file in to the microcontroller)
• Proteus (for circuit diagram and simulation)

Buy Step by step Guide along with Code:Wireless Electronic Notice Board using GSM »

Circuit Design

The above circuit of the Wireless Electronic Notice Board using GSM consists of 8051 Microcontroller, GSM Module (Modem) and 16 x 2 LCD. Here, the 16 x 2 LCD is used to display message and is used in 8 – bit mode. Means, we need 8 data lines to display the data. The data lines of the LCD Display are connected to PORT1 Pins. The control pins RS, RW, and E pins are connected to P3.6, GND and P3.7 pins respectively.

The GSM Module is directly connected to the microcontroller as the logic levels of both the GSM Modem and Microcontroller are already matched in the GSM Module Board. If there is no level converter on the board, then we need to use MAX232 level converter as a mediator between Controller and GSM to transfer the data.

To know more details about max232 refer Max232 Datasheet

In order to communicate with the GSM Modem, we need to send some AT commands using serial communication (UART protocol). Here, GSM SIM 900A module is used. This module requires 9600 baud rate.

To know more details about GSM go through the article GSM Interfacing with 8051 Microcontroller

Circuit Algorithm

1. Initialize the LCD and UART protocol
2. Check for the command +CMTI: “SM”,3 (Location number) to know whether the new message is received or not.
3. If you receive the command, then store message location number.
4. Now read that particular location and extract the body of the message.
5. Display the message on LCD.

Use below code to display message on LCD wirelessly using GSM

while (rx_data() ! = 0x0d);
while (rx_data() ! = 0x0a);
if (rx_data() == ‘+’)
{
if (rx_data() == ‘C’)
{
if (rx_data() == ‘M’)
{
if (rx_data() == ‘T’)
{
if(rx_data()==’I’)
{
while (rx_data() != ‘,’);
a = rx_data ();
delay_ms (10);
tx_string (“at”);
tx_data (0x0d);
tx_data (0x0a);
tx_string (“at + cmgf =1”);
tx_data (0x0d);
tx_data (0x0a);
tx_string (“at + cmgr =”);
tx_data (a);
tx_data (0x0d);
tx_data (0x0a);
while (rx_data() ! = 0x0a);
while (rx_data() != 0x0a);
while (rx_data() ! = 0x0a);
for (i=0; i<15; i++)
{
read [i]= rx_data();
}
lcd_stringxy(1,0,read);
delay_ms (5000);
}
}
}
}
}

Circuit Simulation Video

How to Operate Wireless Electronic Notice Board using GSM?

1. Write the program to the wireless electronic  notice board using Keil software
2. Now burn the program to the microcontroller with the help of hardware programmer and Willar Software.
3. Give the connections as per the circuit diagram.
4. Use power supply circuit to provide 5V DC to the microcontroller
5. Insert the SIM (Subscriber Identity Module) to the GSM module.
6.  Now switch on the supply
7. Send SMS to the GSM module using other mobile
8. Now you can see the same message on LCD.

Circuit Advantages

• No need of any complex wires to display the message on LCD as it is wireless.
• Consumes less power and easy to operate.
• The circuit is portable.

Circuit Applications

• Used in bus stations, railway stations, parks, etc. to display the messages wirelessly
• This Project can also be used in colleges and organizations.

Circuit Limitations

• Display unit must have the network to receive the message wirelessly
• As there is no password any one can send the message to display.

Download Project Code

 

The post Wireless Electronic Notice Board using GSM appeared first on Electronics Hub.

Celsius Scale Thermometer using AT89C51 and LM35

This project demonstrates the design, development and operation of the Celsius scale Thermometer using LM35 Temperature Sensor and AT89C51 Microcontroller. The circuit contains the analog temperature sensor LM35, which has the advantage of providing an output directly proportional to the Celsius Temperature, without having the need to be calibrated.

The project also consists of the 8 – bit Analog to Digital Converter ADC0804, which uses the successive approximation conversion technique. The ADC0804 is controlled by the microcontroller, which processes its output to display the resultant temperature reading on an LCD display. This article gives details about the microcontroller program, circuit design and the circuit operation.

