GPIO_Matlab

2013

Author: Thaufeek

Version: 1.0

Universal GPIO Board User Manual V1.0 With MATLAB

# 9/3, 2nd floor, Sree Laksmi Complex, opp, to Vivekananda Park, Girinagar, Bangalore - 560085,

Email: [email protected], Phone: 080 - 26722726

Table of contents 1. Universal GPIO Board Introduction

1.1. Overview 1.2. Board Details

2. Board Design 2.1 Hardware Schematic 2.2 Board Layout

3. Hardware Details 3.1 Light Emitting diodes 3.2 Push Buttons 3.3 Buzzer 3.4 Seven Segment Display 3.5 Potentiometer 3.6 Temperature sensor 3.7 TSOP 3.8 Light dependent Sensor 3.9 Power Switch

4. LAB Experiments with MATLAB



1. Universal GPIO Board Introduction 1.1 Overview

Ready to use Input and Output circuits are always important to experiment with any microcontroller. The Universal GPIO Board is very useful for beginners, hobbyist and students. It is suitable for carrying out quick experiments with any microcontroller and lets you access numerous peripheral devices. It provides access to pins through male connectors for wiring to the microcontroller development board.

1.2 Board Details This board has below listed interface circuits to work with:

1. 8 LEDs

2. 4 Switches

3. 1 Potentiometer

4. 1 Light Sensor (using Light Dependent Resistor)

5. 1 Temperature Sensor

6. 1 Infrared Receiver

7. 1 Buzzer

8. 1 Seven Segment Display

The above mentioned interface circuits fall into analog/digital/Input/Output as depicted below: 1. Digital Inputs to any microcontroller

Four Switches

Infrared receiver TSOP 1738

2. Analog Inputs to Any Microcontroller

Potentiometer

Temperature sensor

Light Sensor

3. Use as Digital/Analog Outputs for Any Microcontroller

LEDs

Buzzer

Seven Segment Display

2. Board Design 2.1 Hardware Schematic



Fig. 1



2.2 Board Layout

Fig. 2

Seven Segment Display

8 x LEDs

4 x Switches

Power Switch

Temperature Sensor

Potentiometer

Light Sensor Buzzer

IR Receiver (TSOP)



3. Hardware Details This section will detail every hardware module, interface parameters and pin definitions of Universal GPIO board. 3.1. Light Emitting Diodes The Universal GPIO board has eight LEDs, connected to L1, L2…L8 through a network resistor. By driving the pins HIGH (5v), the LEDs can be switched ON.

Fig. 3

3.2. Push Buttons This board provides four mini switch buttons, connected to SW1, SW2, SW3 and SW4. When the pushbutton is open (un pressed) there is no connection between the two legs of the pushbutton, so the pin is connected to GND (through the pull-up resistor) and we read a LOW. When the button is closed (pressed), it makes a connection between its two legs, connecting the pin to ground, so that we read a HIGH.



Fig. 4

3.3. Buzzer This through-hole buzzer is great for projects where you need something that sounds but don‟t have room for a full-blown speaker. We can access the buzzer from the male connector which is imprinted as Buzzer in the board.

Fig. 5

3.4. Seven Segment Display The seven segment display is a pretty simple device. It is actually combination of 8 LEDs (the decimal point is the 8th). It can be arranged so that different combinations can be used to make numerical digits. A seven segment is generally available in ten pin package. While eight pins correspond to the eight LEDs, the remaining two pins (at middle) are common and internally shorted. These segments come in two configurations, namely, Common cathode (CC) and Common anode (CA). In CC



configuration, the negative terminals of all LEDs are connected to the common pins. The common is connected to ground and a particular LED glows when its corresponding pin is given high. In CA arrangement, the common pin is given a high logic and the LED pins are given low to display a number. This board comes with common anode seven segment displays with the male connector. Use resistor that won‟t destroy led. We have connected led pin 3 and 8 to 5v through 1k resistor because it is common anode display. Note: Please don‟t use Common Cathode Display in this board because common pin is connected to 5V.

Fig. 6

3.5. Potentiometer A potentiometer, informally a pot, is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor. A potentiometer measuring instrument is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name. Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load. This board uses a 10k potentiometer and signal pin is connected to male connector. We can access the signal pin from the male connector which is imprinted as Pot in the board.



Fig. 7

3.6. Temperature Sensor The LM35 temperature sensor is a low voltage, precision centigrade temperature sensor. It provides a voltage output that is linearly proportional to the Celsius temperature. It also doesn‟t require any external calibration. The LM35 is rated to operate over a −55°C to +150°C temperature range, while the LM35C is rated for a −40°C to +110°C range. We like it because it‟s so easy to use: Just give the device a ground and 2.7 to 5.5 VDC and read the voltage on the LM35 male connector pin. The output voltage can be converted to temperature easily using the scale factor of 10 mV/°C.



Fig. 8

3.7 IR Receiver (TSOP) TSOP is an IR receiver which will help you to receive IR signal from transmitting devices like the TV remotes. The TSOP outputs a constant HIGH signal when idle and as it receives data, it tends to invert the data. i.e when an IR LED is transmitting data onto the TSOP, every time the IR led goes high, the TSOP will go LOW and vice versa. Remote control signals are often bytes of data that is encoded and transmitted by pulsing(switching ON & OFF the IR LED at a specific frequency) Most TV remote controls work at 32-40 Khz frequency and most receivers can receive this range. We can access the TSOP signal pin from the male connector which is imprinted as „TSOP‟ in the board. 3.8. Light Sensor Light-dependent resistor (LDR) or photocell is a light-controlled variable resistor. The resistance of a photo resistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photo resistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits.

Interfacing Universal GPIO Board LED’s with Arduino

Let‟s start with a quick introduction to the Arduino GPIO‟s (General Purpose Input Output) and number of LED‟s available in Universal GPIO Board. There are 14 Digital I/O Pins (of which 6 provides PWM output) and 6 Analog Input Pins in Arduino, and There are totally 8 LED‟s in Universal GPIO Board. Arduino can set to HIGH (taking the value 1) by connecting it to a voltage supply, or set to LOW (taking the value 0) by connecting it to the ground.



INTERFACING MATLAB WITH THE GPIO

BOARD MATLAB is a high-level language and interactive environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. You can use MATLAB for a range of applications, including communications, plotting and interfacing with external devices. More than a million engineers and scientists in industry and academia use MATLAB, the language of technical computing. In this Document, we will see how MATLAB can be interfaced with simple external components like a 7 Segment display, LEDs, Buzzer etc. in the GPIO board. We will use an Arduino Uno board to interface Matlab with GPIO board. MATLAB has a "serial" function that allows it to communicate through a serial port. It is used to establish serial port connection with the Arduino and demonstrate communication between simple electronic components and a MATLAB program. For demonstration purposes, Serial data‟s will be sent from MATLAB to Arduino user on a GPIO board. But how does a Serial communication work in Matlab with the Arduino???

