Ks0074(75, 76) keyestudio Advanced Study Kit for Arduino

keyestudio Advanced Study Kit for Arduino

Kit Introduction

Arduino advanced study kit walks you through the basics of using the Arduino in a hands-on way. You'll learn through building several creative projects. The kit includes a selection of the most common and useful electronic components with a book of 28 projects. Starting the basics of electronics, to more complex projects, the kit will help you control the physical world with sensor and actuators.

Introduction of keyestudio UNO R3 Board

Overview

Keyestudio Uno r3 is a microcontroller board based on the ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.

The Uno r3 differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega16U2 programmed as a USB-to-serial converter.

Parameters

• 1. Microcontroller core: AVRmega328P-PU ( Processing speed 20MIPS)
• 2. Working voltage: +5V
• 3. External input voltage：+7V~+12V（suggest）
• 4. External input voltage ( extremum ): +6V≤ Vin ≤ ＋20V
• 5. Digital signal I/O interface: 14 ( 6 PWM input interface)
• 6. Analog signal input interface: 6
• 7. DC I/O interface current: 40mA
• 8. Flash capacity: 32KB( other 2k used in hootloader)
• 9. SRAM static storage capacity
• 10. EEPROM storage capacity: 512bytes
• 11. Clock frequency：16MHZ

User

• 1 | Download the Arduino Environment

Get the latest version from the download page.
When the download finishes, unzip the downloaded file. Make sure to preserve the folder structure. Double-click the folder to open it. There should be a few files and sub-folders inside.

• 2 | Connect the Board

The Arduino Uno, Mega, Duemilanove and Arduino Nano automatically draw power from either the USB connection to the computer or an external power supply. If you're using an Arduino Diecimila, you'll need to make sure that the board is configured to draw power from the USB connection. The power source is selected with a jumper, a small piece of plastic that fits onto two of the three pins between the USB and power jacks. Check that it's on the two pins closest to the USB port.
Connect the Arduino board to your computer using the USB cable. The green power LED (labelled PWR) should go on.

• 3 | Install the drivers

Installing drivers for the Arduino Uno or Arduino Mega 2560 with Windows 7, Vista, or XP:
Plug in your board and wait for Windows to begin it's driver installation process. After a few moments, the process will fail, despite its best efforts Click on the Start Menu, and open up the Control Panel.
While in the Control Panel, navigate to System and Security. Next, click on System. Once the System window is up, open the Device Manager.
Look under Ports (COM & LPT). You should see an open port named "Arduino UNO (COMxx)". If there is no COM & LPT section, look under "Other Devices" for "Unknown Device".
Right click on the "Arduino UNO (COmxx)" port and choose the "Update Driver Software" option.
Next, choose the "Browse my computer for Driver software" option.
Finally, navigate to and select the driver file named "arduino.inf", located in the "Drivers" folder of the Arduino Software download (not the "FTDI USB Drivers" sub-directory). If you are using an old version of the IDE (1.0.3 or older), choose the Uno driver file named "Arduino UNO.inf"
Windows will finish up the driver installation from there.

See also: step-by-step screenshots for installing the Uno under Windows XP. Installing drivers for the Arduino Duemilanove, Nano, or Diecimila with Windows7, Vista, or XP: When you connect the board, Windows should initiate the driver installation process (if you haven't used the computer with an Arduino board before). On Windows Vista, the driver should be automatically downloaded and installed. (Really, it works!) On Windows XP, the Add New Hardware wizard will open: When asked Can Windows connect to Windows Update to search for software? select No, not this time. Click next. Select Install from a list or specified location (Advanced) and click next. Make sure that Search for the best driver in these locations is checked; uncheck Search removable media; check Include this location in the search and browse to the drivers/FTDI USB Drivers directory of the Arduino distribution. (The latest version of the drivers can be found on the FTDI website.) Click next. The wizard will search for the driver and then tell you that a "USB Serial Converter" was found. Click finish. The new hardware wizard will appear again. Go through the same steps and select the same options and location to search. This time, a "USB Serial Port" will be found. You can check that the drivers have been installed by opening the Windows Device Mananger (in the Hardware tab of System control panel). Look for a "USB Serial Port" in the Ports section; that's the Arduino board.

• 4 | Launch the Arduino application

Double-click the Arduino application. (Note: if the Arduino software loads in the wrong language, you can change it in the preferences dialog. See the environment page for details.)

• 5 | Open the blink example

Open the LED blink example sketch: File > Examples > 1.Basics > Blink.

• 6 | Select your board

You'll need to select the entry in the Tools > Board menu that corresponds to your Arduino.

Selecting an Arduino Uno
For Duemilanove Arduino boards with an ATmega328 (check the text on the chip on the board), select Arduino Duemilanove or Nano w/ ATmega328. Previously, Arduino boards came with an ATmega168; for those, select Arduino Diecimila, Duemilanove, or Nano w/ ATmega168. (Details of the board menu entries are available on the environment page.)

• 7 | Select your serial port

Select the serial device of the Arduino board from the Tools | Serial Port menu. This is likely to be COM3 or higher (COM1and COM2 are usually reserved for hardware serial ports). To find out, you can disconnect your Arduino board and re-open the menu; the entry that disappears should be the Arduino board. Reconnect the board and select that serial port.

• 8 | Upload the program

Now, simply click the "Upload" button in the environment. Wait a few seconds - you should see the RX and TX leds on the board flashing. If the upload is successful, the message "Done uploading." will appear in the status bar. (Note: If you have an Arduino Mini, NG, or other board, you'll need to physically present the reset button on the board immediately before pressing the upload button.)

A few seconds after the upload finishes, you should see the pin 13 (L) LED on the board start to blink (in orange). If it does, congratulations! You've gotten Arduino up-and-running. If you have problems, please see the troubleshooting suggestions. You might also want to look at: the examples for using various sensors and actuators the reference for the Arduino language The text of the Arduino getting started guide is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the guide are released into the public domain.

Introduction of keyestudio Mega 2560 R3 board

Introduction

Keyestudio Mega (core to ATmega2560) is a development board (used with16MHz crystal oscillator ) of microcontroller. There 54 groups of  I/O (input/output ) digital ends (of which 14 group to do PWM output), 16 groups of simulation analogy input ends and 4 groups of UART (hardwareserial ports) in it . Because its bootloader, process can be downloaded directly with the USB and you don’t need to use other external programmer. And its power can be supplied by the USB, or the AC-to-DC adapter  and battery can be also as an external power supply.

Opening source code and using C language developed status in Java concept (cross platform) make a rapid growth of Arduino peripheral module and application. The main reason to attract Artist to use Arduino is that they can quickly use all kinds of software communication such as Arduino language and Flash or Processing and so on. and make multimedia interactive works. Development interface of Arduino IDE is based on the principle of opening source code, which you can download freely used in the thematic making, school teaching, television controlling, interactive works and so on.

Design of Power Supply

There are two choices (direct power supply trough USB or external power supply) for the power supply system of Arduino Mega, and they can be Automatic switched. External power supply can be AC-to-DC adapter or battery. Lit rang of voltage of this control board is 6V~12V, but if the supplied voltage is greater than 12V, the voltage stabilizing device will be likely overheated and overheat protection and damaging Arduino MEGA will be more likely to occur. So we suggest the power supply should be 6.5~12V in operation and recommended supply is 7.5 or 9V.

