Lesson 24 – Temperature Alarm


As a final lesson in this kit, this is relatively more complicated for it involves three different modules. But don’t worry. I believe you will also find it simple as you have learned so much in previous lessons. In this lesson, when the temperature reaches a certain value, here 25℃, the alarm will go off.

Hardware Required

  1. EASY plug controller Board *1
  2. EASY plug cable *3
  3. USB cable *1
  4. EASY plug Digital White LED Module *1
  5. EASY plug Active Buzzer module *1
  6. EASY plug LM35 Temperature Sensor *1

Connection Diagram

Now, connect the LED module to the D11 port of the controller board, buzzer module to D10, and LM35 temperature sensor to A0 port using the EASY plug cables.



Arduino IDE – Open up the Arduino IDE and copy the code provided below. Then connect the board to your PC using the USB cable and click upload to upload it to your board.


int buzzPin = 10; 
int ledpin= 11;
void setup()
   Serial.begin(9600);// Set Baud Rate to 9600 bps
   pinMode(ledpin,OUTPUT);// define LED as output 
   pinMode(buzzPin,OUTPUT);// define buzzer as output 
void loop()
{  int val;
   int dat;
   val=analogRead(0);// Connect LM35 on Analog 0
   dat=(500 * val) /1024;
   Serial.print("Temp:"); // Display the temperature on Serial monitor
    if (dat>25) // when temperature is higher than 25℃, LED will be turned on, and buzzer will ring
  digitalWrite(buzzPin, HIGH);  // turn buzzer ON
  digitalWrite(ledpin, HIGH);  // turn LED ON
   digitalWrite(buzzPin, LOW);  // turn buzzer OFF
   digitalWrite(ledpin, LOW); // turn LED OFF


Open serial monitor, you can see the current temperature. When the temperature goes higher that 25℃ (you can blow air with your month to the module to make the temperature go higher or you can change the 25 here if (dat>25) to a lower value ), the LED will be turned on, and the buzzer will ring.


This development track requires an investment a bit of hardware. See below for details –

  1. You will need to download and install the Arduino development IDE or the mixly block based graphical programming interface. The approach to installation, configuration, setup of the Arduino IDE is covered in our tutorials.
  2. The mixly block based graphical programming interface will allow you to work through the tutorials in the learning track and write the code using a block based graphical programming interface.
  3. You will need to purchase the Easy Plug Starter Learning Kit for Arduino from OzToyLib. The Arduino Advent kit has all the sensors you need to perform the tutorials covered in this development track.
  4. This kit ships with an Arduino Uno. You should be able to perform each of the tutorials in this track using the Arduino board included in the package.
  5. You can also purchase additional Arduino boards i.e. Arduino Mega 2560 from OzToyLib.

The Easy Plug Starter Learning Kit for the Arduino kit has all the sensors you need to perform the tutorials covered in this development track.

About the Easy Plug Super Learning Kit for Arduino

The Easy Plug Starter Learning Kit for the Arduino comes packed with ~30+ different electronic bits (Sensors, LEDs, switches, LCD, servo, etc.) including tutorials to get started. The Easy Plug Starter Learning Kit comes with specially designed easy to use sensors including an easy to use Arduino board. Both the sensors and the Arduino board are design for eas of use eliminating the need to work out how to connect the sensors to the board and get the circuit right. The RJ11 connectors on board the sensors and the Arduino board are meant to simplify construction of the circuit, reducing the potential for connection errors allowing you to focus on design of the code. The Easy Plug Starter kit for the Arduino is especially suited to someone who is just starting out with electronics or the Arduino or even someone who doesn’t necessarily have the expertise available locally to help out with connections. We would recommend this kit to both kids and adults getting started with the STEM learning journey with a focus on electronics and Arduino.

The Arduino advanced study kit walks you through the basics of using the Arduino in a hands-on way. You’ll learn the fundamentals of electronics and working on the Arduino through building several creative projects. The kit includes a selection of the most common and useful electronic components with a book of 22 projects. Starting the basics of electronics, to more complex projects, the kit will get you interacting with the physical world using sensor and actuators. Along with the kit you get access to detailed tutorials and wiring diagrams.

You can purchase the Easy Plug Starter Learning Kit for Arduino from OzToyLib.


About the Arduino UNO

The Arduino UNO is the most used and documented board of the whole Arduino family and very easy to setup, play with. The Arduino UNO is a microcontroller board based on the ATmega328 . The Arduino UNO 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. Here’s a listing of the some of the features of the Arduino UNO –

  1. Microcontroller: ATmega328
  2. Operating Voltage: 5V
  3. Input Voltage (recommended): 7-12V
  4. Input Voltage (limits): 6-20V
  5. Digital I/O Pins: 14 (of which 6 provide PWM output)
  6. Analog Input Pins: 6
  7. DC Current per I/O Pin: 40 mA
  8. DC Current for 3.3V Pin: 50 mA
  9. Flash Memory: 32 KB of which 0.5 KB used by bootloader
  10. SRAM: 2 KB (ATmega328)
  11. EEPROM: 1 KB (ATmega328)
  12. Clock Speed: 16 MHz

Arduino is an open-source, prototyping platform and its simplicity makes it ideal for hobbyists to use as well as professionals. The Arduino UNO 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 Arduino UNO differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega8U2 microcontroller chip programmed as a USB-to-serial converter. “Uno” means one in Italian and is named to mark the upcoming release of Arduino 1.0. The Arduino Uno and version 1.0 will be the reference versions of Arduno, moving forward. The Uno is the latest in a series of USB Arduino boards, and the reference model for the Arduino platform.

You can read more about the Arduino here – www.arduino.cc.