Before going to know about this circuit, get an idea about Digital Temperature Sensor.

Construction and Output Video

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Celsius Scale Thermometer – Step by step process along with code, Free signup and you can do your own project at home after complete this course.

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Principle behind the Circuit

The circuit works on the principle of Analog to Digital conversion. The temperature is sensed by an analog temperature sensor (LM35) and this analog value is converted in to a digital value using an ADC (ADC0804). A microcontroller (AT89C51) then processes the digital signal to display the temperature reading in Celsius on the display screen (16×2 LCD).

Also Read the Post: Thermistor Temperature Sensing Alarm Circuit

Circuit Diagram of Celsius Scale Thermometer

Components Required

• 8051 Microcontroller (AT89C51)
• 8051 Development Board
• 8051 Programmer
• 16 x 2 LCD Display
• 10KΩ Potentiometer
• ADC0804 – ADC IC
• 10KΩ Resistor (1/4 Watt)
• 150pF Capacitor (Ceramic Disc Type) – Code: 151
• LM35 – Temperature Sensor
• Connecting Wires
• Power Supply
• Keil µVision IDE
• Willar Software
• You may need the following components if you do not have an 8051 Development board
  • 11.0592 MHz Quartz Crystal
  • 2 x 33pF Capacitor
  • 2 x 10KΩ Resistor (1/4 Watt)
  • 10µF Capacitor (Polarized)
  • Push Button

Celsius Scale Thermometer Circuit Design

Designing the circuit mostly involves designing the microcontroller circuit, interfacing the ADC, LM35 and LCD to the microcontroller AT89C51.

Microcontroller Circuit Design

Oscillator Circuit: The oscillator circuit consists of a crystal oscillator with oscillation frequency of 11.0592 MHz and two ceramic capacitors, each of 33pF, to ensure stability.

Reset Circuit: The reset circuit is designed using a push button, a 10KΩ resistor and an electrolyte capacitor of 10µF to ensure a reset pulse width of 100ms and a reset voltage of 1.2V.

EA Pin: Since we are not using any external memory, EA Pin is pulled high using a 10KΩ Resistor.

Interfacing ADC and LM35

LM35 Temperature Sensor IC and ADC0804 ADC IC form the input part of the circuit. LM35 consists of three pins: GND, VOUT and VS. VOUT of LM35 is connected to Analog In Pin VIN (+) of the ADC0804 IC (Pin 6).

Pin 20 (VCC) of ADC0804 is connected to +5V supply. Pins 1, 2, 7, 8 and 10 (CS’, RD’, VIN (-), AGND and GND) of ADC0804 are connected to GND. A 10KΩ Resistor is connected between the clock pins CLKR and CLKIN (Pins 19 and 4) of ADC0804. A 150pF Ceramic Capacitor is connected between CLKIN (Pin 4) and GND. Pins 3 and 5 i.e. WR’ and INTR’ are connected together.

The eight data out pins DB0 – DB7 (Pins 11 to 18) of ADC0804 are connected to PORT2 Pins of the 8051 Microcontroller.

Interfacing LCD

The RS, RW and EN pins are connected to port pins P3.6, GND and P3.7 respectively. The data pins are connected to PORT1 of the microcontroller.

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Celsius Scale Thermometer – Step by step process along with code, Free signup and you can do your own project at home after complete this course.

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Working of Celsius Scale Thermometer Circuit

The ambient temperature is sensed by LM35 temperature sensor which produces an output voltage that is proportional to the temperature at a rate of 10mV per degree Celsius. This analog voltage is fed to the Analog to Digital Converter (ADC0804), which is an 8 – bit ADC working on the principle of successive approximation conversion.

The Analog to Digital Converter ADC0804 is configured to continuously read the input Analog signals and also continuously produces the Digital Output at its Digital Out Pins. In order to make the ADC0804 to continuously read the Analog Input values, we need to tie the INTR’ pin and WR’ pin together. Also, to continuously make the digital data available at the Digital Out pins of the ADC0804, CS’ and RD’ pins must be pulled low.