Summary

Microcontroller:ATmega2560
Operating Voltage:5V
Input Voltage (recommended):7-12V
Input Voltage (limits):6-20V
Digital I/O Pins:54 (of which 15 provide PWM output)
Analog Input Pins:16
DC Current per I/O Pin: 40 mA
DC Current for 3.3V Pin:50 mA
Flash Memory:256 KB of which 8 KB used by bootloader
SRAM:8 KB
EEPROM:4 KB
Clock Speed:16 MHz

Procedure for Installing Arduino Driver

To download the Arduino developing software on the web address: http:/arduino.cc/en/Main/Software. The downloaded file is arduino-1.0.zip,a compressed folder, to decompress it to the hard disk.

When 2560R3 Developing Board is connected to the Windows through the USB line, Windows will prompt a new USB device is found, then it will lead us into the "found new hardware wizard" window.

The next step is to install 2560R3 driver required, selecting the option of "install from a list or specific location (Senior)" and click "next" button:
To put the driver into the driver directory of Arduino 1.0 installation directory, and we need to specify this directory to be the searched directory when installing the driver.

Click "next" button, Windows begins to find and install Arduino driving procedure.
If all goes well, we will see the success interface as follows:

After the installation of Arduino driver is successful, we can find the corresponding Arduino serial port in the Windows device manager:

Well, the next is to test driver installation.
Testing code:

Copy the code above to Arduino status , select the model 2560 and port, and then upload the code. To wait a moment and the results came out, then you will see the LED flashing at D13 of your 2560r3 board and the time interval is 1s, and then we know that is ok.

Components List

No.	Product Name	Quantity	Picture
1	LED - Blue	5
2	LED - Red	5
3	LED - Yellow	5
4	LED - RGB	1
5	220 Ω resistor	8
6	10K Ω resistor	5
7	1K Ω resistor	5
8	10K Ω Pot	1
9	Buzzer (active)	1
10	Buzzer (passive)	1
11	Large button switch	4
12	Ball tilt sensor	2
13	Photo Resistor	3
14	Flame sensor	1
15	LM35 Temp Sensor	1
16	IC 74HC595N 16-pin DIP	1
17	7-seg LED 1x module	1
18	7-seg LED 4x module	1
19	8*8 LED Matrix	1
20	2x16 LCD display	1
21	IR receiver	1
22	IR remote control	1
23	Servo Motor	1
24	Stepper driver module	1
25	Stepper Motor	1
26	Joystick module	1
27	Relay module	1
28	PIR Motion Sensor	1
29	Analog Gas Sensor	1
30	ADXL345 Three Axis Acceleration Module	1
31	HC-SR04 Ultrasonic Sensor	1
32	Pin headers	40
33	830 hole Breadboard	1
34	Dupont connector wires	10
35	Jumper Wire	30
36	6-cell AA Battery pack	1
37	USB cable	1

Project Details

Project 1: Hello World

Introduction

As for starters, we will begin with something simple. In this project, you only need an Arduino and a USB cable to start the "Hello World!" experiment. This is a communication test of your Arduino and PC, also a primer project for you to have your first try of the Arduino world!

Hardware Required
1. Arduino board x1
2. USB cable x1

Sample Code
After installing driver for Arduino, let's open Arduino software and compile code that enables Arduino to print "Hello World!" under your instruction. Of course, you can compile code for Arduino to continuously echo "Hello World!" without instruction. A simple If () statement will do the instruction trick. With the onboard LED connected to pin 13, we can instruct the LED to blink first when Arduino gets an instruction and then print "Hello World!”.

//////////////////////////////////////////////////////////
int val;//define variable val
int ledpin=13;// define digital interface 13
void setup()
{
  Serial.begin(9600);// set the baud rate at 9600 to match the software set up. When connected to a specific device, (e.g. bluetooth), the baud rate needs to be the same with it.
  pinMode(ledpin,OUTPUT);// initialize digital pin 13 as output. When using I/O ports on an Arduino, this kind of set up is always needed.
}
void loop()
{
  val=Serial.read();// read the instruction or character from PC to Arduino, and assign them to Val.
  if(val=='R')// determine if the instruction or character received is “R”.
  {  // if it’s “R”,    
    digitalWrite(ledpin,HIGH);// set the LED on digital pin 13 on. 
    delay(500);
    digitalWrite(ledpin,LOW);// set the LED on digital pin 13 off.    delay(500);
    Serial.println("Hello World!");// display“Hello World！”string.
  }
}
////////////////////////////////////////////////////////////////

Result

Click serial port monitor,Input R,LED 13 will blink once,PC will receive information from Arduino: Hello World

After you choosing the right port，the experiment should be easy for you!

Project 2: LED blinking

Introduction

Blinking LED experiment is quite simple. In the "Hello World!" program, we have come across LED. This time, we are going to connect an LED to one of the digital pins rather than using LED13, which is soldered to the board. Except an Arduino and an USB cable, we will need extra parts as below:

Hardware Required
1. Red M5 LED*1
2. 220Ω resistor*1
3. Breadboard*1
4. Breadboard jumper wires* several

We follow below diagram from the experimental schematic link. Here we use digital pin 10. We connect LED to a 220 ohm resistor to avoid high current damaging the LED.

Connection for UNO R3

Connection for 2560 R3

Sample Code

//////////////////////////////////////////////////////////
int ledPin = 10; // define digital pin 10.
void setup()
{
pinMode(ledPin, OUTPUT);// define pin with LED connected as output.
}
void loop()
{
digitalWrite(ledPin, HIGH); // set the LED on.
delay(1000); // wait for a second.
digitalWrite(ledPin, LOW); // set the LED off.
delay(1000); // wait for a second
}
//////////////////////////////////////////////////////////

Result

After downloading this program, in the experiment, you will see the LED connected to pin 10 turning on and off, with an interval approximately one second. The blinking LED experiment is now completed. Thank you!

Project 3: PWM

Introduction

PWM, short for Pulse Width Modulation, is a technique used to encode analog signal level into digital ones. A computer cannot output analog voltage but only digital voltage values such as 0V or 5V. So we use a high resolution counter to encode a specific analog signal level by modulating the duty cycle of PMW. The PWM signal is also digitalized because in any given moment, fully on DC power supply is either 5V (ON), or 0V (OFF). The voltage or current is fed to the analog load (the device that uses the power) by repeated pulse sequence being ON or OFF. Being on, the current is fed to the load; being off, it's not. With adequate bandwidth, any analog value can be encoded using PWM. The output voltage value is calculated via the on and off time. Output voltage = (turn on time/pulse time) * maximum voltage value

PWM has many applications: lamp brightness regulating, motor speed regulating, sound making, etc. The following are the three basic parameters of PMW:

1. The amplitude of pulse width (minimum / maximum)
2. The pulse period (The reciprocal of pulse frequency in 1 second)
3. The voltage level（such as：0V-5V）
There are 6 PMW interfaces on Arduino, namely digital pin 3, 5, 6, 9, 10, and 11. In previous experiments, we have done "button-controlled LED", using digital signal to control digital pin, also one about potentiometer. This time, we will use a potentiometer to control the brightness of the LED.

Hardware Required
1. Potentiometer*1
2. Red M5 LED*1
3. 220Ω resistor
4. Breadboard*1
5. Breadboard jumper wires*several

The input of potentiometer is analog, so we connect it to analog port, and LED to PWM port. Different PWM signal can regulate the brightness of the LED.

Connection for UNO R3

Connection for 2560 R3

Sample Code

In the program compiling process, we will use the analogWrite (PWM interface, analog value) function. In this experiment, we will read the analog value of the potentiometer and assign the value to PWM port, so there will be corresponding change to the brightness of the LED. One final part will be displaying the analog value on the screen. You can consider this as the "analog value reading" project adding the PWM analog value assigning part. Below is a sample program for your reference.

