The Engineering Projects

How to Upload Bootloader in Atmega328

Hello friends,hope you are fine and enjoying your lives. In today's tutorial, we will know How to Upload Bootloader in Atmega328 using Arduino UNO, which is quite simple and easy and a basic level tutorial. We all know that, Arduino UNO uses Atmega328 as a microcontroller and have you ever thought of using ATmega328 alone instead of using complete Arduino UNO. If you haven't thought yet then think now :) Yes we can use Atmega328 alone instead of using it as a whole with Arduino board. But that's not the topic of today's tutorial and I am gonna cover it soon that How can we use Atmega328 alone.

So now the questions arises that what we are gonna do with the rest of the Arduino board? As we have taken the Atmega328 out of it now there's no use of rest of the board. That's not quite right, we can buy another Atmega328 and can use it in this Arduino board. Now when you insert the new ATmega328 microcontroller in your Arduino UNO board then you will see that its not working? :( But no need to get sad because when it comes to technology then there's solution for everything. :)

Actually Arduino uses a bootloader installed on its Atmega328. It's kind of a driver for Atmega328 microcontroller, which makes it compatible with Arduino software. Normally in order to write code for Atmega328 we use AVR compiler but here because of this bootloader, we can quite easily upload the code into it simply from Arduino software. So, when you bought a new ATmega328 microcontroller then there's a need to upload bootloader in Atmega328. After installing the bootloader in Atmega328, now its ready to be plugged in Arduino UNO board and to be programmed. You should also have a look at How to get Hex File from Arduino. So, today we are gonna see How to upload Bootloader in ATmega328, let's start it.

How to Upload Bootloader in Atmega328 ???

• There are many ways to upload bootloader in ATmega328 and I am gonna share the easiest of them, which is using two Arduino UNO boards.
• So, now I suppose that you have two Arduino UNO boards and some jumper wires with you.

Note:

• If you haven't bought your Arduino UNO yet, then you can buy it from this reliable source:

• One of the Arduino board will be used as a programmer and it will upload the boatloader into second Arduino, while the second Arduino will be having the new ATmega328 microcontroller in which you wanna upload bootloader.
• So, first of all, what you need to do is to connect these two Arduino UNO boards as shown in the below figure:

• Now, in the above figure, Arduino B is acting as a programmer while Arduino A has the new ATmega328 Microcontroller in which we are gonna upload the bootloader.
• Now connect Arduino B with your computer via USB cable and both the Arduino boards will turn ON as we have connected their 5V and GND pins.
• Now open your Arduino software, and click on File menu and then Examples.
• In Examples, open ArduinoISP as shown in below figure:

• Now upload this ArduinoISP example in Arduino B board in first figure, which is acting as a programmer.
• Now Arduino B board is ready to upload the bootloader in Arduino A board.
• Now select the Arduino A board from Tools>Boards but I am not gonna do that as in our case we are using Arduino UNO for both programmer and the one getting programmed.
• Now click on Tools and then Programmer and select Arduino as ISP from the options as shown in below figure:

• Now we have done all the settings and finally we are ready to Upload Bootloader in ATmega328, so now click on Tools and then click on Burn Bootloader as shown in below figure:

• When you click on this Burn Bootloader, TX / RX leds on both the Arduino UNO boards are gonna blibk for around 30 seconds and when they are done then you will see a message on your Arduino software that Bootloader uploaded, which means you have successfully uploaded the bootloader in your ATmega328 microcontroller and now you can upload the code into it.

Note:

• After uploading the bootloader, go to Tools and the Programmer and change it back to AVRISP, otherwise you won't be able to upload the code in your Arduino UNO.
• You should also download this Arduino Library for Proteus, it will enable you to simulate your Arduino in Proteus software.

That's all for today. you should also have a look at these Arduino Projects for Beginners. I think today's tutorial was not that difficult and if you have little knowledge of Arduino then you can quite easily do it, but if still having problems then ask in comments and I will solve them.