The Analog to Digital Converter, continuously takes the analog signal from LM35 and converts it in to digital values. The digital output of the ADC0804 is in the form of 8 – bit binary data and these are also continuously available.

8051 Microcontroller takes this digital data and performs a simple mathematical calculation. This calculation will convert the received digital data from the ADC0804 to Temperature in Degree Celsius.

Now, the microcontroller will send this data to the LCD and display it. Since the ADC is continuously reading the Analog Data from the LM35 Temperature Sensor and sending it to the Microcontroller through the Digital Pins, the temperature will be updated at all times and the same is displayed on the LCD.

Are you interested to get some more project circuits? Then visit electronics mini projects

Algorithm Steps to Write Circuit code for Celsius Scale Thermometer

The following algorithm needs to be followed to write the code in C language.

1. Read the data from ADC0804.
2. A small calculation is performed on this received data.
3. Initialize the LCD by sending proper commands.
4. Send data to the LCD containing the temperature reading

Applications of Celsius Scale Thermometer Circuit

1. It can be used at mobile places like cars to keep a track of the temperature.
2. It can be used to control the switching of loads like motors, heaters based upon the temperature.
3. It can also be used at homes to get the temperature reading.

Limitations of the Circuit

1. It requires additional analog to digital conversion.
2. This circuit can only measure values in Celsius.

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Celsius Scale Thermometer – Step by step process along with code, Free signup and you can do your own project at home after complete this course.

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High tunability of 2-D material

A science team has precisely measured some previously obscured properties of a 2-D semiconducting material known as moly sulfide, which opens up a new avenue to applications.

Team develops novel 3-D printed high-performance polymer that could be used in space

With a new breakthrough, the high-performance polymer now could theoretically be used in any shape, size, or structure, and not just within the aerospace industry, say researchers. The same material can be found in scores of electronic devices, including cell phones and televisions.

Cheaper, greener biofuels processing catalyst

Fuels that are produced from nonpetroleum-based biological sources may become greener and more affordable, thanks to new research that examines the use of a processing catalyst made from palladium metal and bacteria.

Is there a better way to create organic bioelectronics?

Researchers reported a new fabrication technique for biocompatible neural devices that allow more precise tuning of the electrical performance of neural probes, along with improved properties for drug delivery.

Highly flexible, wearable displays

Engineers have created wearable displays for various applications including fashion, IT, and healthcare. Integrating OLED (organic light-emitting diode) into fabrics, the team developed some of the most highly flexible and reliable technology for wearable displays in the world.

Password Based Door Lock System using 8051 Microcontroller

Password Based Door Lock System using 8051 Microcontroller is a simple project where a secure password will act as a door unlocking system. Traditional lock systems using mechanical lock and key mechanism are being replaced by new advanced techniques of locking system. These techniques are an integration of mechanical and electronic devices and are highly intelligent. One of the prominent features of these innovative lock systems is their simplicity and high efficiency.

Such an automatic lock system consists of electronic control assembly, which controls the output load through a password. This output load can be a motor or a lamp or any other mechanical/electrical load.

Here, we developed an electronic code lock system using 8051 microcontroller (a Password based Door Lock System using 8051 Microcontroller), which provides control to the actuating the load. It is a simple embedded system with input from the keyboard and the output being actuated accordingly.

This system demonstrates a Password based Door Lock System using 8051 Microcontroller, wherein once the correct code or password is entered, the door is opened and the concerned person is allowed access to the secured area. Again, if another person arrives, it will ask to enter the password. If the password is wrong, then door would remain closed, denying access to the person.

Construction and Output Video

Recommended Reading: Electronic Code Lock System using Single Transistor

Principle Behind the Circuit

The main component in the circuit is 8051 controller. In this project, a 4×4 Matrix Keypad is used to enter the password. The password which is entered is compared with the predefined password.

If the entered password is correct, then the system opens the door by rotating door motor and displays the status of door on LCD. If the password is wrong, then the door is remains closed and displays “PWD is wrong” on LCD.