//////////////////////////////////////////////////////////
int potpin=0;// initialize analog pin 0
int ledpin=11;//initialize digital pin 11（PWM output）
int val=0;// Temporarily store variables' value from the sensor
void setup()
{
pinMode(ledpin,OUTPUT);// define digital pin 11 as “output”
Serial.begin(9600);// set baud rate at 9600
// attention: for analog ports, they are automatically set up as “input”
}
void loop()
{
val=analogRead(potpin);// read the analog value from the sensor and assign it to val
Serial.println(val);// display value of val
analogWrite(ledpin,val/4);// turn on LED and set up brightness（maximum output of PWM is 255）
delay(10);// wait for 0.01 second
}
//////////////////////////////////////////////////////////

Result

After downloading the program, when we rotate the potentiometer knob, we can see changes of the displaying value, also obvious change of the LED brightness on the breadboard.

Project 4: Traffic light

Introduction

In the previous program, we have done the LED blinking experiment with one LED. Now, it’s time to up the stakes and do a bit more complicated experiment-traffic lights. Actually, these two experiments are similar. While in this traffic lights experiment, we use 3 LEDs with different color other than 1 LED.

Hardware Required
1. Arduino board *1
2. USB cable *1
3. Red M5 LED*1
4. Yellow M5 LED*1
5. Green M5 LED*1
6. 220Ω resistor *3
7. Breadboard*1
8. Breadboard jumper wires* several

Connection for UNO R3

Connection for 2560 R3

Sample Code

Since it is a simulation of traffic lights, the blinking time of each LED should be the same with those in traffic lights system. In this program, we use Arduino delay () function to control delay time, which is much simpler than C language.

//////////////////////////////////////////////////////////
int redled =10; // initialize digital pin 8.
int yellowled =7; // initialize digital pin 7.
int greenled =4; // initialize digital pin 4.
void setup()
{
pinMode(redled, OUTPUT);// set the pin with red LED as “output”
pinMode(yellowled, OUTPUT); // set the pin with yellow LED as “output”
pinMode(greenled, OUTPUT); // set the pin with green LED as “output”
}
void loop()
{
digitalWrite(greenled, HIGH);//// turn on green LED
delay(5000);// wait 5 seconds
digitalWrite(greenled, LOW); // turn off green LED
for(int i=0;i<3;i++)// blinks for 3 times
{
delay(500);// wait 0.5 second
digitalWrite(yellowled, HIGH);// turn on yellow LED
delay(500);// wait 0.5 second
digitalWrite(yellowled, LOW);// turn off yellow LED
} 
delay(500);// wait 0.5 second
digitalWrite(redled, HIGH);// turn on red LED
delay(5000);// wait 5 second
digitalWrite(redled, LOW);// turn off red LED
}
//////////////////////////////////////////////////////////

Result

When the uploading process is completed, we can see traffic lights of our own design. Note: this circuit design is very similar with the one in LED chase effect. The green light will be on for 5 seconds, and then off., followed by the yellow light blinking for 3 times, and then the red light on for 5 seconds, forming a cycle. Cycle then repeats. Experiment is now completed, thank you.

Project 5: LED chasing effect

Introduction

We often see billboards composed of colorful LEDs. They are constantly changing to form various effects. In this experiment, we compile a program to simulate chase effect.

Hardware Required
1. Led x6
2. 220Ω resistor x6
3. Colorful breadboard wires

Connection for UNO R3

Connection for 2560 R3

Sample Code

//////////////////////////////////////////////////////////
int BASE = 2 ;  // the I/O pin for the first LED
int NUM = 6;   // number of LEDs

void setup()
{
   for (int i = BASE; i < BASE + NUM; i ++) 
   {
     pinMode(i, OUTPUT);   // set I/O pins as output
   }
}

void loop()
{
   for (int i = BASE; i < BASE + NUM; i ++) 
   {
     digitalWrite(i, LOW);    // set I/O pins as “low”, turn off LEDs one by one.
     delay(200);        // delay
   }
   for (int i = BASE; i < BASE + NUM; i ++) 
   {
     digitalWrite(i, HIGH);    // set I/O pins as “high”, turn on LEDs one by one
     delay(200);        // delay
   }  
}
//////////////////////////////////////////////////////////

Result

You can see the LEDs blink by sequence.

Project 6: Button-controlled LED

Introduction

I/O port means interface for INPUT and OUTPUT. Up until now, we have only used its OUTPUT function. In this experiment, we will try to use the input function, which is to read the output value of device connecting to it. We use 1 button and 1 LED using both input and output to give you a better understanding of the I/O function. Button switches, familiar to most of us, are a switch value (digital value) component. When it's pressed, the circuit is in closed (conducting) state.

Hardware Required
1. Button switch*1
2. Red M5 LED*1
3. 220Ω resistor*1
4. 10KΩ resistor*1
5. Breadboard*1
6. Breadboard jumper wires*several

Connection for UNO R3

Connection for 2560 R3

Sample Code

Now, let's begin the compiling. When the button is pressed, the LED will be on. After the previous study, the coding should be easy for you. In this program, we add a statement of judgment. Here, we use an if () statement. Arduino IDE is based on C language, so statements of C language such as while, switch etc. can certainly be used for Arduino program. When we press the button, pin 7 will output high level. We can program pin 11 to output high level and turn on the LED. When pin 7 outputs low level, pin 11 also outputs low level and the LED remains off.

//////////////////////////////////////////////////////////
int ledpin=11;// initialize pin 11
int inpin=7;// initialize pin 7
int val;// define val
void setup()
{
pinMode(ledpin,OUTPUT);// set LED pin as “output”
pinMode(inpin,INPUT);// set button pin as “input”
}
void loop()
{
val=digitalRead(inpin);// read the level value of pin 7 and assign if to val
if(val==LOW)// check if the button is pressed, if yes, turn on the LED
{ digitalWrite(ledpin,LOW);}
else
{ digitalWrite(ledpin,HIGH);}
}
//////////////////////////////////////////////////////////

Result

When the button is pressed, LED is on, otherwise, LED remains off. After the above process, the button controlled LED experiment is completed. The simple principle of this experiment is widely used in a variety of circuit and electric appliances. You can easily come across it in your every day life. One typical example is when you press a certain key of your phone, the backlight will be on.

Project 7: Active buzzer

Introduction

Active buzzer is widely used on computer, printer, alarm, electronic toy, telephone, timer etc as a sound making element. It has an inner vibration source. Simply connect it with 5V power supply, it can buzz continuously. 

Hardware Required
1. Buzzer*1
2. Key *1
3. Breadboard*1
4. Breadboard jumper wires*several

Connection for UNO R3

Connection for 2560 R3

When connecting the circuit, pay attention to the positive & the negative poles of the buzzer. In the photo, you can see there are red and black lines. When the circuit is finished, you can begin programming.

Sample Code

Program is simple. You control the buzzer by outputting high/low level. 

//////////////////////////////////////////////////////////
int buzzer=8;// initialize digital IO pin that controls the buzzer
void setup() 
{ 
  pinMode(buzzer,OUTPUT);// set pin mode as “output”
} 
void loop() 
{
digitalWrite(buzzer, HIGH); // produce sound
}
//////////////////////////////////////////////////////////

Result

After downloading the program, the buzzer experiment is completed. You can see the buzzer is ringing.

Project 8: Passive Buzzer

Introduction

We can use Arduino to make many interactive works of which the most commonly used is acoustic-optic display. All the previous experiment has something to do with LED. However, the circuit in this experiment can produce sound. Normally, the experiment is done with a buzzer or a speaker while buzzer is simpler and easier to use. The buzzer we introduced here is a passive buzzer. It cannot be actuated by itself, but by external pulse frequencies. Different frequencies produce different sounds. We can use Arduino to code the melody of a song, which is actually quite fun and simple.