Serial Port communication: The concept of Serial communication is simple, in serial communication data is sent one bit at a time. Although this is slower, it is simpler and can be used over longer distances.

The Arduino driver emulates a serial port - so we can communicate with it using any serial communication program. MATLAB and Arduino interaction is done to develop programs to acquire analog and digital data, and to control DC, servo, and stepper motors.

So in short, we can use Arduino serial communication to physically actuate decisions taken by a program running on, say, MATLAB in our computer. Tools used for the experiment:-

MATLAB

Arduino Uno

GPIO Board

A-B connector (USB cable suitable for Arduino BOARD)

Now we will see a number of lab experiments that MATLAB interfaces with each of the components in the GPIO Board. The list of experiments Matlab interfacing with the GPIO board are:-

1. Interfacing with all the LED

a. Blinking each LED based on user input

b. Blinking each LED serially to and fro

2. Interfacing with the Buzzer

a. Generate a Tone from the Buzzer

b. Generate different Tones from the Buzzer

3. Interfacing with the 7 Segment Display



a. Displaying the numbers 0-F continuously in ascending order and descending

order

b. Displaying the corresponding number based on user input

4. Interfacing with the Push Buttons

a. Determining which Push button is pressed

b. Increment and decrement method

5. Interfacing with the Potentiometer

6. Interfacing with the Light Dependent Resistor (LDR)

7. Interfacing with the Temperature Sensor (LM35)

Setting up the Arduino tool for communication:- The Arduino tool initial configuration is necessary for communication. Before we go into coding we need to make sure that we have selected the right Port and Board for communication. Open the tool and check the Board selected and click Arduino UNO as shown below,

But to know what port the Arduino is currently using, we need to check the port used by Arduino in the Device manager of the Windows desktop. So we need to make sure we select the same port number in the Arduino tool also. We had seen how to select the Arduino board earlier.

But to know what port the Arduino is currently using, we need to check the port used by Arduino in the Device manager of the Windows desktop. So we need to make sure we select the same port number in the Arduino tool also. We had seen how to select the Arduino board earlier. To check the Port selected we need to follow the procedure as shown below,



LAB 1: INTERFACING WITH LED

There are 8 LEDs in the GPIO board and we will try to blink each LED. Before that we need to give the correct connection from Arduino to the corresponding LEDs. We connect the LEDs 1-8 to the Arduino pins 4-11 correspondingly. The program will allow the Arduino to communicate with the LEDs in the GPIO board. Before we go into coding we need to make sure that we have selected the right Port and Board for communication.

1. BLINKING EACH LED’S BASED ON USER INPUT

Here we will try to blink each LED based on the user‟s input and the corresponding LEDs will blink. Before that we need to give the correct connection from Arduino to the corresponding LEDs. We connect the GPIO LEDs 1-8 to the Arduino pins 4-11 correspondingly. The program will interface with Arduino which will in turn communicate with the LEDs. The code is as follows, int ledPin1= 4; int ledPin2= 5; int ledPin3= 6; int ledPin4= 7; int ledPin5= 8; int ledPin6= 9; int ledPin7= 10; int ledPin8= 11; int MATLABData;



void setup() { pinMode(ledPin1,OUTPUT); pinMode(ledPin2,OUTPUT); pinMode(ledPin3,OUTPUT); pinMode(ledPin4,OUTPUT); pinMode(ledPin5,OUTPUT); pinMode(ledPin6,OUTPUT); pinMode(ledPin7,OUTPUT); pinMode(ledPin8,OUTPUT); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); Serial.begin(9600); } void loop() { if(Serial.available()>0) // if there is data to read { MATLABData=Serial.read(); // read data } if (MATLABData==1) { digitalWrite(ledPin1,HIGH); // turn light on digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==2) { digitalWrite(ledPin2,HIGH);



digitalWrite(ledPin1,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==3) { digitalWrite(ledPin3,HIGH); // turn light on digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==4) { digitalWrite(ledPin4,HIGH); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==5) { digitalWrite(ledPin5,HIGH); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); }



else if (MATLABData==6) { digitalWrite(ledPin6,HIGH); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin7,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==7) { digitalWrite(ledPin7,HIGH); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin8,LOW); } else if (MATLABData==8) { digitalWrite(ledPin8,HIGH); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } }

2. BLINKING EACH LED’S IN SERIES TO AND FRO



Here we will try to blink each LED serially one by one continuously. Before that we need to give the correct connection from Arduino to the corresponding LEDs. We connect the GPIO LEDs 1-8 to the Arduino pins 4-11 correspondingly. The program will interface with Arduino which will in turn communicate with the LEDs. The code is as follows, int ledPin= 4; int ledPin1= 5; int ledPin2= 6; int ledPin3= 7; int ledPin4= 8; int ledPin5= 9; int ledPin6= 10; int ledPin7= 11; int MATLABData; void setup() { pinMode(ledPin,OUTPUT); pinMode(ledPin1,OUTPUT); pinMode(ledPin2,OUTPUT); pinMode(ledPin3,OUTPUT); pinMode(ledPin4,OUTPUT); pinMode(ledPin5,OUTPUT); pinMode(ledPin6,OUTPUT); pinMode(ledPin7,OUTPUT); digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); Serial.begin(9600); } void loop() { if(Serial.available()>0) // if there is data to read {



MATLABData=Serial.read(); // read data } if (MATLABData==1 || MATLABData==17) { digitalWrite(ledPin,HIGH); // turn light on digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==2 || MATLABData==16) { digitalWrite(ledPin1,HIGH); digitalWrite(ledPin,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==3 || MATLABData==15) { digitalWrite(ledPin2,HIGH); // turn light on digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==4 || MATLABData==14) { digitalWrite(ledPin3,HIGH); digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin4,LOW);



digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==5 || MATLABData==13) { digitalWrite(ledPin4,HIGH); digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==6 || MATLABData==12) { digitalWrite(ledPin5,HIGH); digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==7 || MATLABData==11) { digitalWrite(ledPin6,HIGH); digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin7,LOW); } else if (MATLABData==8 || MATLABData==10) { digitalWrite(ledPin7,HIGH);



digitalWrite(ledPin,LOW); digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin4,LOW); } else if (MATLABData==9) { digitalWrite(ledPin3,HIGH); digitalWrite(ledPin,HIGH); digitalWrite(ledPin1,HIGH); digitalWrite(ledPin2,HIGH); digitalWrite(ledPin4,HIGH); digitalWrite(ledPin5,HIGH); digitalWrite(ledPin6,HIGH); digitalWrite(ledPin7,HIGH); } if (MATLABData==18) { digitalWrite(ledPin,LOW); // turn light on digitalWrite(ledPin1,LOW); digitalWrite(ledPin2,LOW); digitalWrite(ledPin3,LOW); digitalWrite(ledPin4,LOW); digitalWrite(ledPin5,LOW); digitalWrite(ledPin6,LOW); digitalWrite(ledPin7,LOW); } }



LAB 2: INTERFACING WITH A BUZZER

There is a Buzzer in the GPIO board and we will try to generate or initiate a tone in the Buzzer.