Circuit Diagram of Password Based Door Lock System

 

Components Required

Hardware Requirements

• 8051 Microcontroller
• 8051 Development Board
• 8051 Programmer
• 4×4 Matrix Keypad
• 16×2 LCD
• L293D Motor Driver Board
• DC Motor
• 10KΩ Potentiometer
• Connecting wires
• Power Supply
• If 8051 Development Board is not used, then the following components are needed.
  • 11.0592 MHz Quartz Crystal
  • 2 x 33pF Ceramic Capacitors
  • 2 x 10 KΩ Resistor (1/4 Watt)
  • 10 µF Capacitor (Polarized)
  • Push Button
  • 2 x 1 KΩ Resistors (for pull up)

Software Requirements 

• Keil µVision IDE
• Willar Programmer
• Proteus (for circuit diagram and simulation)

How to Design Circuit of Password based Door Lock System?

Password based door lock system using 8051 microcontroller circuit design uses five major components – a Microcontroller, an L293D Motor Driver, a DC Motor, a 4×4 Matrix Keypad and a 16×2 LCD. Here, an AT89C52 Microcontroller is used and it is an 8-bit controller. This controller requires a supply voltage of +5V DC. In order to provide regulated 5V DC voltage to the controller we need to use 7805 power supply circuit. We can use 9V DC battery or 12V, 1A adaptor as a power source.

Reset Circuit Design: The reset pin of the microcontroller is kept active till the power supply is in the specified range and a minimum oscillation level is maintained.  In other words to ensure the supply voltage does not falls below the threshold level of 1.2V and the reset pulse width is greater than 100ms (recommended for 89C52),  we need to select the values of resistor and capacitor such that RC >=100ms.  Hence, we selected a 10KΩ resistor and a 10µF electrolytic capacitor.

Oscillator Circuit Design: An 11.0592MHz crystal oscillator is used to provide external clock signal to the microcontroller. To ensure smooth operation, we need to connect two ceramic capacitors in the range of 30pF to 40pF. This crystal oscillator is connected between pin 18 and 19 of the microcontroller. Here, we used two 33pF capacitors.

Interfacing LCD, Keypad and Motor Driver: First, a 10KΩ Potentiometer is connected to the LCD Display’s Contrast Adjust Pin (Pin 3). RS, RW and E of LCD are connected to P3.0, GND and P3.2 pins respectively. The eight data lines of the LCD are connected to PORT1.

The four ROW pins of the Keypad are connected to P2.0 to P2.3 and the four COLUMN pins of the Keypad are connected to P2.4 to P2.7 pins respectively. The IN1 and IN2 of (1A and 2A) of the L293D Motor Driver are connected to PORT0 pins P0.0 and P0.1. Motor is connected between OUT1 and OUT2 (1Y and 2Y) pins of L293D.

Compilation of Microcontroller Code: Once the circuit is designed and drawn on a piece of paper, the next step is to write and compile the code. Here, we used the Keil µVision software to write the program in C language.

Prior to writing the code, general steps needs to be followed like creating a new project and selecting the target device or the required microcontroller. Once the code is written, we need to save it with .c extension and then add it to the source file group under the target folder.  The code is then compiled by pressing F7 key.

Once the code is compiled, a hex file is created.  In the next step, we use Proteus software to draw the circuit. The code is dumped into the microcontroller using an external programmer and Willar Software.

Recommend Reading: Password Based Circuit Breaker Project Circuit Diagram and Working.

Password Based Door Lock System Circuit Simulation Video

Before going to read the working of this circuit, Watch the following simulation video to get clear idea about how the above circuit works.

DOWNLOAD PROJECT CODE

Password Based Door Locking System Circuit Operation

Once the circuit is powered ON, microcontroller sends commands to the LCD to display “enter password” on LCD.  Now we need to enter the password using the keypad. Once password is entered, it displays 5 stars on LCD to indicate that controller read password successfully.

Now the controller compares the entered password with predefined password. If the password is matched, then the microcontroller makes P0.0 HIGH and P0.1 LOW, so the motor driver gets the input signals for forward motion of the motor.

As a result, the Door Motor rotates in forward direction to open the door. After a delay of 10seconds, the microcontroller makes P0.0 LOW and P0.1 HIGH, so the motor driver gets the input signals for reverse motion. As a result, the Door motor rotates in reverse direction to close the door.