Hardware Required
1.Passive buzzer*1
2. Key *1
3. Breadboard*1
4. Breadboard jumper wires* several

Connection for UNO R3

Connection for 2560 R3

Sample Code

//////////////////////////////////////////////////////////
int buzzer=8;// select digital IO pin for the buzzer
void setup() 
{ 
pinMode(buzzer,OUTPUT);// set digital IO pin pattern, OUTPUT to be output 
} 
void loop() 
{ unsigned char i,j;//define variable
while(1) 
{ for(i=0;i<80;i++)// output a frequency sound
{ digitalWrite(buzzer,HIGH);// sound
delay(1);//delay1ms 
digitalWrite(buzzer,LOW);//not sound
delay(1);//ms delay 
} 
for(i=0;i<100;i++)// output a frequency sound
{ digitalWrite(buzzer,HIGH);// sound
digitalWrite(buzzer,LOW);//not sound
delay(2);//2ms delay 
}} } 
//////////////////////////////////////////////////////////

Result

After downloading the program, buzzer experiment is finished.

Project 9: RGB LED

Introduction

Tricolor principle to display various colors
PWM controlling ports to display full color
Can be driven directly by Arduino PWM interfaces

Hardware Required
Arduino controller × 1
USB cable × 1
Full-color LED module × 1

Connection for UNO R3

Connection for 2560 R3

Sample Code

//////////////////////////////////////////////////////////
int redpin = 11; //select the pin for the red LED
int bluepin =10; // select the pin for the blue LED
int greenpin =9;// select the pin for the green LED

int val;

void setup() {
  pinMode(redpin, OUTPUT);
  pinMode(bluepin, OUTPUT);
  pinMode(greenpin, OUTPUT);
  Serial.begin(9600);
}

void loop() 
{
for(val=255; val>0; val--)
  {
   analogWrite(11, val);
   analogWrite(10, 255-val);
   analogWrite(9, 128-val);
   delay(1); 
  }
for(val=0; val<255; val++)
  {
   analogWrite(11, val);
   analogWrite(10, 255-val);
   analogWrite(9, 128-val);
   delay(1); 
  }
 Serial.println(val, DEC);
}
//////////////////////////////////////////////////////////

Result

Directly copy the above code into arduino IDE, and click upload , wait a few seconds, you can see a full-color LED.

Project 10: Photo resistor

Introduction

After completing all the previous experiments, we acquired some basic understanding and knowledge about Arduino application. We have learned digital input and output, analog input and PWM. Now, we can begin the learning of sensors applications. Photo resistor (Photovaristor) is a resistor whose resistance varies according to different incident light strength. It's made based on the photoelectric effect of semiconductor. If the incident light is intense, its resistance reduces; if the incident light is weak, the resistance increases. Photovaristor is commonly applied in the measurement of light, light control and photovoltaic conversion (convert the change of light into the change of electricity). Photo resistor is also being widely applied to various light control circuit, such as light control and adjustment, optical switches etc.

We will start with a relatively simple experiment regarding photovaristor application. Photovaristor is an element that changes its resistance as light strenth changes. So we will need to read the analog values. We can refer to the PWM experiment, replacing the potentiometer with photovaristor. When there is change in light strength, there will be corresponding change on the LED.

Hardware Required
Photo resistor*1
Red M5 LED*1
10KΩresistor*1
220Ωresistor*1
Bread board*1
Bread board jumper wires*several

Connection for UNO R3

Connection for 2560 R3

Sample Code

After the connection, let's begin the program compiling. The program is similar to the one of PWM. For change detail, please refer to the sample program below. 

//////////////////////////////////////////////////////////
int potpin=0;// initialize analog pin 0, connected with photovaristor
int ledpin=11;// initialize digital pin 11, output regulating the brightness of LED
int val=0;// initialize variable va
void setup()
{
pinMode(ledpin,OUTPUT);// set digital pin 11 as “output”
Serial.begin(9600);// set baud rate at “9600”
}
void loop()
{
val=analogRead(potpin);// read the analog value of the sensor and assign it to val
Serial.println(val);// display the value of val
analogWrite(ledpin,val);// turn on the LED and set up brightness（maximum output value 255）
delay(10);// wait for 0.01 
}
//////////////////////////////////////////////////////////

Result

After downloading the program, you can change the light strength around the photovaristor and see corresponding brightness change of the LED. Photovaristors has various applications in our everyday life. You can make other interesting interactive projects base on this one.

Project 11: Flame Sensor

Introduction
Flame sensor (Infrared receiving triode) is specially used on robots to find the fire source. This sensor is of high sensitivity to flame. Below is a photo of it.

Working principle
Flame sensor is made based on the principle that infrared ray is highly sensitive to flame. It has a specially designed infrared receiving tube to detect fire, and then convert the flame brightness to fluctuating level signal. The signals are then input into the central processor and be dealt with accordingly.

Sensor connection
The shorter lead of the receiving triode is for negative, the other one for positive. Connect negative to 5V pin, positive to resistor; connect the other end of the resistor to GND, connect one end of a jumper wire to a clip which is electrically connected to sensor positive, the other end to analog pin. As shown below:

Hardware Required
1. Flame sensor *1
2. Buzzer *1
3. 10K resistor x1
4. Breadboard jumper wires: several

Experiment connection
1）Connecting buzzer:
Connect the controller board, prototype board, breadboard and USB cable according to the Arduino tutorial. Connect the buzzer to digital pin 8.

2）Connecting flame sensor:
Connect the sensor to analog pin 0.

Connection for UNO R3

Connection for 2560 R3

Experiment principle
When it's approaching a fire, the voltage value the analog port reads differs. If you use a multimeter, you can know when there is no fire approaching, the voltage it reads is around 0.3V; when there is fire approaching, the voltage it reads is around 1.0V, tthe nearer the fire, the higher the voltage. So in the beginning of the program, you can initialize voltage value i (no fire value); Then, continuously read the analog voltage value j and obtain difference value k=j-i; compare k with 0.6V (123 in binary) to determine whether or not there is a fire approaching; if yes, the buzzer will buzz.

Sample Code

////////////////////////////////////////////////////////////////
int flame=0;// select analog pin 0 for the sensor
 int Beep=9;// select digital pin 9 for the buzzer
 int val=0;// initialize variable
 void setup() 
{
  pinMode(Beep,OUTPUT);// set LED pin as “output”
 pinMode(flame,INPUT);// set buzzer pin as “input”
 Serial.begin(9600);// set baud rate at “9600”
 } 
void loop() 
{ 
  val=analogRead(flame);// read the analog value of the sensor 
  Serial.println(val);// output and display the analog value
  if(val>=600)// when the analog value is larger than 600, the buzzer will buzz
  {  
   digitalWrite(Beep,HIGH); 
   }else 
   {  
     digitalWrite(Beep,LOW); 
    }
   delay(500); 
}
////////////////////////////////////////////////////////////////

Result

This program can simulate an alarm when there is a fire. Everything is normal when there is no fire; when there is, the alarm will be set off immediately.

Project 12: LM35 temperature sensor

Introduction
LM35 is a common and easy-to-use temperature sensor. It does not require other hardware. You just need an analog port to make it work. The difficulty lies in compiling the code to convert the analog value it reads to celsius temperature.

Hardware Required
1. LM35*1
2. Breadboard*1
3. Breadboard jumper wires*several

Connection for UNO R3

Connection for 2560 R3

Sample Code

//////////////////////////////////////////////////////////
int potPin = 0; // initialize analog pin 0 for LM35 temperature sensor
void setup()
{
Serial.begin(9600);// set baud rate at”9600”
}
void loop()
{
int val;// define variable
int dat;// define variable
val=analogRead(0);// read the analog value of the sensor and assign it to val
dat=(125*val)>>8;// temperature calculation formula
Serial.print("Tep:");// output and display characters beginning with Tep
Serial.print(dat);// output and display value of dat
Serial.println("C");// display “C” characters
delay(500);// wait for 0.5 second
}
//////////////////////////////////////////////////////////

Result

After downloading the program, you can open the monitoring window to see current temperature.  