NRF24L01+ with Arduino - Response Timed Out

Hello friends, hope you all are fine and having fun with your lives. Today I am going to share a problem and also its solution with you guys. A few days ago, I bought new NRF24L01 modules as they were needed for a project. So, today when I started working on them, I encountered a very strange problem. When I interfaced my NRF24L01 with Arduino and uploaded the transmitting and receving codes in them, I couldn't get anything on my serial terminal as I explained in my previous post Interfacing of NRF24L01 with Arduino. That was quite strange for me as I have worked on this module many times and it never troubled me before. So I keep on working on it but no luck. I even changed my RF modules as I thought may be they are faulty modules but still no luck. :(

So, the next thing came to my mind is to upload the Getting Started example from the RF24 library which I have also given in my previous post Interfacing of NRF24L01 with Arduino, and now when I checked the serial terminal, I got this error:

• Failed, response timed out.

The screenshot of this response is as follows:

As you can see in the above figure, in the last lines we are getting error that "Now sending 4679...failed. Failed, response timed out." So, that was the problem which I encountered almost for half an hour and then I finally realized what I am missing and how to solve it. Before going to the solution, let me first tell you the types of this modules.

Types of NRF24L01 Module

• When I encountered this problem, and instead of lot of efforts and not being able to resolve it, I finally thought of using the old module, so I searched for it and luckily I found one of them.
• So, now I plugged this new module with another Arduino and I checked the properties of both these modules (i.e. the old one and the new one) and for that I simple uploaded the below sketch in both of my Arduino boards and opened the serial terminal.

#include <SPI.h>
#include "nRF24L01.h"
#include "RF24.h"
#include "printf.h"

RF24 radio(9,10);

const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };

typedef enum { role_ping_out = 1, role_pong_back } role_e;

const char* role_friendly_name[] = { "invalid", "Ping out", "Pong back"};

role_e role = role_pong_back;

void setup(void)
{
 
    Serial.begin(57600);
    printf_begin();
    
    radio.begin();
    radio.setRetries(15,15);
    
    radio.openReadingPipe(1,pipes[1]);
    
    radio.startListening();
    
    radio.printDetails();
}

void loop(void)
{
}

• In this sketch, I simple print the details of NR24L01 module, so I uploaded the above sketch in both the Arduinos, one with old NRF24L01 module and the one with new NRF24L01 module, and I got the below response.

• Now I got the reason that why I am not getting the response for the same code, which worked on the old one, because the old module model was NRF24L01 while this new module is NRF24L01+ which is slightly different from NRF24L01.
• So that's the reson why I was constantly getting the Failed, response timed out error for this module. So, now lets have a look on how to resolve this issue.

How to resolve "Failed, response timed out" for NRF 24L01+ with Arduino

• So, now one thing I knew that my module is NRF24L01+ and not NRF24L01 so I need to interface NRF24L01+ with Arduino. :)
• So, I started looking online and get its datasheet which helped a lot and finally I got the thing.
• NRF24L01+ draws more current than NRF24L01 while starting up and Arduino couldn't provide that required current to it. That's the reason NRF24L01+ failed to initialize and couldn't send or receive the response.
• So, in order to remove this issue, I simply placed a Capacitor of 100uF between 3.3V and GND of Arduino and it did the magic. :)
• Detailed circuit diagram is as follows:

• So, that's the simple solution which kept me on for around an hour and then I finally got it.
• As you can see in above figure, its exactly the same circuit diagram and the only addition is the capacitor placed between 3.3V and the GND.
• After that I uploaded both the codes for receiver and transmitter which I have already posted in my old post Interfacing of NRF24L01 with Arduino and it worked like charm. :)

That's all for today, will meet you guys in the next tutorial soon. Take care!!! :)

Interfacing of RFID RC522 with Arduino

Hello friends, hope you all are fine and having fun with your lives. Today's post is about interfacing of RFID module RC522 with Arduino. RC522 is very simple yet effective module. It is an RFID module and is used for scanning RFID cards. Its a new technology and is expanding day by day. Now-a-days it is extensively used in offices where employees are issued an RFID card and their attendance is marked when they touch their card to rfid reader. We have seen it in many movies that when someone places ones card over some machine then door opens or closes. In short, its a new emerging technology which is quite useful.

I recently get a chance to work on a project in which I have to use RFID reader to scan cards. In this project I have used it for for student attendance so I thought to share it on our blog so that other engineers could get benefit out it.

