Microprocessor for microwave oven

Presentation on micro processor application on micro oven

1. Made by: Akash lal Microprocessor for Microwave Oven

2. The Microprocessor Many gadgets, devices, appliances and machines have microprocessors controlling their operation.

3. For a microprocessor to control device, it has to: For a microprocessor to control device, it has to: Make decisions based on the detected changes. Activate appropriate output devices according to decisions made. Input Devices Input Process Microprocessor Controller System Process Output Devices Output

4. Component Here are some of the devices are used in a microwave oven: A microwave generator produces the microwaves that cook the food. A lamp illuminates during the cooking process. A motor drives a turntable so that the food rotates and cooks evenly. A display indicates the cooking time and the selected cooking mode. A sounder beeps when the cooking period is complete. The keypad enables the cooking time to be set, cooking mode to be entered and START/STOP cooking selected. A door switch detects when the door is open. A fan removes steam that is generated by cooking.

5. To control the operation of the microwave oven, there is a printed circuit board (PCB) containing the microprocessor system.

6. Power Supply in Oven To power the microprocessor and the various devices, the microwave oven is connected to the power source. The power source is a high voltage, alternating current (AC) supply. The circuitry of the microprocessor and some of the devices require a lower, direct current (DC) voltage. A power supply unit converts the AC supply to the required DC voltage level.

7. Input Devices The INPUT devices to the microprocessor system are: The keypad The door switch

8. Door Switch The door switch requires one input line to the microprocessor system. The input line is a wire that carries an electrical signal from the door switch to the microprocessor system. The switch could be in one of two positions. With the door open the switch would be open, and with the door closed the switch would be closed. The microprocessor can determine the position of the switch by the electrical signal on the input line.

9. Keypad The keypad has many buttons and requires several lines connecting it to the microprocessor system. For each button pressed on the keypad, a unique digital code is sent to the microprocessor. In this way the microprocessor is able to detect which button has been pressed.

10. Output Devices The output devices from the microprocessor system are: Microwave generator Turntable motor Display Lamp Sounder Fan

11. Here are the input and output connections to and from the microprocessor.

12. If the microprocessor and devices are taken out of the cabinet, we can view the connections more easily. Timer

13. System Operation The cooking mode is selected on the keypad and the cooking period set. The microprocessor reads the settings input on the keypad into its memory. Signals are sent to the display to indicate the cooking mode and cooking period set.

14. When the START button is pressed and the door is shut, the microprocessor carries out the following: Starts the electronic timer with the cooking period Switches the fan on Switches the lamp on Starts the turntable motor running Switches the microwave generator on The microprocessor is able to carry out these tasks very quickly so they appear to happen at the same time.

15. If the door is opened, the microprocessor will detect it and stop the cooking process by switching off the fan, microwave generator and turntable motor. It may also put a message on the display, DOOR OPEN.

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