Aquatic Life System

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Aquatic Life System
BECAUSE FISH ROCK
Final Design Review - March 24, 2004
Zach Casper, Richard Dunkley, Blake Hunsaker, and
Paul Smart
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ALS Must Maintain/Monitor

• Temperature
• pH

• Water Level
• Feeding and Food Level

Reservoir
Embedded System
PC
Water Inlet Valve
Feeder
Temp Sensor
pH Sensor
Heater
Water Outlet Valve
Drain
Water Level Sensors
LCD
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Aquatic Life System (ALS)

• Embedded System
• Microcontroller
• (MC68HC11E0)
• External 32K Memory for
• program storage
• USB Module for serial interface

MC
Feeder Motor Control
Feed Control
Feeder Rotation Counter
Food Level Sensor
External Memory BQ4011 MA-100
Inlet (Fill) Valve Control
Water Level Control
Outlet (Drain) Valve Control
Water Level Sensors
pH Sensor
pH Control
A/D Converter
Temp Sensor
Temperature Control
Heater
LCD

• Aquarium / World
• 2 Analog Inputs
• 4 Digital Inputs
• 4 Actuators Outputs
• PC user interface and non-PC display

USB Module
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ALS Embedded System Schematic
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External (to board) Circuitry These circuits are
not on the printed Circuit board but are
necessary for operation
This is the reset circuit for the microcontroller
This circuit is a temporary solution to our
communications problem regarding the use of a
virtual com port with the loading programs. This
circuit replaces the USB interface with a simpler
serial port connection. It will only be used
until a suitable loader program can be found
will accommodate the USB module.
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• PCB Layout Using LAYOUT PLUS
• 2 Layers Silkscreen

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Printed Circuit Board Unpopulated
TOP VIEW
BOTTOM VIEW
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Motorola MC68HC11E0

• 5 Ports
• 8 Channel / 8 bit A/D Converter
• Integrated Serial Communications Interface
• 16 Bit Address Bus
• 8 Bit Data Bus
• 4.2V Min HIGH Out, -0.4V Max for LOW Out
• 3.5V Min HIGH Input, 5.3V Max HIGH Input
• 1.0V Max Low Input, -0.3V Min Low Input

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Motorola 68HC11E0 Block Diagram
512 RAM
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Microcontroller Assignments
PORT
Internal Features
Assignments
8 Bit Pulse Accumulator
Feeder Rotation Counter
Outlet Valve
Inlet Valve
A
Feeder Motor
Water Heater
Food Level Sensor
Water Level Sensor
Water Level Sensor
Memory Chip / LCD Select (Mem 8000-FFFF)
B
Memory Chip / LCD Select (LCD 4000-7FFF)
ADDR High
Expanded Mode Address / Data Bus
60
C
DATA / ADDR Low (Memory and LCD)
80
D
Serial Communication Interface (SCI)
RxD
TxD
USB Module
RxD
TxD
E
8 Bit A/D
Temperature Sensor
pH Sensor
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USB MODULE
Single module High-Speed USB UART solution
Integrated Type-B USB Connector On-board 6MHz
Crystal External EEPROM on board for USB
enumeration data
USBMOD3
Motorola 68HC11E0
FTDI FT232BM USB UART IC
Tx
Rx
SCI Interface
Tx
Rx
USB BUS TO PC
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LCD
MTC-C162DPLY-2N

• Displays
• pH
• Temperature

• Command Memory Locations
• 40xx Write Instruction
• 41xx Read Instruction
• 42xx Write Data
• 43xx Read Data

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Automatic Feeder Design

• Requirements
• Must be controlled by microcontroller
• Must be able to dispense food for different
  amounts of fish
• Must be able to dispense food at different
  intervals if necessary
• Needs to sense when food level in feeder is too
  low

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Microcontroller (MC)
0V OFF 3V ON
0.4V OFF 4.2V ON
Conditioning Circuit (Relay)

• Nutra-matic Feeder
• Includes
• Plastic Case
• Motor
• Gearing

1V Low 3.5V High
Switch
To Pulse Accumulator
1V Level OK 3.5V Food Low
Food Level Sensor
68HC11
Switch Circuit
Food goes in here

• Feeder Control
• 3V for continuous ON
• Each full turn will dispense food and
• activate the switch
• MC activates motor to control the
• number of feeder rotations