Let's first have a little introduction of RFID and then we will look into how to interface RC522 with Arduino. RFID is the abbreviation of Radio frequency identification. RFID modules use electromagnetic fields to transfer data between card and the reader. Different tags are attached to objects and when we place that object in front of the reader, the reader reads that tags.Another benefit of RFID is that it doesn't require to be in a line of sight to get detected. As in barcode, the reader has to be in the line of sight to the tag and then it can scan but in RFID there's no such restriction. So, let's get started with Interfacing of RFID RC522 with Arduino.

You should also read:

• Interfacing of XBee Module with Arduino.
• Interfacing of EasyVR with Arduino.
• Interfacing of GPS Module with Arduino.

Interfacing of RFID RC522 with Arduino.

Now let's start with the interfacing of RFID RC522 with Arduino. There are many different RFID modules available in the market. The RFID module, which I am gonna use in this project, is RFID-RC522. Its quite easy to interface and works pretty fine. This module has total 8 pins as shown in the below figure:

• SDA
• SCK
• MOSI
• MISO
• IRQ
• GND
• RST
• 3.3V

It normally works on SPI protocol, when interfaced with Arduino board. Interfacing of Arduino and RC522 module is shown in below figure:

• The pin configuration is as follows:

• Now, I suppose that you have connected your RFID module with Arduino as shown in above figure and table, which is quite simple. You just need to connect total 7 pins, IRQ is not connected in our case.
• Now next step is the coding, so first of all, download this Arduino library for RFID RC522 module.

Note:

• Its a third party library, we haven't designed it, we are just sharing it for the engineers.

• Now coming to the final step. Upload the below code into your Arduino UNO.

#include <SPI.h> #include <MFRC522.h> #define RST_PIN         9 #define SS_PIN          10 MFRC522 mfrc522(SS_PIN, RST_PIN); void setup() { SPI.begin(); mfrc522.PCD_Init(); } void loop() { RfidScan(); } void dump_byte_array(byte *buffer, byte bufferSize) { for (byte i = 0; i < bufferSize; i++) { Serial.print(buffer[i] < 0x10 ? " 0" : " "); Serial.print(buffer[i], HEX); } } void RfidScan() { if ( ! mfrc522.PICC_IsNewCardPresent()) return; if ( ! mfrc522.PICC_ReadCardSerial()) return; dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size); }

• Now using this code, you can read the RFID no of your card quite easily. Now the main task is to use that number and distinguish them so for that I changed the dump_byte_array function a little, which is given below:

#include <SPI.h> #include <MFRC522.h> #define RST_PIN         9 #define SS_PIN          10 MFRC522 mfrc522(SS_PIN, RST_PIN); int RfidNo = 0; void setup() { SPI.begin(); mfrc522.PCD_Init(); } void loop() { RfidScan(); } void dump_byte_array(byte *buffer, byte bufferSize) { Serial.print("~"); if(buffer[0] == 160){RfidNo = 1;Serial.print(RfidNo);} if(buffer[0] == 176){RfidNo = 2;Serial.print(RfidNo);} if(buffer[0] == 208){RfidNo = 3;Serial.print(RfidNo);} if(buffer[0] == 224){RfidNo = 4;Serial.print(RfidNo);} if(buffer[0] == 240){RfidNo = 5;Serial.print(RfidNo);} Serial.print("!"); while(1){getFingerprintIDez();} } void RfidScan() { if ( ! mfrc522.PICC_IsNewCardPresent()) return; if ( ! mfrc522.PICC_ReadCardSerial()) return; dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size); }

• Now using the first code I get the card number for all RFID cards and then in second code I used these numbers and place the check now when first card will be placed it will show 1 on the serial port and so on for other cards.
• So, what you need to do is to use the first code and get your card number and then place them in second code and finally distinguish your cards.
• Quite simple and easy to work.
• Hope I have explained it properly but still if you get any problem ask me in comments.

NRF24L01 Arduino Interfacing

Hello friends, I hope you all are fine and enjoying. I have been working on a project these days and one portion of my current project includes the NRF24L01 Arduino Interfacing. So, I thought why not share this knowledge with you people, I hope you will learn something new and more interesting. If you don't know much about it, then you should have a look at Introduction to NRF24L01.