1. GENERATE THE TONE IN BUZZER

We connect the Buzzer Male pin to the Arduino pin 4. When we press 1, a tone should generate and when we press 2, the tone should get off or the Buzzer must stop the sound generated. The program must interface with Arduino which will in turn communicate with the Buzzer connected to pin 4. The coding is given below, int tune= 4; int MATLABData; void setup() { pinMode(tune,OUTPUT); digitalWrite(tune,LOW); Serial.begin(9600); } void loop() { if(Serial.available()>0) // if there is data to read { MATLABData=Serial.read(); // read data } if (MATLABData=='1') { digitalWrite(tune,HIGH); delay(50); } else if (MATLABData=='2') {



digitalWrite(tune,LOW); } }

2. GENERATE DIFFERENT NOTES FROM A BUZZER

We connect the Buzzer pin to the Arduino pin 4. This example shows how to use the tone ()

command to play different notes on multiple outputs. The tone () command works by taking

over one of the Atmega's internal timers, setting it to the frequency we want, and using the

timer to pulse an output pin. Since it's only using one timer, we can only play one note at a

time.

The coding is given below, int tune= 4; int MATLABData; void setup() { pinMode(tune,OUTPUT); digitalWrite(tune,LOW); Serial.begin(9600); } void loop() { if(Serial.available()>0) // if there is data to read { MATLABData=Serial.read(); // read data } if (MATLABData=='1') { digitalWrite(tune,HIGH); tone(4, 440, 200); delay(50); } else if (MATLABData=='2') { digitalWrite(tune,HIGH); tone(4, 294, 500); delay(50);



} else if (MATLABData=='3') { digitalWrite(tune,HIGH); tone(4, 723, 800); delay(50); } else if (MATLABData=='4') { digitalWrite(tune,LOW); } }

LAB 3: INTERFACING WITH 7 SEGMENT DISPLAY

The GPIO board consists of a Common Anode 7 Segment Display. We will communicate with the 7 segment display and the connections are shown below. Common Anode 7 Segment Display Part:-



We need to connect the corresponding pin to the Arduino as shown below

Arduino

Pin

7 Segment Pin

Connection

2 7 (A)

3 6 (B)

4 4 (C)

5 2 (D)

6 1 (E)

7 9 (F)

8 10 (G)

9 5 (DP)

Note: - If we are using a Common cathode 7 segment display it will have reversed wiring

1. DISPLAY THE CORRESPONDING NUMBER BASED ON USER INPUT

This experiment displays the numbers from 0 to F, i.e when we give a number between 0-F, the corresponding number will be displayed in the 7 Segment display. The coding for 7 Segment display is given below, int MATLABData; void setup() { pinMode(2, OUTPUT); pinMode(3, OUTPUT); pinMode(4, OUTPUT); pinMode(5, OUTPUT); pinMode(6, OUTPUT);



pinMode(7, OUTPUT); pinMode(8, OUTPUT); pinMode(9, OUTPUT); digitalWrite(9, 0); // start with the "dot" off Serial.begin(9600); } void loop() { while (Serial.available()) // if there is data to read { MATLABData=Serial.read(); // read data Serial.println(MATLABData); } // write '9' if (MATLABData==9) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); } // write '8' if (MATLABData==8) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); } // write '7' if (MATLABData==7) {



digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 1); } // write '6' if (MATLABData==6) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); } // write '5' if (MATLABData==5) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); } // write '4' if (MATLABData==4) { digitalWrite(2, 1); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); } // write '3' if (MATLABData==3) {



digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 0); } // write '2' if (MATLABData==2) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 1); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 1); digitalWrite(8, 0); } // write '1' if (MATLABData==1) { digitalWrite(2, 1); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 1); } }

2. DISPLAY THE NUMBERS 0-F CONTINUOUSLY IN ASCENDING ORDER AND

DESCENDING ORDER

This experiment is similar to the previous experiment except that it displays the numbers from 0 to F serially in ascending order and then in descending order. The code is as follows,

int MATLABData;



void setup() { pinMode(2, OUTPUT); pinMode(3, OUTPUT); pinMode(4, OUTPUT); pinMode(5, OUTPUT); pinMode(6, OUTPUT); pinMode(7, OUTPUT); pinMode(8, OUTPUT); pinMode(9, OUTPUT); digitalWrite(9, 0); // start with the "dot" off Serial.begin(9600); } void loop() { while (Serial.available()) // if there is data to read { MATLABData=Serial.read(); // read data Serial.println(MATLABData); } // write '1' // write '9' if (MATLABData==9) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); //delay(1000); } // write '8' if (MATLABData==8) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0);



digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); //delay(1000); } // write '7' if (MATLABData==7) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 1); // delay(1000); } // write '6' if (MATLABData==6) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); //delay(1000); } // write '5' if (MATLABData==5) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); //delay(1000); } // write '4' if (MATLABData==4) { digitalWrite(2, 1); digitalWrite(3, 0);



digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 0); digitalWrite(8, 0); //delay(1000); } // write '3' if (MATLABData==3) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 0); //delay(1000); } // write '2' if (MATLABData==2) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 1); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 1); digitalWrite(8, 0); // delay(1000); } // write '1' if (MATLABData==1) { digitalWrite(2, 1); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 1); digitalWrite(7, 1); digitalWrite(8, 1); // delay(1000); } // write '0'



if (MATLABData==0) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 1); // delay(4000); } if (MATLABData==10) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 1); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); // delay(4000); } if (MATLABData==11) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); // delay(4000); } if (MATLABData==12) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 1); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 1); // delay(4000); }



if (MATLABData==13) { digitalWrite(2, 0); digitalWrite(3, 0); digitalWrite(4, 0); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 1); // delay(4000); } if (MATLABData==14) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 1); digitalWrite(5, 0); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); // delay(4000); } if (MATLABData==15) { digitalWrite(2, 0); digitalWrite(3, 1); digitalWrite(4, 1); digitalWrite(5, 1); digitalWrite(6, 0); digitalWrite(7, 0); digitalWrite(8, 0); // delay(4000); } }

LAB 4: INTERFACING WITH PUSH BUTTONS There are 4 Push Buttons in the GPIO board and we could use them for any purpose and we will just see how the mere pressing of the Push buttons could set an output.