 

Project 13: Tilt switch

Introduction
Tilt switch controlling the ON and OFF of LED

Hardware Required
1. Ball switch*1 2. Led *1
3. 220Ω resistor*1
4. 10kΩ resistor*1
5. Breadboard jumper wires:several

Connection for UNO R3

Connection for 2560 R3

Connect the controller board, shield, breadboard and USB cable according to Arduino tutorial. Connect the LED to digital pin 8, ball switch to analog pin 5. Experiment principle
When one end of the switch is below horizontal position, the switch is on. The voltage of the analog port is about 5V (1023 in binary). The LED will be on. When the other end of the switch is below horizontal position, the switch is off. The voltage of the analog port is about 0V (0 in binary). The LED will be off. In the program, we determine whether the switch is on or off according to the voltage value of the analog port, whether it's above 2.5V (512 in binary) or not.

Sample Code

////////////////////////////////////////////////////////// 
void setup() 
{ 
  pinMode(8,OUTPUT);// set digital pin 8 as “output” 
} 
void loop() 
{ 
int i;// define variable i 
while(1) 
{ 
  i=analogRead(5);// read the voltage value of analog pin 5 
  if(i>512)// if larger that 512（2.5V） 
  { 
    digitalWrite(8,LOW);// turn on LED 
  } 
  else// otherwise 
  { 
    digitalWrite(8,HIGH);// turn off LED 
  } 
 } 
}
//////////////////////////////////////////////////////////

Result

Hold the breadboard with your hand. Tilt it to a certain extent, the LED will be on. If there is no tilt, the LED will be off. The principle of this experiment can be applied to relay control. Experiment completed. Thank you!

 

Project 14: IR remote control

Introduction
What is an infrared receiver? The signal from the infrared remote controller is a series of binary pulse code. To avoid interference from other infrared signals during the wireless transmission, the signal is pre-modulate at a specific carrier frequency and then send out by a infrared emission diode. The infrared receiving device needs to filter out other wave and receive signal at that specific frequency and modulate it back to binary pulse code, known as demodulation. Working principal The built-in receiver converts the light signal it received from the sender into feeble electrical signal. The signal will be amplified by the IC amplifier.
After automatic gain control, band-pass filtering, demodulation, wave shaping, it returns to the original code. The code is then input to the code identification circuit by the receiver's signal output pin.
The pin and the connection of the infrared receiving head
Pin and wiring of infrared receiver

Infrared receiver has 3 pins.
When you use it, connect VOUT to analog pin, GND to GND, VCC to +5V.
2. Infrared remote control experiment

Hardware Required
Infrared remote controller x1
Infrared receiver x1
LED x6
220Ω resistor x6
Multi-color breadboard wires x several

Connection
First, connect the controller board; then connect the infrared receiver as the above mentioned, connect VOUT to digital pin 11, connect the LEDs with resistors and connect the resisters to pin 2,3,4,5,6,7. 

Connection for UNO R3

Connection for 2560 R3

Experiment principle

If you want to decode code of a remote controller, you must first know how it's coded. The coding method we use here is NEC protocol. Below is a brief introduction. ·NEC protocol:
Features：
(1) 8 bit address and 8 bit command length
(2) address and command are transmitted twice for reliability
(3) pulse distance modulation
(4) carrier frequency of 38 KHZ 
(5) bit time of 1.125ms or 2.25ms

Protocol is as below:

• Definition of logical 0 and 1 is as below

• Pulse transmitted when button is pressed and immediately released

The picture above shows a typical pulse train of the NEC protocol. With this protocol the LSB is transmitted first. In this case Address $59 and Command $16 is transmitted. A message is started by a 9ms AGC burst, which was used to set the gain of the earlier IR receivers. This AGC burst is then followed by a 4.5ms space, which is then followed by the address and command. Address and Command are transmitted twice. The second time all bits are inverted and can be used for verification of the received message. The total transmission time is constant because every bit is repeated with its inverted length. If you are not interested in this reliability, you can ignore the inverted values, or you can expend the Address and Command to 16 bits each!
• Pulse transmitted when button is pressed and released after a period of time

A command is transmitted only once, even when the key on the remote control remains pressed. Every 110ms a repeat code is transmitted for as long as the key remains down. This repeat code is simply a 9ms AGC pulse followed by a 2.25ms space and a 560µs burst. 

·Repeat pulse

Note: when the pulse enters the integrated receiver, there will be decoding, signal amplifying and wave shaping process. So you need to make sure the level  of the output is just the opposite from that of the signal sending end. That is when there is no infrared signal, the output end is in high level; when there is infrared signal, the output end is in low level. You can see the pulse of the receiving end in the oscilloscope. Try to better understand the program base on what you see.

Sample Code

//////////////////////////////////////////////////////////
#include <IRremote.h>
int RECV_PIN = 11;
int LED1 = 2;
int LED2 = 3;
int LED3 = 4;
int LED4 = 5;
int LED5 = 6;
int LED6 = 7;
long on1  = 0x00FFA25D;
long off1 = 0x00FFE01F;
long on2 = 0x00FF629D;
long off2 = 0x00FFA857;
long on3 = 0x00FFE21D;
long off3 = 0x00FF906F;
long on4 = 0x00FF22DD;
long off4 = 0x00FF6897;
long on5 = 0x00FF02FD;
long off5 = 0x00FF9867;
long on6 = 0x00FFC23D;
long off6 = 0x00FFB047;
IRrecv irrecv(RECV_PIN);
decode_results results;
// Dumps out the decode_results structure.
// Call this after IRrecv::decode()
// void * to work around compiler issue
//void dump(void *v) {
//  decode_results *results = (decode_results *)v
void dump(decode_results *results) {
  int count = results->rawlen;
  if (results->decode_type == UNKNOWN) 
    {
     Serial.println("Could not decode message");
    } 
  else 
   {
    if (results->decode_type == NEC) 
      {
       Serial.print("Decoded NEC: ");
      } 
    else if (results->decode_type == SONY) 
      {
       Serial.print("Decoded SONY: ");
      } 
    else if (results->decode_type == RC5) 
      {
       Serial.print("Decoded RC5: ");
      } 
    else if (results->decode_type == RC6) 
      {
       Serial.print("Decoded RC6: ");
      }
     Serial.print(results->value, HEX);
     Serial.print(" (");
     Serial.print(results->bits, DEC);
     Serial.println(" bits)");
   }
     Serial.print("Raw (");
     Serial.print(count, DEC);
     Serial.print("): ");
 for (int i = 0; i < count; i++) 
     {
      if ((i % 2) == 1) {
      Serial.print(results->rawbuf[i]*USECPERTICK, DEC);
     } 
    else  
     {
      Serial.print(-(int)results->rawbuf[i]*USECPERTICK, DEC);
     }
    Serial.print(" ");
     }
      Serial.println("");
     }
void setup()
 {
  pinMode(RECV_PIN, INPUT);   
  pinMode(LED1, OUTPUT);
  pinMode(LED2, OUTPUT);
  pinMode(LED3, OUTPUT);
  pinMode(LED4, OUTPUT);
  pinMode(LED5, OUTPUT);
  pinMode(LED6, OUTPUT);  
  pinMode(13, OUTPUT);
  Serial.begin(9600);
   irrecv.enableIRIn(); // Start the receiver
 }
int on = 0;
unsigned long last = millis();

