EE2016-Project Washing Machine Solved

To implement a fully functioning controller for a washing machine using AVR ATMEL ATmega8 Microcontroller. With the given inputs and outputs, write a program (assembly or C) and implement hardware emulation in the lab.

2          Engineering Problem
2.1            Basic operation sequence of a washing machine :-
There are 4 relays to be controlled in a regular sequence. The basic operation sequence is as follows

1.   Water filling (at actual time)

2.   Agitronic soak (15mins)

3.   First wash (15mins)

4.   First drain (4mins)

5.   Second wash or first rinse (10mins)

6.   Second drain (4mins)

7.   Spin (5mins)

8.   Buzzer chim (15sec)

2.2        Design Specifications
This includes both hardware and software specifications.

1.   The system should have three load conditions: Soft, Medium and Heavy. The user should be able to choose one.

2.   The system should have three tasks to choose from : Washing only, Drying only and Washing + Drying. These options should be made available for user input.

3.   The system should have two external interrupts. One interrupt acting as a "pause" button and theother as a "Lid open" interrupt.

4.   When the Pause interrupt is triggered, the user should be able to reset the load, washing cycle inputs.After the new inputs are given, the system should abandon the previous washing cycle and start off the new washing cycle.

5.   When the lid is open, the system should stop its functioning. Only after ensuring that lid is closed, theoperation may continue from where it left off.

3         Problem Definition
Inputs
Load Condition of the

Washing Machine

(Through Switches)
Soft
A.0
 
Medium
A.1
 
Heavy
A.2
 
Task to perform

(Through Switches)
Washing & Drying
A.4
 
Washing Only
A.5
 
Drying Only
A.6
 
 
Outputs (Displayed using LED’s)
 
 
Soft
Green LED will glow throughout the operation
B.0
 
Medium
Blue LED will glow throughout the operation
B.1
 
Heavy
White LED will glow throughout the operation
B.2
 
Washing (Soft load)
Two LED’s will glow for 2 seconds each for 3 times with a gap of 2 seconds
B.4,B.5
 
Washing (Medium load)
Two LED’s will glow for 2 seconds each for 5 times with a gap of 2 seconds
B.4,B.5
 
Washing (Heavy load)
Two LED’s will glow for 2 seconds each for 7 times with a gap of 2 seconds
B.4,B.5
 
Drying (Soft load)
Two Red LED’s will glow for 4 seconds
B.6
 
Drying (Medium load)
Two Red LED’s will glow for 8 seconds
B.7
 
Drying (Heavy load)
Two Red LED’s will glow for 12 seconds
B.8
 
After all the desired operations have been completed, sound a buzzer for 2 seconds indicating that the washing/drying cycle has been completed.

Program Flow

1.   The inputs are the load condition of the washing machine (soft, medium, heavy) and the task to perform(washing & drying, washing only, drying only), which is given by the user. The user enters the inputs through the switches which comes to the assigned ports (Please note port numbers can be changed after checking the datasheet).

2.   As mentioned in the above table, for the required inputs perform the required tasks and display theoutputs using LED’s.

3.   There is an extra input through a push switch corresponding to the Start button in the washing machine. This switch doubles up as a pause button which goes to the interrupt pin of the microcontroller.

4.   If the user presses the pause button, an interrupt will come and he/she can change any of the above inputs, i.e. he/she can change the load condition or the task to perform.

5.   Then according to the above changed rule, the washing machine has to perform the activity and displaythe output.