programmed with a microcontroller which will sound the buzzer alarm and control LED according to the temperature reading. Microcontroller is used to control the overall system automatically that reduces the design and control complexity. At first, temperature sensor is sensed temperature from the engine and sent it to the microcontroller. The microcontroller is programmed and temperature is shown in LCD. If the temperature is greater than 69 and less than 80 then LED start blinking and buzzer on/off, LCD display show the temperature. If the condition fails, then the temperature is again checked. If the temperature is greater than 79 then continuous sounds arises and LED switches on and is shown in LCD. Temperature will be shown in this system continuously. Figure 2. Block diagram of the project 3. Components The components of the system are as follows: The circuit is connected to a 6 volt DC power supply. Pin 2,3,4,6,11,12,13 of micro-controller AT mega 8 is connected with LCD via variable resistor. In temperature sensor pin 1, 2 and 3 are GND, DQ and VCC respectively. Pin 14 of micro-controller is directly connected with pin 2 DQ of temperature sensor. In temperature sensor pin 3 VCC is connected to the pin 2 DQ via 4.7k resistor and pin 1 is ground. Pin 15 and 16 of micro-controller is connected to the buzzer and LED respectively. When temperature is greater than 69, buzzer and LED at flip-flop stage i.e. LED blinking and buzzer on-off (Figure 3). When temperature is greater than 79 buzzer and LED continuously on stage (Figure 4).Here any temperature can be set. Outside that condition the system is continuously show operating temperature of engine (Figure 5). Figure 3. Circuit diagram when LED and Buzzer off Figure 4. Circuit diagram when LED and Buzzer on flip-flop state Figure 5. Circuit diagram when LED and Buzzer continuously on Figure 7. Temperature Sensor Set in the Air-Coolec Diesel Engine Figure 8. LED Blinking and buzzer on-off Figure 9. Temperature Sensor Set in the Air-Cooled Petrol Engine Figure 10. Temperature Sensor Set in the Air-Cooled Petrol Engine Figure 11. LED and buzzer continuously on and loudly