void loop() 
{
  if (irrecv.decode(&results)) 
   {
    // If it's been at least 1/4 second since the last
    // IR received, toggle the relay
    if (millis() - last > 250) 
      {
       on = !on;
//       digitalWrite(8, on ? HIGH : LOW);
       digitalWrite(13, on ? HIGH : LOW);
       dump(&results);
      }
    if (results.value == on1 )
       digitalWrite(LED1, HIGH);
    if (results.value == off1 )
       digitalWrite(LED1, LOW); 
    if (results.value == on2 )
       digitalWrite(LED2, HIGH);
    if (results.value == off2 )
       digitalWrite(LED2, LOW); 
    if (results.value == on3 )
       digitalWrite(LED3, HIGH);
    if (results.value == off3 )
       digitalWrite(LED3, LOW);
    if (results.value == on4 )
       digitalWrite(LED4, HIGH);
    if (results.value == off4 )
       digitalWrite(LED4, LOW); 
    if (results.value == on5 )
       digitalWrite(LED5, HIGH);
    if (results.value == off5 )
       digitalWrite(LED5, LOW); 
    if (results.value == on6 )
       digitalWrite(LED6, HIGH);
    if (results.value == off6 )
       digitalWrite(LED6, LOW);        
    last = millis();      
irrecv.resume(); // Receive the next value
  }
}
//////////////////////////////////////////////////////////

Program function Decode the coded pulse signal emitted by the remote controller; execute corresponding action according to the results of the decoding. In this way, you will be able to control your device with remote controller. 

Result

Note：add IRremote folder into installation directory \Arduino\compiler libraries, or you will not be able to compile. Infrared remote library :https://github.com/z3t0/Arduino-IRremote

Project 15: Analog value reading

Introduction
Introduction In this experiment, we will begin the learning of analog I/O interfaces. On an Arduino, there are 6 analog interfaces numbered from 0 to 5. These 6 interfaces can also be used as digital ones numbered as 14-19. After a brief introduction, let's begin our project. Potentiometer used here is a typical output component of analog value that is familiar to us. 

Hardware Required
Potentiometer *1
Breadboard*1
Breadboard jumper wires * several

Connection
In this experiment, we will convert the resistance value of the potentiometer to analog ones and display it on the screen. This is an application we need to master well for our future experiments. Connection circuit as below: 

Connection for UNO R3

Connection for 2560 R3

We use the analog interface 0.
The analog interface we use here is interface 0.

Sample Code

The program compiling is simple. An analogRead () Statement can read the value of the interface. The A/D acquisition of Arduino 328 is in 10 bits, so the value it reads is among 0 to 1023. One difficulty in this project is to display the value on the screen, which is actually easy to learn. First, we need to set the baud rate in voidsetup (). Displaying the value is a communication between Arduino and PC, so the baud rate of the Arduino should match the the one in the PC's software set up. Otherwise, the display will be messy codes or no display at all. In the lower right corner of the Arduino software monitor window, there is a button for baud rate set up. The set up here needs to match the one in the program. The statement in the program is Serial.begin(); enclosed is the baud rate value, followed by statement for displaying. You can either use Serial.print() or Serial.println() statement. 

//////////////////////////////////////////////////////////
int potpin=0;// initialize analog pin 0
int ledpin=13;// initialize digital pin 13
int val=0;// define val, assign initial value 0
void setup()
{
pinMode(ledpin,OUTPUT);// set digital pin as “output”
Serial.begin(9600);// set baud rate at 9600
}
void loop()
{
digitalWrite(ledpin,HIGH);// turn on the LED on pin 13
delay(50);// wait for 0.05 second
digitalWrite(ledpin,LOW);// turn off the LED on pin 13
delay(50);// wait for 0.05 second
val=analogRead(potpin);// read the analog value of analog pin 0, and assign it to val 
Serial.println(val);// display val’s value
}
//////////////////////////////////////////////////////////

Result
The sample program uses the built-in LED connected to pin 13. Each time the device reads a value, the LED blinks. Below is the analog value it reads.

When you rotate the potentiometer knob, you can see the displayed value changes. The reading of analog value is a very common function since most sensors output analog value. After calculation, we can have the corresponding value we need. The experiment is now completed, thank you.

Project 16: 74HC595

Introduction
To put it simply, 74HC595 is a combination of 8-digit shifting register, memorizer and equipped with tri-state output. Here, we use it to control 8 LEDs. You may wonder why use a 74HC595 to control LED? Well, think about how many I/O it takes for an Arduino to control 8 LEDs? Yes, 8. For an Arduino 168, it has only 20 I/O including analog ports. So, to save port resources, we use 74HC595 to reduce the number of ports it needs. Using 74HC595 enables us to use 3 digital I/O port to control 8 LEDs!

Hardware Required
74HC595 chip*1
Red M5 LED*4
Green M5 LED*4
220Ω resistor*8
Breadboard*1
Breadboard jumper wires*several
Note: for pin 13 OE port of 74HC595, it needs to connect to GND

Connection for UNO R3

Connection for 2560 R3

The circuit may seem complicated, but once you give it a good look, you will find it easy!

Sample Code

The program compiling is simple. An analogRead () Statement can read the value of the interface. The A/D acquisition of Arduino 328 is in 10 bits, so the value it reads is among 0 to 1023. One difficulty in this project is to display the value on the screen, which is actually easy to learn. First, we need to set the baud rate in voidsetup (). Displaying the value is a communication between Arduino and PC, so the baud rate of the Arduino should match the the one in the PC's software set up. Otherwise, the display will be messy codes or no display at all. In the lower right corner of the Arduino software monitor window, there is a button for baud rate set up. The set up here needs to match the one in the program. The statement in the program is Serial.begin(); enclosed is the baud rate value, followed by statement for displaying. You can either use Serial.print() or Serial.println() statement. 

//////////////////////////////////////////////////////////
int data = 2;// set pin 14 of 74HC595as data input pin SI 
int clock = 5;// set pin 11 of 74hc595 as clock pin SCK
int latch = 4;// set pin 12 of 74hc595 as output latch RCK 
int ledState = 0;
const int ON = HIGH;
const int OFF = LOW;
void setup()
{
pinMode(data, OUTPUT);
pinMode(clock, OUTPUT);
pinMode(latch, OUTPUT);
}
void loop()
{
for(int i = 0; i < 256; i++)
{
updateLEDs(i);
delay(500);
}
//////////////////////////////////////////////////////////

Result
After downloading the program, you can see 8 LEDs displaying 8-bit binary number.

Project 17: 1-digit LED segment display

Introduction
LED segment displays are common for displaying numerical information. It's widely applied on displays of electromagnetic oven, full automatic washing machine, water temperature display, electronic clock etc. It is necessary that we learn how it works.

LED segment display is a semiconductor light-emitting device. Its basic unit is a light-emitting diode (LED). LED segment display can be divided into 7-segment display and 8-segment display according to the number of segments. 8-segment display has one more LED unit ( for decimal point display) than 7-segment one. In this experiment, we use a 8-segment display. According to the wiring method of LED units, LED segment displays can be divided into display with common anode and display with common cathode. Common anode display refers to the one that combine all the anodes of LED units into one common anode (COM).

For the common anode display, connect the common anode (COM) to +5V. When the cathode level of a certain segment is low, the segment is on; when the cathode level of a certain segment is high, the segment is off. For the common cathode display, connect the common cathode (COM) to GND. When the anode level of a certain segment is high, the segment is on; when the anode level of a certain segment is low, the segment is off.

Common cathode 7-segment display

Each segment of the display consists of an LED.  So when you use it, you also need use a current-limiting resistor. Otherwise, LED will be burnt out. In this experiment, we use a common cathode display. As we mentioned above, for common cathode display, connect the common cathode (COM) to GND. When the anode level of a certain segment is high, the segment is on; when the anode level of a certain segment is low, the segment is off.