1. DETERMINING WHICH PUSH BUTTON IS PRESSED

In this experiment, we will display the increment and decrement values based on the Push Button pressed. We connect the Push Button SW2 and SW3 to 2nd and 3rd Arduino analog pins correspondingly. When we press Push button SW2, the “Push button2” is displayed in the screen until user stops and in the same way if Push button SW3 is pressed, the “Push button3” is displayed in the screen until user stops. We could use any Push Buttons as you wish, but make sure the connections are correctly given. The coding is given below,



/* Button To know which button is pressed. */ // constants won't change. They're used here to // set pin numbers: const int buttonPin1 = 2; // the number of the pushbutton1 pin const int buttonPin2 = 3; // the number of the pushbutton2 pin const int buttonPin3 = 4; // the number of the pushbutton3 pin const int buttonPin4 = 5; // the number of the pushbutton4 pin // variables will change: int buttonState1 = 0; // variable for reading the pushbutton1 status int buttonState2 = 0; // variable for reading the pushbutton2 status int buttonState3 = 0; // variable for reading the pushbutton3 status int buttonState4 = 0; // variable for reading the pushbutton4 status void setup() { Serial.begin(9600); // initialize the pushbutton pins as an input: pinMode(buttonPin1, INPUT); pinMode(buttonPin2, INPUT); pinMode(buttonPin3, INPUT); pinMode(buttonPin4, INPUT); } void loop() { // read the state of the pushbutton values: buttonState1 = digitalRead(buttonPin1); buttonState2 = digitalRead(buttonPin2); buttonState3 = digitalRead(buttonPin3); buttonState4 = digitalRead(buttonPin4); // check if the pushbutton1 is pressed. // if it is, the buttonState1 is HIGH: if (buttonState1 == HIGH) { delay(100); Serial.println("Button 1 pressed"); } // check if the pushbutton2 is pressed.



// if it is, the buttonState2 is HIGH: else if (buttonState2 == HIGH) { delay(100); Serial.println("Button 2 pressed"); } // check if the pushbutton3 is pressed. // if it is, the buttonState3 is HIGH: else if (buttonState3 == HIGH) { delay(100); Serial.println("Button 3 pressed"); } // check if the pushbutton4 is pressed. // if it is, the buttonState4 is HIGH: else if (buttonState4 == HIGH) { delay(100); Serial.println("Button 4 pressed"); } }

2. INCREMENT AND DECREMENT METHOD

In this experiment the Push Buttons and their connections are similar to the previous experiment but the final output is different from the previous experiment. We connect the Push Button SW2 and SW3 to 2nd and 3rd Arduino analog pins correspondingly. When we press Push button SW2, the number will keep increasing until the user stops and in the same way if Push button SW3 is pressed it will start decrementing the numbers from where we stopped recently and will continue decrementing until user stops. The coding is given below, /* Button To Increment the count when pushbutton1 (SW1) is pressed and decrement the count when pushbutton2 (SW2) is pressed. */ // set pin numbers: const int buttonPin1 = 2; // the number of the pushbutton1 pin const int buttonPin2 = 3; // the number of the pushbutton12 pin int buttonState1; // variable for reading the pushbutton1 status int buttonState2; // variable for reading the pushbutton2 status



int buttonPushCounter; // variable for printing the count status void setup() { Serial.begin(9600); // initialize the pushbutton pin as an input: pinMode(buttonPin1, INPUT); pinMode(buttonPin2, INPUT); } void loop() { // read the state of the pushbutton values: buttonState1 = digitalRead(buttonPin1); buttonState2 = digitalRead(buttonPin2); // check if the pushbutton1 is pressed. // if it is, the buttonState1 is HIGH: if (buttonState1 == HIGH ) { buttonPushCounter++; delay(300); Serial.println(buttonPushCounter); } // check if the pushbutton2 is pressed. // if it is, the buttonState2 is HIGH: if(buttonState2 == HIGH ) { buttonPushCounter--; delay(300); Serial.println(buttonPushCounter); } }

LAB 5: INTERFACING WITH POTENTIOMETER READING THE POTENTIOMETER VALUES



This experiment is done to read the analog values of the Potentiometer. The coding is given below, int sensorPin = A0; // select the input pin for the potentiometer int sensorValue = 0; // variable to store the value coming from the sensor void setup() { // declare the ledPin as an OUTPUT: pinMode(ledPin, OUTPUT); } void loop() { // read the value from the sensor: sensorValue = analogRead(sensorPin); // Print the Potentiometer values Serial.println(sensorValue); }

Now we will the snap shots of the outputs from Arduino. The Arduino output from the Serial monitor



LAB 6: INTERFACING WITH A TEMPERATURE SENSOR LM35

READING THE TEMPERATURE SENSOR LM35 VALUES AND PLOTTING IT CORRESPONDINGLY There is a Temperature Sensor LM35 in the GPIO board and we will read it as Celsius and Fahrenheit. We connect the Light Dependent Resistor (LDR) to any Arduino analog pins. The coding is given below, int sensorPin = A0; // select the input pin for the Temperature sensor LM35 int sensorValue = 0; // variable to store the value coming from the sensor void setup() { } void loop() { // read the value from the sensor: sensorValue = analogRead(sensorPin); // converting the sensor values to Celsius float millivolts= (sensorValue/1024.0) * 5000; float celsius= millivolts/10; // Printing the Temperature in Celsius



Serial.print(celsius); Serial.print(","); // Converting Celsius to Fahrenheit and printing the Temperature in Fahrenheit Serial.print((celsius * 9)/5 + 32); Serial.println (); delay(1000); }

Now we will the snap shots of the outputs from Arduino. The Arduino output from the Serial monitor



LAB 7: INTERFACING WITH A LIGHT DEPENDENT

RESISTOR (LDR)

READING THE LDR VALUES AND PLOTTING IT CORRESPONDINGLY There is a Light Dependent Resistor (LDR) in the GPIO board and we will read the Light Dependent Resistor (LDR) Analog values. We connect the Light Dependent Resistor (LDR) to any Arduino analog pins. The coding is given below, int sensorPin = A0; // select the input pin for the Light Dependent Resistor (LDR) int sensorValue = 0; // variable to store the value coming from the sensor void setup() { // declare the ledPin as an OUTPUT: pinMode(ledPin, OUTPUT); } void loop() { // read the value from the sensor: sensorValue = analogRead(sensorPin); // Print the Light Dependent Resistor (LDR) values Serial.println(sensorValue); }

The snap shots of the Serial Monitor readings for LDR. The Arduino output from the Serial monitor



Setting up the Matlab:- We had done with the Arduino and now we in order to communicate with the GPIO board via Arduino with Matlab, we need to write a simple serial communication code that can control the GPIO components. The Matlab code to control the GPIO board components is written in the form of Functions to minimize the coding and to control all the components from a single code rather than an individual program for each experiment listed above.

A Function is a group of statements that together perform a task. In MATLAB, Functions are defined in separate files. The name of the file and of the function should be the same. Functions can accept more than one input arguments and may return more than one output arguments.

MATLAB communicates with the Arduino board over a USB cable. This is based on a server program running on the board, which listens to commands arriving via serial port, executes the commands, and, if needed, returns a result.