Few days ago, I have also posted a tutorial on XBee Arduino Interfacing, in which we have seen how to make wireless communication between two XBee Modules which is also an RF module. So, now we are gonna have a look at How to make Wireless Communication between two NRF24L01 modules. I hope you are gonna enjoy this nrf24l01 arduino Interfacing. Here's the video demonstration of NRF24L01 Arduino Interfacing:

Basics of NRF24L01

Before staring this interfacing of Arduino with 24L01, lets have a little introduction of nrf24l01 module. NRF24L01 is, in fact, a Radio Transceiver module and it operates on 2.4 GHz frequency. This module is a by default half- duplex fabricated module and it has the capability to send and receive data simultaneously. It's a very cheap & small sized module but it's features are astonishing. For example this module is capable of sending from 1 to 25 bytes of raw data simultaneously and the data transmission rate is up to 1 mega bytes per second. If we summarize all the features of this small size but big capability module then, we can say that:

• By using this NRF24L01 module we can send a message to a particular receiver.
• We can receive a message from some particular sender. (remember as I told earlier, we can do both the steps simultaneously).
• During sending the message through this module, we will have to specify the message sender's and receiver's address.
• Also we will have to specify the size of that particular message, which we are going to transmit through this module.
• In some particular applications, we also have to perform switching between the receiver and sending state. For example, if you are received a particular message then, we will stop the communication first and will read it and then you will send it. So in such situations, we have to perform the switching while sending or receiving data through this module.

Now above discussion was a brief introduction about NRF24l01 module. Now lets move towards the major theme of our project which is Interfacing of arduino with NRF24l01 module. Note:

• I encountered a problem of "Failed, response timed out" with NRF24L01+ while interfacing it with Arduino, if you got the same problem then read this post Interfacing of NRF24L01+ with Arduino - Response Timed Out. This nrf24l01 arduino example will help you in understanding this Response Timed Out problem.

NRF24L01 Arduino Interfacing

Arduino is a very powerful and versatile microcontroller board and it gives us the ease to perform multitasking. NRF24l01 has total 8 pins. The pin configuration and the function of each pin is described below:

• The very first pin is for GND and through the pin#1 of this module, ground is provided to module.
• Pin#2 of this module is to provide power supply. This pin is designated as VCC. This module generally needs 1.9 to 3.6 volts for its operation. And in most cases we will apply 3 volts to it.
• Pin#3 is designated as CE and it is used to select the mode of operation. Either you are using this module to transmit data or to receive data.
• Pin#4 is designated as CSN and it is used to enable the SPI chip, embedded on the module.
• Pin#5 is used to provide SPI clock to the module. When this pin is HIGH then, clock is enabled and when this pin is LOW then, the clock to this module is disabled.
• Pin#6 is designated as MOSI and it is used to transmit data from this module to the external circuit.
• Pin#7 is designated as MISO and if we wish to receive data through this module from any external source then, this pin is enabled.
• Pin#8 is the last pin of this module and it is designated as IRQ pin.

In order to do this Arduino with NRF24L01 communication, you will need two Arduino boards and two NRF24L01 modules. Now I suppose that you have these 4 items in your hand. So, first of all, let's do the transmitter side of NRF24L01 Arduino Interfacing.

NRF24L01 As Transmitter

• Connect your NRF24L01 with Arduino as shown in the below figure:

• Total 7 pins of NRF24L01 will be connected while the 8th pin IRQ doesn't need to connect.
• Now, next thing you need to do is to download this RF24 Library of Arduino and place it in the libraries folder of your Arduino software so that we could compile our code of nrf24l01 arduino example.

Arduino Library for NRF24L01

• We haven't designed this library, we are just sharing it for the engineers to use it in their projects.
• Now upload the below sketch into your Arduino which you want to act as Transmitter.