Hardware Required
Eight-segment display*1
220Ω resistor*8
Breadboard*1
Breadboard jumper wires*several

Connection for UNO R3

Connection for 2560 R3

Sample Code

There are seven segments for numerical display, one for decimal point display. Corresponding segments will be turned on when displaying certain numbers. For example, when displaying number 1, b and c segments will be turned on. We compile a subprogram for each number, and compile the main program to display one number every 2 seconds, cycling display number 0 ~ 9. The displaying time for each number is subject to the delay time, the longer the delay time, the longer the displaying time. 

//////////////////////////////////////////////////////////
// set the IO pin for each segment
int a=7;// set digital pin 7 for segment a
int b=6;// set digital pin 6 for segment b
int c=5;// set digital pin 5 for segment c
int d=10;// set digital pin 10 for segment d
int e=11;// set digital pin 11 for segment e
int f=8;// set digital pin 8 for segment f
int g=9;// set digital pin 9 for segment g
int dp=4;// set digital pin 4 for segment dp
void digital_0(void) // display number 5
{
unsigned char j;
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,LOW);
digitalWrite(dp,LOW);
}
void digital_1(void) // display number 1
{
unsigned char j;
digitalWrite(c,HIGH);// set level as “high” for pin 5, turn on segment c
digitalWrite(b,HIGH);// turn on segment b
for(j=7;j<=11;j++)// turn off other segments
digitalWrite(j,LOW);
digitalWrite(dp,LOW);// turn off segment dp
}
void digital_2(void) // display number 2
{
unsigned char j;
digitalWrite(b,HIGH);
digitalWrite(a,HIGH);
for(j=9;j<=11;j++)
digitalWrite(j,HIGH);
digitalWrite(dp,LOW);
digitalWrite(c,LOW);
digitalWrite(f,LOW);
}
void digital_3(void) // display number 3
{digitalWrite(g,HIGH);
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(dp,LOW);
digitalWrite(f,LOW);
digitalWrite(e,LOW);
}
void digital_4(void) // display number 4
{digitalWrite(c,HIGH);
digitalWrite(b,HIGH);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
digitalWrite(dp,LOW);
digitalWrite(a,LOW);
digitalWrite(e,LOW);
digitalWrite(d,LOW);
}
void digital_5(void) // display number 5
{
unsigned char j;
digitalWrite(a,HIGH);
digitalWrite(b, LOW);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e, LOW);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
digitalWrite(dp,LOW);
}
void digital_6(void) // display number 6
{
unsigned char j;
for(j=7;j<=11;j++)
digitalWrite(j,HIGH);
digitalWrite(c,HIGH);
digitalWrite(dp,LOW);
digitalWrite(b,LOW);
}
void digital_7(void) // display number 7
{
unsigned char j;
for(j=5;j<=7;j++)
digitalWrite(j,HIGH);
digitalWrite(dp,LOW);
for(j=8;j<=11;j++)
digitalWrite(j,LOW);
}
void digital_8(void) // display number 8
{
unsigned char j;
for(j=5;j<=11;j++)
digitalWrite(j,HIGH);
digitalWrite(dp,LOW);
}
void digital_9(void) // display number 5
{
unsigned char j;
digitalWrite(a,HIGH);
digitalWrite(b,HIGH);
digitalWrite(c,HIGH);
digitalWrite(d,HIGH);
digitalWrite(e, LOW);
digitalWrite(f,HIGH);
digitalWrite(g,HIGH);
digitalWrite(dp,LOW);
}
void setup()
{
int i;// set variable
for(i=4;i<=11;i++)
pinMode(i,OUTPUT);// set pin 4-11as “output”
}
void loop()
{
while(1)
{
digital_0();// display number 0
delay(1000);// wait for 1s
digital_1();// display number 1
delay(1000);// wait for 1s
digital_2();// display number 2
delay(1000); // wait for 1s
digital_3();// display number 3
delay(1000); // wait for 1s
digital_4();// display number 4
delay(1000); // wait for 1s
digital_5();// display number 5
delay(1000); // wait for 1s
digital_6();// display number 6
delay(1000); // wait for 1s
digital_7();// display number 7
delay(1000); // wait for 1s
digital_8();// display number 8
delay(1000); // wait for 1s
digital_9();// display number 9
delay(1000); // wait for 1s
}
}
//////////////////////////////////////////////////////////

Result
LED segment display displays number 0 to 9.

Project 18: 4-digit LED segment display

Introduction
In this experiment, we use an Arduino to drive a common anode, 4-digit, 7-segment LED display. For LED display, current-limiting resistors are indispensable. There are two wiring method for Current-limiting resistor. One is to connect one resistor for each anode, 4 in totals for d1-d4 anode. An advantage for this method is that it requires fewer resistors, only 4. But it cannot maintain consistent brightness, 1 the brightest, 8, the least bright. Another method is to connect one resistor to each pin. It guarantees consistent brightness, but requires more resistors. In this experiment, we use 8 220Ω resistors (we use 220Ω resistors because no 100Ω resistor available. If you use 100Ω, the displaying will be brighter).

Connection

For 4-digit displays, there are 12 pins in total. When you place the decimal point downward , the pin on the lower left part is refer to as 1, the upper left part 12. 

Manual for LED segment display

Connection for UNO R3

Connection for 2560 R3

Sample Code

There are seven segments for numerical display, one for decimal point display. Corresponding segments will be turned on when displaying certain numbers. For example, when displaying number 1, b and c segments will be turned on. We compile a subprogram for each number, and compile the main program to display one number every 2 seconds, cycling display number 0 ~ 9. The displaying time for each number is subject to the delay time, the longer the delay time, the longer the displaying time. 

//////////////////////////////////////////////////////////
// display 1234 
	// select pin for cathode
	int a = 1;
	int b = 2;
	int c = 3;
	int d = 4;
	int e = 5;
	int f = 6;
	int g = 7;
	int dp = 8;
	// select pin for anode
	int d4 = 9;
	int d3 = 10;
	int d2 = 11;
	int d1 = 12;
	// set variable
	long n = 1230;
	int x = 100;
	int del = 55;  // fine adjustment for clock
	 
	void setup()
	{
	  pinMode(d1, OUTPUT);
	  pinMode(d2, OUTPUT);
	  pinMode(d3, OUTPUT);
	  pinMode(d4, OUTPUT);
	  pinMode(a, OUTPUT);
	  pinMode(b, OUTPUT);
	  pinMode(c, OUTPUT);
	  pinMode(d, OUTPUT);
	  pinMode(e, OUTPUT);
	  pinMode(f, OUTPUT);
	  pinMode(g, OUTPUT);
	  pinMode(dp, OUTPUT);
	}
/////////////////////////////////////////////////////////////
void loop()
{
 Display(1, 1);
 Display(2, 2);
 Display(3, 3);
 Display(4, 4);