Now we need to write a program in the Script file to send or receive data through Serial communication. We will write all the experiments in a single code divided into functions as explained earlier. The code for all the experiments is as follows and you need to copy each program in different script file but in the same file. Once all the codes are written, click on the green button in red circle as shown in figure below or press F5 to run the MATLAB code



The main code that interlinks all the code is given below followed by the corresponding experiments code. function interface_with_gpio()

clear classes; clear ports; delete(instrfindall); clear all; clc;

% Intialize the Serial Port s = serial('COM40'); set(s, 'FlowControl', 'hardware'); set(s, 'BaudRate', 9600); set(s, 'Parity', 'none'); set(s, 'DataBits', 8); set(s, 'StopBit', 1); set(s, 'Timeout',10); fopen(s); disp('COM40 IS OPENED'); print_numb=0; p=0; data=0;

% now we need to select the component in the GPIO board that you would like % to interface with component_selected = input('Press a number b/w 1 to 7 (1- LED, 2- Buzzer, 3-

7 Seg, 4- Push Buttons, 5- POT, 6-LDR, 7- Temp Sensor)= ');

% if condition for 7 categories and the corresponding call by function's



if (component_selected==1) disp('Interfacing with LED');

select = input('Press 1 or 2 (1- LED blinks based on user input, 2- LED

blinks serially to and fro)= ');

if (select==1)

led_user(s); else led_serial(p); end

elseif (component_selected==2) disp('Interfacing with a Buzzer');

select = input('Press 1 or 2 (1- Just produce a sound in the Buzzer, 2-

Produce different tones in the Buzzer)= ');

if (select==1) buzz_sound(print_numb); else buzz_tones(print_numb); end

elseif (component_selected==3) disp('Interfacing with the 7 Segment Display');

select = input('Press a number 1 or 2 (1- Display the corresponding number

pressed, 2- Display 0-F serially in ascending order)'); if (select==1); sev_seg_user(print_numb); else sev_seg_serial(p); end

elseif (component_selected==4) disp('Interfacing with the Push buttons');

select = input('Press a number 1 or 2 (1- Display the button number that is

pressed, 2- Display the Increment and Decrement value based on the button

pressed)= '); if (select==1); push_button_determine(data); else push_button_inc_dec(data); end

elseif (component_selected==5) disp('Interfacing with the Potentiometer'); plot_pot_values(data);



elseif (component_selected==6) disp('Interfacing with the LDR'); plot_ldr_values(data);

else disp('Interfacing with the Temperature Sensor'); plot_temp_values(data);

end end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to blink the corresponding LED based on the user

function led_user(print_numb)

% clear the used ports and classes earlier, delete the ports and clear the

screen initially clear ports; clear classes; delete(instrfindall);

s= serial('COM40', 'Baudrate', 9600); % Initializing the Serial port

with a ComPort and required Baudrate fopen(s); % Opening the Serial port disp('port is opened') print_numb= 0; % Initializing the Variable

% Press 1= Switches the LED1 ON, 2= Switches the LED1 OFF, 3= Switches the

LED2 ON, 4= Switches the LED1 OFF % 5= Switches both the LEDs ON, 6= Switches both the LEDs OFF, 7= Buzzer ON

and 8= BuzzerOFF

while 1 p = 1;



fwrite(s, p, 'uint8', 'sync');

fprintf(s, '%s', char(print_numb)); print_numb= input('Press any number between 1 and 6= ');

if print_numb== 1 disp(['Blinking LED',num2str(print_numb)])

elseif print_numb== 2 disp(['Blinking LED',num2str(print_numb)])






break

end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

% This program is to blink the LEDs serially to and fro

function led_serial(p)

clear ports; clear classes; delete(instrfindall);

s = serial('COM40','BaudRate',9600); % insert the serial

fopen(s);

pause (2)

while 1 for p = 1:18




if p== 1 || p==17 disp('Blinking LED1')

elseif p== 2 || p==16 disp('Blinking LED2')







elseif p== 9 disp('All LEDs Blinking')

elseif p== 18 disp('All LEDs OFF')

end

% wait 0.2 seconds before the next loop pause (0.2) end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

% This program is to produce sound in Buzzer

function buzz_sound(print_numb)

clear ports; clear classes;



delete(instrfindall);

% Intitializing the Serial port with a ComPort and required Baudrate

s= serial('COM40', 'Baudrate', 9600); fopen(s); % Opening the Serial port disp('port is opened') print_numb= 0;

% Initializing the Variable

% Press 1= Buzzer ON and 2 = Buzzer OFF while 1

fprintf(s, '%s', char(print_numb)); print_numb= input('Press 1 or 2= ');

if print_numb== 1 disp(['Buzzer is ON',num2str(print_numb)])

elseif print_numb== 2 disp(['Buzzer is OFF',num2str(print_numb)])

end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

% This program is to produce different tones in Buzzer

function buzz_tones(print_numb)



s= serial('COM40', 'Baudrate', 9600); fopen(s); % Opening the Serial port disp('port is opened') print_numb= 0; % Initializing the Variable



% Press 1= Generates a Tone1, 2 = Generates a Tone2, 3= Generates a Tone3, % 4- Buzzer gets to OFF mode

while 1

fprintf(s, '%s', char(print_numb)); print_numb= input('Press a number between 1 to 4= ');

if print_numb== 1 disp(['Generate tone 1',num2str(print_numb)])

elseif print_numb== 2 disp(['Generate tone 2',num2str(print_numb)])

elseif print_numb== 3 disp(['Generate tone 3',num2str(print_numb)])

elseif print_numb== 4 disp(['Buzzer is OFF',num2str(print_numb)])

end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

% This program is to display the corresponding number in the 7 segment

display given by the user

function sev_seg_user(print_numb)



s= serial('COM40', 'Baudrate', 9600); fopen(s); % Opening the Serial port disp('port is opened')

print_numb= 0; % Initializing the Variable



% Press a number between 0-9 and the corresponding number will be % displayed in 7 Segment Display

while 1

fprintf(s, '%s', char(print_numb)); print_numb= input('Press any number between 0 and 9= ');

if print_numb== 0 disp(['Displays ',num2str(print_numb)])

elseif print_numb== 1 disp(['Displays ',num2str(print_numb)])

elseif print_numb== 2 disp(['Displays number= ',num2str(print_numb)])








end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to display from 0-F serially in ascending order



function sev_seg_serial(p)



s= serial('COM40', 'Baudrate', 9600); fopen(s); % Opening the Serial port disp('port is opened')

pause (2)

while 1 for p = 0:16


if p== 0 disp('Blinking 0')

elseif p== 1 disp('Blinking 1')








elseif p== 9



disp('Blinking 9')

elseif p== 10 disp('Blinking A')

elseif p== 12 disp('Blinking B')

elseif p== 13 disp('Blinking C')

elseif p== 14 disp('Blinking D')

elseif p== 15 disp('Blinking E')

elseif p== 16 disp('Blinking F')

end

pause (1)

end end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to display as to which button is pressed

function push_button_determine(data)


sample_number = 0; serialObj = serial('COM40' , 'BaudRate', 9600); fopen(serialObj); disp('COM40 IS OPENED');

