A .
Introduction:
A dishwasher is an electromechanical device that combines both mechanical and electrical components.
It uses motors to pump water and rotate spray arms, while heating elements warm the water and aid in
drying dishes. The dishwasher is equipped with sensors that track water levels, temperature, and
detergent usage.
B .Parts of Dishwasher:
C .Architecture Diagram:
D .Architecture Overview:
1. User Interface (UI): MCU3 handles the user interface, including the LCD display, touch
buttons, LEDs, and buzzer. It allows users to select washing cycles and provides visual and
audible feedback.
2. Connectivity: Zigbee/Mbus Modules enable wireless connectivity for smart home integration
and remote control, facilitating data exchange with external devices.
3. System Management:MCU1 acts as the central control unit, managing power, sensor data, and
actuators (water valves, door locks, heating elements). It also monitors temperature and ensures
efficient operation.
4. Motor Control :MCU2 controls the motor and drying fan using a Triac and power module,
often utilizing PWM for precise speed control.
5. Sensors and Actuators :MCU1 also manages various actuators (water valves, door locks) and
sensors (temperature, water level), using Triacs for switching high-power devices.
6. Protection Components :ESD/TVS protection and discrete components safeguard the system
from surges and electrostatic discharge, while logic gates handle control signals.
E .Data Path in the Dishwasher System:
1. User Input
• Users interact with buttons or the display. MCU3 captures and manages these interactions.
2. Processing Input
• MCU3 sends the user input to MCU1 (main control). MCU1 decides what actions the
dishwasher should take.
3. Sensor Data Collection
• MCU1 collects data from key sensors:
o Water level sensors to check water quantity.
o Temperature sensors to monitor water heat.
o Turbidity sensors to assess water cleanliness.
4. Communication Between MCUs
• MCU1 sends instructions to MCU2 (controls motor and fan) and other components like heating
elements and water valves.
5. Output Control
• Actions are triggered:
o The motor operates for washing and drying.
o The display shows cycle status, and LEDs provide user feedback.
F .Processor Memory in the Dishwasher System :
I .RAM (Random Access Memory)
Purpose: Used as temporary storage while the dishwasher is running.
Functionality:
Stores real-time data and cycle status (e.g., pre-wash, rinse).
Holds sensor readings during operation.
Being volatile, RAM loses all data when the power is turned off.
II .EEPROM (Electrically Erasable Programmable Read-Only Memory)
Purpose: Used for long-term data storage.
Functionality:
Stores data that must be kept even when the dishwasher is off, such as:
Wash cycle programs (e.g., normal, heavy-duty).
User settings like preferred temperatures or cycle options.
Error logs for diagnosing issues.
EEPROM is non-volatile, so data remains available even after the dishwasher is turned off.
G. Types of Instructions Implemented:
s.no Type of Purpose/Use Example Instruction How the Dishwasher
Instruction Instruction Component
Works
1. Transfer data MOV R1, Transfers the Water
between [WATER_SENSOR] water sensor sensor, CPU
memory, data from registers,
registers, and memory into user inputs
Data
I/O devices. the CPU
Transfer
register (R1),
Instructions
enabling the
CPU to access
real-time water
levels.
2. Arithmetic Perform 1.CMP R1, R2 – Compares the Water heater
and Logic mathematical Compare current and current (temperature
Instructions operations and desired temp. temperature control),
logical 2.ADD R3, R1, R2 – (R1) with the water level
comparisons. Add water volumes desired value sensor
(R2) to decide
whether to heat
water. Adds the
current water
volume to the
required
volume.
3. Branching Direct program 1.JMP If the water Inlet valve
Instructions flow based on OPEN_VALVE – level is too control,
conditions. Jump to open inlet low, the CPU water
valve jumps to the temperature
2.BNE instruction to monitoring,
NEXT_STAGE – open the inlet user-selected
Branch to next stage valve and add cycle
water. If the
desired
temperature is
not reached,
branches to
heating.
4. I/O Exchange data 1 .IN R4, Reads the Motor, spray
Instructions between the MOTOR_STATUS – motor's status arms, inlet
CPU and Read motor status to check if it is valve, drain
external OUT running pump,
components. VALVE_CONTROL, properly. Sends temperature
R1 – Control valve control signals sensor,
to the valve to actuators
open/close
based on
system needs.
5. Control Manage the HLT – Halt if door Halts the Door sensor,
Instructions execution of opened program user control
instructions and NOP – Do nothing execution if the interface
handle (pause) door is opened.
synchronization. Pauses the
execution
while waiting
for a specific
condition (e.g.,
waiting for
water to reach
the right
temperature).
6. Bit Modify specific 1.SETB Sets a bit in the Heating
Manipulation bits in registers HEAT_ON_FLAG – register to turn element
Instructions for control or Turn on heating on the heating control, door
status tracking. 2.CLR element. Clears status, wash
DOOR_OPEN_FLAG the bit when cycle status
– Clear door open flag the door is flags
closed to
resume the
operation.
7. Shift and Shift or rotate SHL R1, 2 – Multiply Shifts bits in Sensor data
Rotate bits in registers sensor value the register to scaling
Instructions for scaling or ROR R2, 1 – Rotate multiply sensor (temperature,
adjusting register bits data by a water level),
control signals. power of 2, PWM
useful for control for
adjusting motor speed
values. Rotates
bits in a
register for
data
manipulation.
8. Stack Temporarily PUSH R1 – Push Door
Pushes current
Instructions store data using current cycle state opening
cycle data onto
Last In, First POP R2 – Resume events.
the stack when
Out (LIFO) from saved state after
an interrupt
structure. interrupt