GEARING
MOTOR
Switch
Rear View of Feeder
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Feeder Control
16
Food Level Detector
Photocell
3.5V High
Feeder
Feeder
Food
Food
Food Okay Photocell blocked from light (High
Resistance Open Circuit)
Food Low Photocell exposed (Low Resistance
Closed Circuit)
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Food

• System will be configured to use flake food
• Each rotation will drop approximately ¼ teaspoon
  of food (1 pinch) this is equivalent to what 1
  average size fish can eat in 2 minutes
• These rotations ( and intervals) will occur as
  specified in GUI by user

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Feeders Action
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Temperature Control
Temperature Sensor
Signal Conditioning
Microcontroller 8 Bit A/D
Heater
Relay
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Temperature Control

• Requirements
• Must maintain temperature within
• 3 degrees Fahrenheit of desired setting (76-78
  degrees for most fish)
• Must avoid rapid fluctuation in temperature (10
  degrees in 12 hours)

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Temperature Sensor

• National Semiconductor LM34CAZ
• 1.11 degrees Fahrenheit accuracy
• 5-30 VDC supply voltage

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Temperature ControlSignal Conditioning
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Temperature vs. Voltage
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Example A/D Results for Temperature Sensor
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Heater

• Heating coil in plastic casing
• 50 Watts

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Relay

• 5 VDC coil
• 1 Amp contact rating

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Heater Control
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Water Input/Output Control
Water Level Sensors
Inlet Valve
Microcontroller
Outlet Valve
pH Sensor
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Water Input/Output Control

• Requirements
• Draining and filling of tank are activated based
  on readings from pH sensor
• Water level will never become too high or too low
  1 inch top level, 5 inches bottom level

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Water Level Control
Water Source
Water Level Sensors
Desired Water Level
Drain
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Water Level Sensors

• Simple open/close switch
• Small size

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Water Level Sensors
To Microcontroller Upper Level Sensor PA0 Lower
Level Sensor PA1
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Valves

• 120 VAC solenoid
• Normally closed
• ¼ inch and ½ inch hose connections
• Flow rate .1gal/min.

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Valve Control
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pH Control
pH Sensor
Signal Conditioning
Microcontroller 8 Bit A/D
Valves
Relay
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pH Sensor

• Requirements
• Monitor concentration of hydrogen ions in an
  aqueous solution
• 0 to 14 pH range
• Fast response time
• Accurate readings

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Sensor Input Specifications

• Pin 1 Sensor Output
• Pin 2 Not used
• Pin 3 ID Output (not used with most sensors)
• Pin 4 Power (5VDC)
• Pin 5 GND

Circular DIN Plug - 5 pin
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The ideal pH electrode

• Zero volts output at neutral pH (7.0)
• Positive voltage in acids, pHlt7
• Negative voltages in bases, pHgt7
• Generates -59.16 millivolts per pH unit at room
  temperature ("Nernst potential").

Nernst potential calculation of the exact
electrical potential at equilibrium that is


generated for a known
concentration difference in a specific ion,
separated by a membrane permeable to that
ion.
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pH electrode

• 1.75 volts output at neutral pH (7.0)
• Increase by .25 volts/pH level in acids, pHlt7
• Decrease by .25 volts/pH in bases, pHgt7
• Response time in 1 second

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pH ControlSignal Conditioning
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pH Level vs. Voltage
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Example A/D Results for pH Sensor
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Water Quality and pH

• If the level of H ions increases, the substance
  is considered an acid and the pH number is below
  7.
• If the level of OH- ions increases, the substance
  is considered to be alkaline or base and the pH
  number is above 7.

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Power Considerations
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Basic Cost Breakdown
Printed Circuit Board Advanced Circuits
45.00 LCD hobbyengineering.com 13.50 USB
Module hobbyengineering.com 26.00 MC68HC11E0
Digikey 10.00 32K RAM Chip Digikey
10.50 Resistors, Capacitors, Logic Gates, Misc.
ECE Store 20.00 Relays Radioshack 3.99 x
3 Photocells Radioshack 3.50 Input/Ouput Water
Valves Online 22.00 x 2 Water Level Sensors
Digikey 10.00 x 2 Temperature Sensor National
Semi 0.00 Feeder PetSmart 15.00 Time spent
working on the ALS Priceless