while(1)



sample_number= sample_number+1; data = fgetl(serialObj); disp(data);

if (sample_number==65535) %This is to make sure that we set the graph the right way in terms of the %x-axis. Instead of real system time this makes use of the sample number. sample_number=0; end

end

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

% This program is to display the increment and decrement values based on % the Push Button pressed and plot a 2D graph accordingly

function push_button_inc_dec(data)

clear classes; clear ports; delete(instrfindall);

serialPort = 'COM40'; scrollWidth = 10;

time = 0; data = 0; count = 0;

plotGraph = plot(time,data,'-ro',... 'LineWidth',1,... 'MarkerEdgeColor','k',... 'MarkerFaceColor',[.49 1 .63],... 'MarkerSize',2);

title('Push button incrementing and decrementing'); xlabel('Elapsed Time (s)'); ylabel('Data'); grid on;

s = serial(serialPort); disp('Port is opened now'); fopen(s);

tic;

while ishandle(plotGraph)



dat = fscanf(s,'%f'); disp('The data received is: '); disp(dat);

if(~isempty(dat) && isfloat(dat)) count = count + 1; time(count) = toc; data(count) = dat(1);

if(scrollWidth > 0) set(plotGraph,'XData',time(time > time(count)-

scrollWidth),'YData',data(time > time(count)-scrollWidth));

else set(plotGraph,'XData',time,'YData',data); end pause(0.1); end end

The MATLAB plot clearly shows that the graph that the increment value is the time SW2 is being pressed and the decrement value is the time SW3 is pressed.



*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to display the Potentiometer values in the console

% and plot the reading correspondingly

function plot_pot_values(data)

clear classes; clear ports; delete(instrfindall); clear all; close all; clc;

serialPort = 'COM40'; scrollWidth = 10;



time = 0; data = 0; count = 0;


title('Potentiometer reading'); xlabel('Elapsed Time (s)'); ylabel('Data'); grid on;


while 1 p = 3;


tic;


dat = fscanf(s,'%f'); % dat = fgetl(s);%Read Data from Serial as Float disp('The data received is: '); disp(dat);




else set(plotGraph,'XData',time,'YData',data);



end

pause(0.1); end end end

The MATLAB windows console output is as shown but before we execute the MATLAB

we need to close the Arduino Serial monitor,

The MATLAB Potentiometer Plot



*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to display the LDR values in the console

% and plot the reading correspondingly

function plot_ldr_values

clear classes; clear ports; delete(instrfindall); clear all; close all; clc;

serialPort = 'COM40'; scrollWidth = 10; time = 0; data = 0;



count = 0;


title(' Light Dependent Resistor (LDR) reading'); xlabel('Elapsed Time (s)'); ylabel('Data'); grid on;


tic;


dat = fscanf(s,'%f'); % dat = fgetl(s);%Read Data from Serial as Float disp('The data received is: '); disp(dat);




else set(plotGraph,'XData',time,'YData',data); end

pause(0.1); end end





The MATLAB Plot



*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* % This program is to display the Temperature sensor values in the console

% and plot the reading correspondingly function plot_temp_values(data)

%Clean up functions to make sure when the code is started we are t a steady %state to run the code a= instrfindall; %find all open serial ports from last instances delete(a); %delete the objects. clear all; clc; close all;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% serialPort = 'COM40'; %Change Serial as needed according to the Comport % on the arduino seen on the pc



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% plotTitle = 'Temperature Readings'; xLabel = 'Time (s)'; yLabel = 'Data'; legend('Celsius','Fahrenheit') plotGrid = 'on'; scrollWidth = 10; delay = .01;

%Init time as well as data to zero. time = 0; data = 0; data1= 0; count = 0;

figure(1); % Create one figure and plot

to the same.

%% Plotting the Celsius value plotGraph = plot(time,data,'-ro',... 'LineWidth',1,... 'MarkerEdgeColor','k',... 'MarkerFaceColor',[.49 1 .63],... 'MarkerSize',2);

hold on; %The data from last plot is retained.

%% Plotting the Fahrenheit value plotGraph1 = plot(time,data1,'-ro',... 'LineWidth',1,... 'MarkerEdgeColor','k',... 'MarkerFaceColor',[.49 1 .63],... 'MarkerSize',2);

title(plotTitle,'FontSize',25); xlabel(xLabel,'FontSize',15); ylabel(yLabel,'FontSize',15); grid(plotGrid); hold on;

s = serial(serialPort); % Assigning a variable for the serial port fopen(s); % Opening the serial port disp('Port is opened now');

tic

while ishandle(plotGraph) while ishandle(plotGraph1)

dat = fgetl(s);%Read Data from Serial as Float [a_component,b_component] = iExtractAB(dat);



%%%%%% Uncomment only if u need to see individual sensor datas. %%%%%%%%%%% disp('The temperature value in Celsius: '); disp(a_component); disp('The temperature value in Fahrenheit: '); disp(b_component);

% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% count = count + 1; %increment to keep track of samples. time(count) = toc; %#ok data(count) = str2double(a_component);%#ok data1(count) = str2double(b_component);%#ok

%Grow and shrink time axis when the data is coming in and update the %Value of the sensor in the Y-Axis. if(scrollWidth > 0) set(plotGraph, 'XData',time(time > time(count)-

scrollWidth),'YData',data(time > time(count)-scrollWidth)); set(plotGraph1,'XData',time(time > time(count)-

scrollWidth),'YData',data1(time > time(count)-scrollWidth));

else set(plotGraph, 'XData',time,'YData',data); set(plotGraph1,'XData',time,'YData',data1);

end

count = count + 1; pause(delay);

end end

end

function [a_component,b_component] = iExtractAB(dat) [a_component, remain] = strtok(dat, ','); [b_component, ~] = strtok(remain, ',');

end





The MATLAB Temperature Sensor Plot for both Celsius and Fahrenheit

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

INTERFACING SIMULINK WITH THE GPIO BOARD



Simulink is a graphical extension to MATLAB for the modeling and simulation of systems. In Simulink, systems are drawn on screen as block diagrams. Many elements of block diagrams are available (such as transfer functions, summing junctions, etc.), as well as virtual input devices (Such as function generators) and output devices (such as oscilloscopes). Simulink is integrated with MATLAB and data can be easily transferred between the programs. Simulink is supported on UNIX, Macintosh, and Windows environments, and it is included in the Student version of MATLAB for personal computers.

STARTING SIMULINK Simulink is started from the MATLAB command prompt >> Simulink Alternatively, you can hit the New Simulink Model button at the top of the MATLAB command window as shown below.