    #include <SPI.h>
    #include "nRF24L01.h"
    #include "RF24.h"

    RF24 radio(9,10);

    const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };
    unsigned long Command = 1;
    void setup()
    {
    Serial.begin(57600);

    radio.begin();
    radio.setRetries(15,15);
    radio.openReadingPipe(1,pipes[1]);
    radio.startListening();
    radio.printDetails();
    radio.openWritingPipe(pipes[0]);
    radio.openReadingPipe(1,pipes[1]);
    radio.stopListening();
    }

    void loop(void)
    {
    radio.stopListening();

    radio.write( &Command, sizeof(unsigned long) );

    radio.startListening();

    delay(1000);
    }

• In this code, I have marked the variable Command, this is the variable which I am sending via NRF24L01, rite now its value is 1 which you can change.
• So, if you want to send 3 you can change its value to 3.
• Now lets design the receiver side.

NRF24L01 As Receiver

• Again connect your Arduino with NRF24L01 as shown in below figure. Its same as we did for Transmitter side.

• Now upload this below code into the Receiver and you will start receiving the value coming from transmitter.

    #include <SPI.h>
    #include "nRF24L01.h"
    #include "RF24.h"

    RF24 radio(9,10);

    const uint64_t pipes[2] = { 0xF0F0F0F0E1LL, 0xF0F0F0F0D2LL };

    typedef enum { role_ping_out = 1, role_pong_back } role_e;

    const char* role_friendly_name[] = { "invalid", "Ping out", "Pong back"};

    role_e role = role_pong_back;

    void setup(void)
    {
    Serial.begin(57600);
    radio.begin();
    radio.setRetries(15,15);
    radio.openReadingPipe(1,pipes[1]);
    radio.startListening();
    radio.printDetails();
    radio.openWritingPipe(pipes[1]);
    radio.openReadingPipe(1,pipes[0]);
    radio.startListening();
    }

    void loop(void)
    {

    if ( radio.available() )
    {
    unsigned long data = 0;
    radio.read( &data, sizeof(unsigned long) );
    Serial.println(data);

    delay(20);
    }
    }

• Now open your Serial Monitor of Receiver side and you will see that you are getting "1" in the Arduino Serial Monitor, which is the value of Command variable we set in the Transmitter side, as shown in below figure:

• Its quite easy and I hope you will make it work in the first attempt but if you still got problem then ask in comments.
• I will share more Arduino Projects on this RF module soon.

So, that's all for today and I hope now you can easily Interface Arduino with NRF24L01 and can do the RF communication. If you have any problem in this Interfacing of Arduino with NRF24L01 then ask in comments and I will try my best to resolve them. Take care. :)

Interfacing PIR sensor with Arduino

Hello friends, i hope you all are fine and enjoying. Today i am going to share a new project tutorial which is Interfacing PIR sensor with Arduino. First of all lets, have a little introduction about the basics and working of the PIR sensor. PIR sensors are in fact a Passive Infrared Sensor. PIR sensors are actually electronic sensors and they are used for motion detection. They are also used to detect the Infrared waves emitting from a particular object. You should also have a look at PIR Sensor Library for Proteus, using this library now you can easily simulate your PIR Sensor in Proteus software.

PIR sensors are widely used in motion detection projects now a days. Since my today's tutorial is about interfacing of PIR sensor with Arduino micro controller. Before going to that it is necessary that we should first understand the construction and working principle of PIR sensor. So i am going to divide my tutorial into different blocks and i will describe PIR sensor from its construction to practical applications. So first of all, lets see the construction and operating principle of PIR sensor.

Construction of PIR sensor

The construction of PIR sensor is very simple and easy to understand. In the bottom or you can say in the core of the PIR sensor we have a set of sensors which are made of pyro-electric materials. The properties of this material is that when this material is exposed to heat then, it generates energy. Different methods are used to to measure this energy generated by PIR sensor. On the top of the PIR sensor and above the internal sensors we have a small screen through which infrared radiations enters into sensor. When these radiations falls on the pyro-electric material then it generates energy. Generally the size of this sensor is very small and it is available in the form of thin film in market. Many other materials are also used in collaboration with pyro-electric material like galliam nitrite and cesium nitrate and all these materials take the form of an small integrated circuit.

Operating Principle of PIR sensor

The modern studies in the field of quantum physics tells us the fact each and every object when it is placed at a temperature above absolute zero, emits some energy in the form of heat and this heat energy is in fact the form of infrared radiations.  So an other question comes into mind that why our eyes can't see these waves? It is because that these waves have infrared wavelengths and his wavelength is invisible to human eyes. if you want to detect these waves then, you have to design a proper electronic circuit.