If the password is not matched, then microcontroller maintains both P0.0 and P0.1 LOW. Hence, the door motor is stationary so that door remains closed.

NOTE: While giving the connections, make sure that there is no common connection between AC and DC supplies.

Buy Course along with Code: Password Based Door Lock System »

Password Based Door Lock System Algorithm

1. Initially, declare the PORT1 to LCD data pins and control pins (RS and E) to P3.0 and P3.2. Also, declare PORT2 to keypad. Also use P0.0 and P0.1 for motor driver.
2. Then, display the message “enter password” on LCD.
3. Now read the five digit password from the user.
4. Compare the entered password with the stored password.
5. If password is correct, then make P0.0 pin HIGH and P0.1 pin LOW to open the door. During this time, display “Door opening” on LCD.
6. After some time, make P0.0 pin LOW and P0.1 pin HIGH to close the door and after this display “Door closing” on LCD.
7. If the password is wrong, then display “Wrong Password” on LCD.
8. After some delay again ask to enter password.

[Also Read:Adjustable Timer With Relay Output]

Advantages of Password Based Door Lock System

• This project provides security
• Power consumption is less
• Used commonly available components
• Project is simple and easy

Applications of Password Based Door Lock System

• This simple circuit can be used at residential places to ensure better safety.
• It can be used at organizations to ensure authorized access to highly secured places.
• With a slight modification this Project can be used to control the switching of loads through password.

Limitations of Password Based Door Lock System

• It is a low range circuit, i.e. it is not possible to operate the circuit remotely.
• If you forget the password it is not possible to open the door.

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Difference Between PAM, PWM and PPM

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The post Difference Between PAM, PWM and PPM appeared first on ElProCus - Electronic Projects for Engineering Students.

Stretchable biofuel cells extract energy from sweat to power wearable devices

A team of engineers has developed stretchable fuel cells that extract energy from sweat and are capable of powering electronics, such as LEDs and Bluetooth radios. The biofuel cells generate 10 times more power per surface area than any existing wearable biofuel cells. The devices could be used to power a range of wearable devices.

Flowing fluid bends tiny hairs inside us

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Systematically studying slippery surfaces

Polymer brushes are polymers grown on surfaces, and are attractive for use in lubrication and anti-fouling applications. Researchers varied the length of the chain separating negatively and positively charged functional groups in polymer brushes to investigate how chain length affected the interaction of the polymer brushes with water. They found that the chain length influenced the ionic strength sensitivity for the hydration of the polymer brushes in water but not their water uptake or hydration structure.

Physicists resolve long-standing mystery of structure-less transition

Researchers probe a mysterious phase transition in an organic molecular conductor using synchrotron X-ray radiation.

'Electronic skin' takes wearable health monitors to the next level

Researchers have developed a new, electronic skin which can track heart rate, respiration, muscle movement and other health data. The electronic skins offers several improvements over existing trackers, including greater flexibility, portability, and the ability to stick the self-adhesive patch.

Simple Fan Regulator Circuit

In this project, we have designed a Simple Fan Regulator Circuit, which can be used to regulate the speed of a fan. This simple fan regulator circuit is implemented using very simple components.

Have you ever come across using a conventional fan voltage regulator to control the speed? Such type of regulator is called as Resistance Regulator, which works on the principle of a rheostat or a resistance potential divider arrangement.

As the steps (of the knob on a regulator box) are decreasing, this means that you are actually increasing the resistance of the circuit and hence the lower power is applied to the fan so that it becomes slower.

Obviously the power consumption by the fan will be less at lower speeds by this arrangement, but this is not an energy saving method. The voltage drop across the resistance is converted into heat losses (I²R), so the energy is dissipated in the form of heat.

This wastage of energy is more at high resistance or lower speed condition. Therefore, conventional fan voltage regulators have more energy losses. 

To know more about TRIAC, read this post: TRIAC – Basics, Working and Applications

conventional voltage regulator

Simple Electronic Voltage Regulator

Due to the advancement in power electronic technology, the alternative design of fan regulator (voltage regulator) can be easily implemented to reduce the energy losses that are caused by conventional voltage regulators.