The Simulink Library Browser window should now appear on the screen. Most of the blocks needed for modeling basic systems can be found in the subfolders of the main "Simulink" folder (opened by clicking on the "+" in front of "Simulink"). Once the "Simulink" folder has been opened, the Library Browser window should look like:



In Simulink, a model is a collection of blocks which, in general, represents a system. In addition, to drawing a model into a blank model window, previously saved model files can be loaded either from the Filemenu or from the MATLAB command prompt. Example: digital_one.slx There are two major classes of items in Simulink: blocks and lines. Blocks are used to generate, modify, combine, output, and display signals. Lines are used to transfer signals from one block to another. And Lastly, Simulink provides a graphical editor, customizable block libraries, and solvers for modeling and simulating dynamic systems. It is integrated with MATLAB, enabling us to incorporate MATLAB algorithms into models and export simulation results to MATLAB for further analysis. The recent versions of Simulink have support package for Arduino (UNO, Mega2560, etc.), BeagleBone, etc. This has made it easier to simulate and upload the designs directly to the board. But Before getting to it, you need to check for some pre-requisites. Your Computer must have MATLAB-R2013 or above, (This tutorial is on MATLAB-R2013b). If you have Student version of MATLAB -2013 or 2014, it will do. Now we need to install the Arduino Support Package from the official MathWorks site. Now follow the procedure as shown below,

Set up Simulink support package for Arduino



Start MATLAB

Open MATLAB and click the Add-Ons drop down menu on the top right

Start Support Package Installer Click on Get Hardware Support Packages in the drop down menu to start the installer. Select 'Internet' as a source for installing the support package

https://learn.adafruit.com/assets/10677



Select Arduino from a list of support packages Click Next to see a list of support packages and select Arduino from the list







MathWorks Account

Click next and log in to your MathWorks account. If you don't have a MathWorks account, you can create one during the install process or by visiting this page on the MathWorks website.

Continue and Complete the Installation

Accept the license agreement on the next screen and click Next through the following screens to finish the installation

Serial Port communication:

http://www.mathworks.com/

http://www.mathworks.com/







The concept of Serial communication is simple, in serial communication data is sent one bit at a time. Although this is slower than parallel communication, which allows the transmission of an entire byte at once, it is simpler and can be used over longer distances.

One of the better features of Arduino is that it can communicate serially with MATLAB and Simulink. The Arduino driver emulates a serial port - so we can communicate with it using any serial communication program. Simulink and Arduino interaction is done to develop programs to acquire analog and digital data, and to control DC, servo, and stepper motors.

So in short, we can use Arduino serial communication to physically actuate decisions taken by a program running on, say, Simulink in our computer. Tools used for the experiment:-

MATLAB Tool (which includes Simulink)

Arduino Uno

GPIO Board

A-B connector (USB cable suitable for Arduino BOARD)

LAB 1: INTERFACING WITH LED

1. BLINKING ALL THE LED’S ON THE IO BASED MODEL



There are 8 LEDs in the GPIO board and we will try to blink all the LEDs on the IO based model. Before that we need to give the correct connection from Arduino to the corresponding LEDs. In this experiment we use,

Constant block - 1

Arduino Digital Output block - 8

We connect the LEDs L1-L8 in the IO Board to the Arduino pins 4-11 correspondingly as shown below in the snapshot of the model. Once the hardware is ready we can setup the Simulink for communication. From the Simulink Library Browser, we select the Counter or Constant Block. This block is used to give a constant high input but the Counter block gives a high input based on the sample frequency given by the user. So we select the Counter block for our experiment and we also select the 8 Digital Output Blocks for 8 LEDs from the Simulink Support Package from Arduino section. Connect the Counter block with each of the 8 Digital Output Block. Now double click on each of the 8 Digital output Block and select the corresponding pin number from 1-8. And also double click on the Counter block and select the sample time to 0.5 and save the file.

Deploying Simulink Model on Arduino Hardware:-

Note- This procedure will be shown only in the first experiment, please follow the same procedure for other experiments also. Before we run the Simulink model, we need to do further configurations. So select the Model Configuration Parameters from the Simulation icon in the top of the Simulink model as shown below,



Now select the Hardware as Arduino Uno in the Target Hardware Selection and let the Host COM Port be set as “Automatically”. And also select the Baud rate to 9600.



Once all the above parameters have been set accordingly, we can now run the hardware by clicking the “Deploy to Hardware” button as shown below and the hardware will start deploying and it may take a few minutes based on the number of blocks used and complexity.

We can see all the LEDs blinking ON and OFF with a time interval of 0.5 seconds. If any issues with running of the hardware, make sure all the above parameters and hardware are configured correctly.

2. BLINKING ALL THE LED’S SERIALLY ON THE IO BASED MODEL

In this experiment we use,

Counter block - 1

Compare to Constant block - 8


The Counter block upper limit must be set to 8 and Sample frequency as 1. The Counter block increments the given value from 1 to 8 at a Sample frequency of 1. The Compare to Constant block is used to compare the given value from the Counter block and give it accordingly to Arduino Digital Output. For example, it Compare to Constant block is equal (select this symbol in the properties == ) to 1, the Arduino pin 1 is set high , and == 2 for Arduino pin 2 and the same follows for all the other blocks correspondingly. Double click on the Arduino Digital Outputs blocks and type the corresponding pin number required. The snap shot of the model is shown below.



We deploy the hardware now once all the connections are done perfectly in the Arduino, GPIO board and in Simulink. Now once the hardware is deployed, the LEDs blink in serial fashion until the deployment is stopped



LAB 2: INTERFACING WITH A BUZZER

1. GENERATE THE TONE IN BUZZER

There is a Buzzer in the GPIO board and we will try to generate or initiate a tone in the Buzzer. Before that we need to give the correct connection from Arduino to the corresponding Buzzer pin and we can configure the Simulink for the input. In this experiment we use,

Constant block - 1


We connect the Buzzer pin to the Arduino pin 4. Once the hardware is ready we can setup the Simulink for communication. From the Simulink Library Browser, we select the Constant Block. This block is used to give a constant high input. And we also select the Digital Output Block for Buzzer from the Simulink Support Package from Arduino section. Connect the Constant block with the Digital Output Block. Now double click on the Digital output Block and select pin number 4. The model must look like this as shown below,

Final Execution:- Once all the parameters have been set accordingly, we can now run the hardware by clicking the “Deploy to Hardware” button as shown below and the hardware will start deploying and it may take a few minutes based on the number of blocks used and complexity.



Now the Buzzer produces a sound continuously.

LAB 3: INTERFACING WITH THE PUSH BUTTONS SWITCHING ON THE CORRESPONDING LEDS BASED ON THE PUSH BUTTON PRESSED A Push-button (also spelled Pushbutton) or simply Button is a simple switch mechanism for controlling some aspect of a machine or a process. Here in this experiment we will blink the corresponding LEDs based on the Push buttons pressed in Simulink. The blocks used for this experiment are,

Arduino Digital Input block - 4 (Give pin number 1-4)

Arduino Digital Output block - 8 (Give pin number 5-12)

The connections are simple; between Arduino and GPIO board just connect the Arduino pins 1-4 to Push buttons SW1- SW4 correspondingly and Arduino pins 5-12 to LEDs 1-8 correspondingly. In the Simulink, connect pin1 to pin5 and pin6, pin2 to pin7 and pin8, pin 3 to pin 9 and pin10 and lastly, pin4 to pin 11 and pin12 The model is shown below,



Now we can deploy the hardware to Arduino and once it is completely done, and now when we press the SW1 to SW4, the corresponding LEDs will blink. In the same way the Push Buttons could be used to activate any components in this way.