If you see closely the name of PIR sensor which is Passive Infrared Sensor. Passive elements are those elements that don't generate their own voltages or energy. They just only measures things. So we can say that this sensor is a passive infrared sensor and it doesn't generate anything by itself. It is only capable to measure the rediations emitted by other objects around it. It measures those raditions and do some desired calculations on them.

Interfacing of PIR Sensor with Arduino

PIR sensor have total 3 pins. The configuration of each pin is shown in the image given below:

1. Pin#1 is of supply pin and it is used to connect +5 DC voltages.
2. Pin#2 is of output pin and this pin is used to collect the output signal which is collected by PIR sensor.
3. Pin#3 is marked as GND pin. This pin is used to provide ground to internal circuit of PIR sensor.

This whole configuration is also shown in the image given below:

The pin configuration of a PIR sensor is shown in the image given above. Since we have to interface the PIR sensor with Arduino micro controller. The image showing the interfacing of PIR sensor with Arduino is shown below as:

Interfacing Code

The code for interfacing Arduino micro controller with PIR sensor is given below as:

    #define pirPin 2

    int calibrationTime = 30;
    long unsigned int lowIn;
    long unsigned int pause = 5000;
    boolean lockLow = true;
    boolean takeLowTime;
    int PIRValue = 0;

    void setup()
    {
    Serial.begin(9600);
    pinMode(pirPin, INPUT);
    }

    void loop()
    {
    PIRSensor();
    }

    void PIRSensor()
    {
    if(digitalRead(pirPin) == HIGH)
    {
    if(lockLow)
    {
    PIRValue = 1;
    lockLow = false;
    Serial.println("Motion detected.");
    delay(50);
    }
    takeLowTime = true;
    }

    if(digitalRead(pirPin) == LOW)
    {

    if(takeLowTime){lowIn = millis();takeLowTime = false;}
    if(!lockLow && millis() - lowIn > pause)
    {
    PIRValue = 0;
    lockLow = true;
    Serial.println("Motion ended.");
    delay(50);
    }
    }
    }

Applications of PIR sensor

PIR sensors possess a no of applications and due to their low cost and much advanced features they are the main focus of different projects being made now a days. Some of their features and practical applications are listed below as:

• They are able to sense the detection of people and other objects.
• PIR sensors are also used in automatic lightening systems. In these type of systems, when a person comes in the vicinity of the sensor then, the lights are automatically turned ON.
• They are used in outdoor lightening systems and also in some lift lobbies. You may have observed that when a person comes in front of the lift and if the doors are being closed then, the doors are opened again. This is all due to PIR sensors.
• They are widely used in underground car parking system. At every parking position a PIR sensor is installed and when that position is vacant then, a green light glows over that place which means you can park here. And if that position has been occupied then, a red light will glow, representing that this position is already occupied.
• PIR sensor is much compatible sensor and it has the ability to detect a particular motion and the output of this system is very sensitive and doesn't have any kind of noise in it.

Alright friends, that was all from today's post. If you have any questions, fell free to ask. Till next tutorial Take Care!!! :)  

Temperature Sensor 18B20 with Arduino

Hello everyone, in today's post we are gonna have a look at how to interface temperature sensor Dallas 18B20 with Arduino. There are many temperature sensors available in market like LM35, DHT11 etc but personally I like Dallas18B20 most of all, as it gives the most accurate result up to four decimal points. It operates on single wire and sends all data through this wire. Another advantage of this wire is you can interface multiple sensors with a single data line. You should also have a look at How to use 18B20 in Proteus ISIS.

In today's post, we are gonna get value from this sensor and then print it over the Serial Terminal as well as LCD. We will get the values in degree centigrade. Its not much difficult to interface 18B20 with arduino and also an Arduino library is also availble, using which you can quite easily interface 18B20 with Arduino. Let's get started with interfacing of 18B20 with Arduino.

Note:

• In today's post,we will show the values of temperature sensor over the LCD, the complete code is given below but I am not adding the circuit diagram of LCD I have already explain it in detail which you can check at Circuit Designing of LCD with Arduino in Proteus ISIS.