This type of voltage regulator is an energy saving device which uses TRIAC, DIAC and potentiometric resistance. This method provides the step less control of the fan speed by deriving the required amount of power from the main supply at a given instant.

Hence, the power is conserved rather than wasted unnecessarily. Let us discuss briefly about this voltage regulator circuit and its working.

Electronic voltage regulator

Now we are going to build a simple fan regulator circuit, which is generally used to control the speed of the fan in our homes or offices. As we know that by varying the firing angle of the TRIAC, the power applied through the load is controlled which is nothing but a concept of power control using TRIAC.

The same principle is applied to the voltage regulator circuit which we are going to discuss.

Required Components for Voltage Regulator Circuit

• Resistor R1 – 10 KΩ
• Variable resistance or potentiometer R2 – 100 KΩ
• Polyester capacitor C1 – 0.1 µ F (For operating range of up to 400 V)
• DIAC, D1 – DB3
• TRIAC, T1 – BT136
• A single phase ceiling fan or AC motor – 220 V, 50 Hz (range below 200 Watts)

Voltage Regulator Circuit Connection

• Recognize the terminals of all the components for positive and negative terminal connections. Choose the ceiling fan or any AC motor provided it should be rated below 200 watts (According to the values of the components selected)
• Take a zero board or printed circuit board (PCB) and connect the circuit as given in the below diagram.
• The firing circuit consists of resistor R1, potentiometer R2, capacitor C1 and a DIAC. Connect the one terminal of the DIAC to the voltage divider combination of resistors and capacitor as shown in figure.
• Consider the data sheet of TRIAC BT 136 for recognizing the terminals of TRIAC and to know the other detailed information. Connect MT1 terminal to the neutral while MT2 to one end of the AC motor or load. And connect the gate terminal to the other end of DIAC.
• Connect the load or ceiling fan between the Phase or Line terminal of the AC power supply and MT2 terminal of TRIAC.

NOTE: For demonstration purpose, we have connected a light bulb to the simple fan regulator circuit along with a multimeter to show the voltage.

For more information on DIAC: DIAC – Introduction, Working and Applications

Circuit Diagram of Voltage Regulator using TRIAC, DIAC

Operation of the Electronic Voltage Regulator Circuit

• Before giving the power supply to this simple fan regulator circuit, keep the variable resistor or potentiometer in maximum resistance position so that no triggering is applied to TRIAC and hence the TRIAC will be in cutoff mode.
• Turn ON the power supply of the circuit and observe whether the fan is in standstill condition or not. Vary the potentiometer position slowly so that the capacitor starts charging at the time constant determined by the values of R1 and R2.
• Once the voltage across the capacitor is more than the break over voltage of the DIAC, DIAC starts conducting. Thus, the capacitor starts discharging towards the gate terminal of TRIAC through DIAC.
• Therefore, TRIAC starts conducting and hence the main current starts flowing into the fan through the closed path formed by TRIAC.
• By varying the potentiometer R2, the rate at which capacitor is going to be charged get varied this means that if the resistance is less, the capacitor will charge at a faster rate so the earlier will be the conduction of TRIAC.
• As the potentiometer resistance gradually increases, the conduction angle of TRIAC will be reduced. Hence the average power across the load will be varied.
• Due to the bidirectional control capability of both TRIAC and DIAC, it is possible to control the firing angle of the TRIAC in both positive and negative peaks of the input.

Note

• As a safety measure, test the good working condition of this circuit by applying a low voltage supply like 24V AC or 12 V AC with a small load like a low wattage bulb before connecting to the mains supply.
• If the load exceeds 200 watts, choose the higher watt capacity TRIAC in place BT 136 TRIAC.

Advantages of Simple Fan Regulator Circuit

• Continuous and step less control of the fan speed is possible
• Power saving is achieved at all the speeds by minimizing the energy losses
• Simple circuit which requires less number of components
• Efficient as compared with resistive type due to lower power consumption
• Cost-effective

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