LAB 4: INTERFACING WITH A POTENTIOMETER

READING THE VALUES OF POTENTIOMETER A Potentiometer informally a Pot is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. As we know that there is a Potentiometer (Pot) in the GPIO board and we will be just reading the values of the Pot. Before that we need to give the correct connection from Arduino to the corresponding Pot pin and we can configure the Simulink for the serial input. We connect the Pot pin to the Arduino pin 4 in this experiment. For this experiment, we need to build 2 models to interact with each other to get the Pot values displayed in the Simulink display block. For the first model, we set the Arduino pin selected to activate the Pot pin in the GPIO board. The components used for the first model are,

Arduino Analog Input block- The Pot readings will be analog, so we use an Arduino

Analog Input block which is connected to the 4th pin in Arduino Digital to the Pot in the

GPIO board.

Arduino Digital Output block- This block is used to receive the readings in the Digital

form

Data Type Conversion block- The Data Type Conversion block converts an input signal of any Simulink data type to the data type you specify for the Output data type parameter. The input can be any real- or complex-valued signal. If the input is



real, the output is real. If the input is complex, the output is complex. We convert the input signal to uint8or an 8-bit unsigned integer

Arduino Serial Transmit block- Sends a buffered data to serial port

We need to connect the Arduino Analog Input block to both the Digital output block and the Serial Transmit block. The Serial Transmit block will receive a data converted to an unsigned integer. Once the hardware is ready we can setup the Simulink for communication. The model must look like this as shown below,

The second model is used to receive the Pot data from the first model (Serial Transmit block) and display and plot the POT values in the Display block and Scope block correspondingly. The second model consists of the following components,

Serial Receive block

Scope block- This plots the POT readings

Display block- Displays the POT values



The COM20 is the port that Arduino represents when it is connected to the PC. Once the connection is done as in the models above, we need to make sure that we have selected the Baud rate to 115200 and Target Hardware as Arduino Uno from the Tools-Run to Target Hardware in both the models. Once done, we need to deploy the first model until it is completely deployed and then deploy the second model. Once done we can see the POT readings displaying in the Display block and it keeps changing according to the change manually done by the user in POT and likewise the plotting is done simultaneously in the Scope block and can be seen if we double click the Scope block.



LAB 5: INTERFACING WITH LIGHT DEPENDENT RESISTOR (LDR)

READING THE VALUES OF LIGHT DEPENDENT RESISTOR (LDR) LDRs or Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000 000 ohms, but when they are illuminated with light, resistance drops dramatically. And we know that there is a Light Dependent Resistor (LDR) in the GPIO board and we will be just reading the values of the LDR. Before that we need to give the correct connection from Arduino to the corresponding LDR pin and we can configure the Simulink for the serial input. We connect the B LDR pin to the Arduino pin 4 in this experiment. For this experiment, we need to build 2 models to interact with each other to get the LDR values displayed in the Simulink display block. The experiment is quite similar to the previous experiment (Interfacing with POT). For the first model, we set the Arduino pin selected to activate the LDR pin in the GPIO board. The components used for the first model are,

Arduino Analog Input block- The LDR readings will be analog, so we use an Arduino

Analog Input block which is connected to the 4th pin in Arduino Digital to the Pot in the

GPIO board.


form

Data Type Conversion block- The Data Type Conversion block converts an input signal of any Simulink data type to the data type you specify for the Output data type parameter. The input can be any real- or complex-valued signal. If the input is real, the output is real. If the input is complex, the output is complex. We convert the input signal to uint8or an 8-bit unsigned integer





The second model is used to receive the LDR data from the first model (Serial Transmit block) and display and plot the LDR values in the Display block and Scope block correspondingly. The second model consists of the following components,


Scope block- This plots the LDR readings

Display block- Displays the LDR values

The COM20 is the port that Arduino represents when it is connected to the PC. Once the connection is done as in the models above, we need to make sure that we have selected the Baud rate to 115200 and Target Hardware as Arduino Uno from the Tools-Run to Target Hardware in



both the models. Once done, we need to deploy the first model which will send the LDR readings in serial port and then deploy the second model to receive it. Once done we can see the LDR readings displaying in the Display block and it keeps changing according to light intensity that falls on the LDR. The more light intensity, it resistance decreases and it exhibits more passage of current flow. So the readings received from the LDR are also plotted simultaneously in the Scope block and can be seen if we double click the Scope block.

LAB 6: INTERFACING WITH TEMPERATURE SENSOR LM35

READING THE VALUES OF TEMPERATURE SENSOR LM35 The Temperature Sensor LM35 is an integrated circuit sensor that can be used to measure temperature with an electrical output proportional to the temperature (in oC). And we know that there is a Temperature Sensor LM35 in the GPIO board and we will be just reading the values of the Temperature Sensor LM35. Before that we need to give the correct connection from Arduino to the corresponding Temperature Sensor LM35 pin and we can configure the Simulink for the serial input. We connect the Temperature Sensor LM35 pin to the Arduino pin 3 in this experiment. For this experiment, we need to build 2 models to interact with each other to get the LDR values displayed in the Simulink display block. The experiment is quite similar to the previous experiments (Interfacing with POT and Interfacing with LDR). For the first model, we set the Arduino pin selected to activate the Temperature Sensor LM35 pin in the GPIO board. The components used for the first model are,

Arduino Analog Input block- The Temperature Sensor LM35 readings will be analog,

so we use an Arduino Analog Input block which is connected to the 3rd pin in Arduino

Digital to the Pot in the GPIO board.




form

Data Type Conversion block- The Data Type Conversion block converts an input signal of any Simulink data type to the data type you specify for the Output data type parameter. The input can be any real- or complex-valued signal. If the input is real, the output is real. If the input is complex, the output is complex. We convert the input signal to uint8or an 8-bit unsigned integer



The second model is used to receive the Temperature readings from the first model (Serial Transmit block) and display and plot the temperature values in the Display block and Scope block correspondingly. The second model consists of the following components,


Scope block- This plots the temperature readings

Display block- Displays the temperature



The COM20 is the port that Arduino represents when it is connected to the PC. Once the connection is done as in the models above, we need to make sure that we have selected the Baud rate to 115200 and Target Hardware as Arduino Uno from the Tools-Run to Target Hardware in both the models. Once done, we need to deploy the first model which will send the LDR readings in serial port and then deploy the second model to receive it. Once done we can see the temperature displaying in the Display block and it keeps changing according to temperature around the sensor LM35. And the temperature is also plotted simultaneously in the Scope block and can be seen if we double click the Scope block.

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