Interfacing of Temperature Sensor 18B20 with Arduino

• As I explained earlier, it works on single wire and hence we are gonna need 1-wire library for Arduino along with 18B20 arduino library.
• Download both of these libraries by clicking on the below buttons:

Download One Wire Library Download Dallas Temperature Library

• After downloading the library, place it in the libraries folder of your Arduino Software.
• Now restart your Arduino software and you will find the Arduino folder in the Examples section.
• Next we need to interface our sensor 18B20 with Arduino so design your circuit as shown in below figure:

• So, connect the sensor 18B20 with Arduino as shown in the above figure, connections are quite simple and are as follows:
  • Pin # 1 of 18B20 with GND
  • Pin # 2 of 18B20 with Pin # 2 of Arduino.
  • Pin # 3 of 18B20 with GND of Arduino.
  • Add a pull up resistor of 4.7k ohm at pin # 2 of 18B20.
• Here's the images of hardware, we designed for this project, its a 20 x 4 lcd we have used:

• Below image shows the small 18B20 sensor, used in this project, it looks small but very efficient.

 

• Here's the image showing the complete project:

 

• Now, copy below code and upload it in your Arduino board and open your serial terminal.

#include <OneWire.h> #include <DallasTemperature.h> #include <LiquidCrystal.h> #define ONE_WIRE_BUS 2 OneWire oneWire(ONE_WIRE_BUS); DallasTemperature sensors(&oneWire); LiquidCrystal lcd(12, 11, 7, 6, 5, 4); void setup(void) { Serial.begin(9600); Serial.println("Welcome to TEP !!!"); Serial.println("www.TheEngineeringProjects.com"); Serial.println(); sensors.begin(); lcd.begin(20, 4); lcd.setCursor(5,0); lcd.print("Welcome to:"); lcd.setCursor(1,2); lcd.print("www.TheEngineering"); lcd.setCursor(4,3); lcd.print("Projects.com"); delay(5000); } void loop(void) { sensors.requestTemperatures(); Serial.print("Temperature : "); Serial.println(sensors.getTempCByIndex(0)); //lcd.clear(); lcd.setCursor(0,0); lcd.print("Temperature: "); lcd.print(sensors.getTempCByIndex(0)); lcd.print("C"); delay(1000); }

• After uploading the code, when I start the project, it started showing the temperature values as shown below:

• As you can see, its giving the temperature of my room which is 23.56 degree centigrade.
• I have also designed a video for more demonstration which is given below:

• It's quite a simple code and is self explanatory but still if you need help ask in comments and I will help you out.

Receive SMS with AT Commands using Sim900 and Arduino

Update: I have updated the code and removed the bug. Thanks for informing. Now this code will work perfectly.

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Hello friends, hope you all are fine and having good health. Today, as the name suggests, I am gonna post on how to Receive SMS with AT Commands using Sim900 and Arduino. I have already posted a tutorial on How to Send SMS with Arduino UNO and Sim900, so now we are gonna check the opposite. Sending SMS is quite easy, you just need to write some AT commands and write the message you wanna send and hit the Cntrl + Z and it will be sent. But receiving a text message on your SIM900 shield is a bit difficult because now you need to place a check when user will send a message. So, ideally whenever anyone send a message to your SIM900 module, you should get notified. Today, we are gonna cover this how to receive SMS with AT Commands in detail.

Now, after you get notified, there's a need to read the message as well and also who has sent this message. So, we are also gonna cover it today. So, first of all we will place a check that whenever someone sends a message to our SIM900 module, we get notified and after that we will extract the message and the mobile number of sender. We have designed this code after a lot of effort that's why this code isn't free but we haven't placed a very small amount of $20 so that engineering students can also buy it easily. We can also interface our GSM board with other microcontrollers like PIC Microcontroller as well as 8051 Microcontroller. I have also posted tutorial on How to Receive SMS with SIM900 & PIC Microcontroller and How to Send SMS with PIC Microcontroller so if you are working on PIC Microcontroller then you must give it a look. So, let's get started with How to receive SMS with AT Commands using SIM900 and Arduino.

You must also check GSM Library for Proteus, using this library you can easily simulate your GSM module in Proteus ISIS. Moreover, also have a look at Send SMS with Sim900D in Proteus ISIS in which I have designed a simulation of sms sending in Proteus ISIS.