}
///////////////////////////////////////////////////////////////
void WeiXuan(unsigned char n)//
{
    switch(n)
     {
	case 1: 
	  digitalWrite(d1,LOW);
 	  digitalWrite(d2, HIGH);
	  digitalWrite(d3, HIGH);
	  digitalWrite(d4, HIGH);   
	 break;
	 case 2: 
	  digitalWrite(d1, HIGH);
 	  digitalWrite(d2, LOW);
	  digitalWrite(d3, HIGH);
	  digitalWrite(d4, HIGH); 
	    break;
	  case 3: 
	    digitalWrite(d1,HIGH);
 	   digitalWrite(d2, HIGH);
	   digitalWrite(d3, LOW);
	   digitalWrite(d4, HIGH); 
	    break;
	  case 4: 
	   digitalWrite(d1, HIGH);
 	   digitalWrite(d2, HIGH);
	   digitalWrite(d3, HIGH);
	   digitalWrite(d4, LOW); 
	    break;
        default :
           digitalWrite(d1, HIGH);
	   digitalWrite(d2, HIGH);
	   digitalWrite(d3, HIGH);
	   digitalWrite(d4, HIGH);
        break;
	  }
}
void Num_0()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, LOW);
  digitalWrite(dp,LOW);
}
void Num_1()
{
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,LOW);
}
void Num_2()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_3()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_4()
{
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_5()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_6()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_7()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,LOW);
}
void Num_8()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Num_9()
{
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
  digitalWrite(dp,LOW);
}
void Clear()  // clear the screen
{
  digitalWrite(a, LOW);
  digitalWrite(b, LOW);
  digitalWrite(c, LOW);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
  digitalWrite(dp,LOW);
}
void pickNumber(unsigned char n)// select number
{
  switch(n)
  {
   case 0:Num_0();
   break;
   case 1:Num_1();
   break;
   case 2:Num_2();
   break;
   case 3:Num_3();
   break;
   case 4:Num_4();
   break;
   case 5:Num_5();
   break;
   case 6:Num_6();
   break;
   case 7:Num_7();
   break;
   case 8:Num_8();
   break;
   case 9:Num_9();
   break;
   default:Clear();
   break; 
  }
}
void Display(unsigned char x, unsigned char Number)//  take x as coordinate and display number
{
  WeiXuan(x);
  pickNumber(Number);
 delay(1);
 Clear() ; // clear the screen
}
//////////////////////////////////////////////////////////

Result
Download the above code to the controller board and see the result. The experiment result displays 1234 on the display. Note: if it’s not displaying correctly, check the wiring. Thank you.

Project 19: 8*8 LED matrix

Introduction
With low-voltage scanning, LED dot-matrix displays have advantages such as power saving, long service life, low cost, high brightness, wide angle of view, long visual range, waterproof, and numerous specifications. LED dot-matrix displays can meet the needs of different applications and thus have a broad development prospect. This time, we will conduct an LED dot-matrix experiment to experience its charm firsthand.

Hardware required
1 * Uno board
1 * 8*8 dot-matrix
8 * Resistor (220Ω)
1 * Breadboard
2 * 74HC595
1 * USB cable
Jumper wires

Circuit connection
The external view of a dot-matrix is shown as follows:

The display principle of the 8*8 dot-matrix:
The 8*8 dot-matrix is made up of sixty-four LEDs, and each LED is placed at the cross point of a row and a column. When the electrical level of a certain row is 1 and the electrical level of acertain column is 0, the corresponding LED will light up. If you want to light the LED on the first dot, you should set pin 9 to high level and pin 13 to low level. If you want to light LEDs on the first row, you should set pin 9 to high level and pins 13, 3, 4, 10, 6, 11, 15 and 16 to low level. If you want to light the LEDs on the first column, set pin 13 to low level and pins 9, 14, 8, 12, 1, 7, 2 and 5 to high level.

The internal view of a dot-matrix is shown as follows:

The principle of 74HC595 has been previously illustrated. One chip is used to control the rows of the dot-matrix while the other chip is used to control the columns.

Connect circuit as shown in the following diagram:

Connection for UNO R3

Connection for 2560 R3

Sample Code for displaying “0”

//////////////////////////////////////////////////////////
// set an array to store character of “0”
unsigned char Text[]={0x00,0x1c,0x22,0x22,0x22,0x22,0x22,0x1c};
void Draw_point(unsigned char x,unsigned char y)// point drawing function
{ clear_();
   digitalWrite(x+2, HIGH);
   digitalWrite(y+10, LOW);
   delay(1);
}
void show_num(void)// display function, call point drawing function
{
  unsigned char i,j,data;
  for(i=0;i<8;i++)
  {
    data=Text[i];
    for(j=0;j<8;j++)
    {
      if(data & 0x01)Draw_point(j,i);
      data>>=1;
    }  
  }
}
void setup(){ 
int i = 0 ; 
for(i=2;i<18;i++) 
 { 
   pinMode(i, OUTPUT); 
  }  
  clear_(); 
}
void loop()
{ show_num();    
} 
void clear_(void)// clear screen
{for(int i=2;i<10;i++)
  digitalWrite(i, LOW);
  for(int i=0;i<8;i++)
  digitalWrite(i+10, HIGH);
}

//////////////////////////////////////////////////////////

Result
Burn the program into Uno board The dot-matrix will display 0.

Project 20: 1602 LCD

Introduction
In this experiment, we use an Arduino to drive the 1602 LCD. 1602 LCD has wide applications. In the beginning, 1602 LCD uses a HD44780 controller. Now, almost all 1602 LCD module uses a compatible IC, so their features are basically the same. 

1602LCD main parameters:

• Display capacity: 16 × 2 characters.
• Chip operating voltage: 4.5 ~ 5.5V.
• Working current: 2.0mA (5.0V).
• Optimum working voltage of the module is 5.0V.
• Character size: 2.95 * 4.35 (W * H) mm.

Pin description of 1602 LCD

No.	Mark	Pin description	No.	Mark	Pin description
1	VSS	Power GND	9	D2	Date I/O

Hardware required
1 * Uno board
1 * 8*8 dot-matrix
8 * Resistor (220Ω)
1 * Breadboard
2 * 74HC595
1 * USB cable
Jumper wires

Circuit connection
The external view of a dot-matrix is shown as follows:

The display principle of the 8*8 dot-matrix:
The 8*8 dot-matrix is made up of sixty-four LEDs, and each LED is placed at the cross point of a row and a column. When the electrical level of a certain row is 1 and the electrical level of acertain column is 0, the corresponding LED will light up. If you want to light the LED on the first dot, you should set pin 9 to high level and pin 13 to low level. If you want to light LEDs on the first row, you should set pin 9 to high level and pins 13, 3, 4, 10, 6, 11, 15 and 16 to low level. If you want to light the LEDs on the first column, set pin 13 to low level and pins 9, 14, 8, 12, 1, 7, 2 and 5 to high level.

The internal view of a dot-matrix is shown as follows:

The principle of 74HC595 has been previously illustrated. One chip is used to control the rows of the dot-matrix while the other chip is used to control the columns.

Connect circuit as shown in the following diagram:

Connection for UNO R3

Connection for 2560 R3

Sample Code for displaying “0”

//////////////////////////////////////////////////////////
// set an array to store character of “0”
unsigned char Text[]={0x00,0x1c,0x22,0x22,0x22,0x22,0x22,0x1c};
void Draw_point(unsigned char x,unsigned char y)// point drawing function
{ clear_();
   digitalWrite(x+2, HIGH);
   digitalWrite(y+10, LOW);
   delay(1);
}
void show_num(void)// display function, call point drawing function
{
  unsigned char i,j,data;
  for(i=0;i<8;i++)
  {
    data=Text[i];
    for(j=0;j<8;j++)
    {
      if(data & 0x01)Draw_point(j,i);
      data>>=1;
    }  
  }
}
void setup(){ 
int i = 0 ; 
for(i=2;i<18;i++) 
 { 
   pinMode(i, OUTPUT); 
  }  
  clear_(); 
}
void loop()
{ show_num();    
} 
void clear_(void)// clear screen
{for(int i=2;i<10;i++)
  digitalWrite(i, LOW);
  for(int i=0;i<8;i++)
  digitalWrite(i+10, HIGH);
}

//////////////////////////////////////////////////////////

Result
Burn the program into Uno board The dot-matrix will display 0.