Receive SMS with AT Commands using Sim900 and Arduino

• There are many GSM modules available in the market so it doesn't matter which one you are using unless its having SIM900 module in it.
• I have explained in my previous post that all GSM modules work on AT commands, so here first of all we are gonna have a look on AT commands we are gonna use for receiving the SMS.

1. ATE0 - IT is used to turn off the Echo of GSM shield.
2. AT - Just to check that your GSM module is working fine.
3. AT + CMGF = 1 - This command will convert the message style to text. In other words we are telling our shield that we are expecting a text message.
4. AT+CNMI=1,2,0,0,0 - This command will alert our GSM shield and now whenever it will receive message, it will automatically send an alert on the serial port.

• We are gonna use these four commands in our code and we will be able to receive text message on the GSM shield.
• Remember we have to put Enter after each of the above AT commands in order to execute it.
• Below is the first phase of the code and as you can see in this code we are simply sending these four commands serially from arduino to GSM shield.
• These are two functions I have shown below, the first function is Config() which is simply sending the commands via serially and then the Response() function which is called after every AT command and is receiving the response of that AT command.
• So, here's the partial code for How to Receive SMS with AT Commands using Sim900 and Arduino.

void Config()
{
delay(1000);
Serial.print("ATE0r");
Response();
Serial.print("ATr");
Response();
Serial.print("AT+CMGF=1r");
Response();
Serial.print("AT+CNMI=1,2,0,0,0r");
Response();
}

void Response()
{
int count = 0;
Serial.println();
while(1)
{
if(Serial.available())
{
char data =Serial.read();
if(data == 'K'){Serial.println("OK");break;}
if(data == 'R'){Serial.println("GSM Not Working");break;}
}
count++;
delay(10);
if(count == 1000){Serial.println("GSM not Found");break;}

}
}

• The response of these commands is shown below on the Serial Monitor of Arduino.
• For each AT command, we get a response "OK" from the GSM shield.

• Now, I know that I have sent all these four AT commands and my GSM shield is ready to receive the text messages and will inform me.
• So, when you send a message to your GSM shield, it will give a notification as shown in the below figure:

• Each message received by SIM900 module is start with "+CMT" and after that it has the mobile number of the sender and at the end lies the body of the message, which in our message is "www.TheEngineeringProjects.com"
• So now let's extract this mobile number and the text body from this CMT string.

Getting the SMS Text & Sender Mobile Number

• Till now we have learnt How to Receive SMS with AT Commands using Sim900 and Arduino and send you notification over the serial monitor.
• Now we have to place some checks in our code so that we could be able to get the required data out of this string.
• In order to do so, I am gonna first save this CMT string into an array, which I named as RcvdMsg[index].
• But before saving the data into this string, first I need to make sure that I am actually getting the requried string, that's aso possible that I am receving some garbage values.
• So, I placed a check first, which is checking for these four characters "+CMT", and when I got these character on my serial terminal I got sure that I have the string ready so I made the index = 0 and starting receving the string.

• Next thing I need to do is make sure that I have got the complete string, that was really a tricky part as there's no end character in the string.
• So, I used "n" null character for that. If you check the string then you can see that we are getting two null characters in complete string.
• I placed this check that when I get 2 null characters means I have got the complete string so I stopped receving the string.
• After that I simply count the charaters, in my string the sender mobile number is at posting 4 to 16 so I made a loop and save it in another array. and similarly did for the message text.
• Now when I send message after uploading this final code into my Arduino board, I get the below result on my Serial Monitor.

• Isn't it cool :) So, now we have separated the complete text as well as the sender's mobile number from our GSM string and we can use it anywhere we want.
• We can use this mobile number in the previous post code and can reply some text back and can also give a missed call to the user, anything we want. I am gonna post on How to send a call using SIM900 in the next post.
• You can buy the codefor How to Receive SMS with AT Commands using Sim900 and Arduino from our shop by clicking the below button:

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• I have highlighted all the functions in the code.
• As I always say, understand it first and then write on your own and do mistakes so that you learn.

That's all for today. I hope you have enjoyed this project named Receive SMS with AT Commands using Sim900 and Arduino. I will meet you guys in the next post. Till then have fun !!! :)