Senior Design Project
Intelligent Fish Tank
Xiao Feng Huang
TA: Jay Reppert
Fish and water are the symbols of wealth, which is one of the significant reasons that people
prefer to have a fish tank in their house. Nonetheless, people have to perform tasks, such as
changing the water, cleaning the tank, feeding the fish, and so on at certain time to provide the
suitable environment for the fish. Such tasks are sort of tedious, especially for those who do not
have too much spare time. Our project intends to eliminate these tedious tasks. We want to
build a fish tank which can operate these jobs automatically. Besides, each of the functionalities
of the fish tank can also be set to be operated manually and separately according to people’s will.
The purpose of this project is to release people from the time-consuming tasks of raising fish in
the fish tank. Our goal is to have a remote control that can select the operation mode of the fish
tank between automatic and manual. For the automatic mode, the control circuit of the fish tank
will control the heating and cooling system to keep the temperature of the water in the range
from 22oC to 27oC, control the water change system to change and filter the water making sure
the quality of the water suitable for fish living, and control the feeding system to feed the fish at
pre-set time. For the manual mode, people can change the water in the fish tank or feed the fish
by clicking the buttons of the remote control for specific operations.
To save people’s time on taking care of fish.
To provide the suitable and stable environment for fish.
To increase the interest of people in stocking fish.
The control system can be used for the large fish tank in some companies so that the
employers do not need to clean the fish tank by themselves or hire a cleaner to do so.
Use a remote control to switch the operation modes between automatic and manual.
Automatically heat or cool the water to keep the temperature of the water in a range from
22oC to 27oC via the measurement from the temperature sensor.
Automatically change and filter the water by sensing the quality of the water.
Automatically feed the fish at the pre-set time.
Manually change and filter the water via a remote control.
Manually feed the fish via a remote control.
II. Design (Block Diagram)
Buttons Signals Microcontroller Signals Transmitter Signals out
Fish Tank System
Signals from the temperature sensor
Signals from the conductivity sensor
n al s
Water Pump Water
Signals from the remote system
Fish Tank Interface
Signals out Signals out
Receiver Signals from the remote system
Signals from the conductivity sensor Microcontroller Signals from the temperature senser
Water From Fish Tank
Heater Water Pipe Cooler
Electric Valve Electric Valve
Water to the
Signals from the control circuit
Buttons: after users press the buttons to choose which operations they need, the buttons
will send the appropriate signals to the microcontroller.
Microcontroller: receive the signals from the buttons as inputs, decode the signals, and
output the appropriate signals to the transmitter.
Transmitter: receive the signals from the microcontroller as input and send them to the
Fish Tank System
Receiver: receive the signals from the transmitter in the remote system and output
the signals to the microcontroller.
Microcontroller: receive the signals from the receiver, temperature sensor and
conductivity sensor as inputs, compute the signals sequences through the build-in
program, and output the signal sequences to control the working status of the
water pump, feeder and water dispenser.
Water Pump: controlled by the control circuit to pump the water flowing out of the
water dispenser into the fish tank
Temperature Sensor: measure the temperature of the water and output the
signals to the microcontroller.
Conductivity Sensor: measure the conductivity of the water and output the
signals to the microcontroller.
Feeder: controlled by the control circuit to feed the fish automatically
Water Dispenser System:
Electrical Valves: controlled by the control circuit to open or close appropriately
to force the water into the heater, cooler, or the normal water pipe to flow out into
the water pump.
Water Filter: filter the water from the fish tank when the water pass through
Heater: heat the filtered water when the water flows in
Cooler: cool the filtered water when the water flows in
Water Pipe: let the room-temperature filtered water flow through to the water
Since the water dispenser is used in the system, the fish tank requires an 110V AC power supply
for the water dispenser. An 110V AC to 5V DC converter is also needed for the power supply of
the control circuit. In addition, the remote control requires 6V battery power supply. The
transmission range of the transmitter is at most 50 feet.
Remote circuit function
One of the initial tests will be to test the remote circuit. We are going to set four buttons on the
remote control, one for power, one for mode change, one for the water change function, and one
for the food feeding function. We will use the oscilloscope to measure differences of analog
outputs of each button to make sure the microcontroller receive the correct output from the
Antenna transmission and receive
Next test will be to determine antenna transmission system. We will use the function generator to
generate a certain signal at the transmitter side and let it propagate through an antenna. On the
receiver side, the receiver should be able to pick up that signal transmitted beforehand and
recover it. The recovered signal should be almost identical to the transmitted one.
Feed food system
Feed food system the highlight feature in this fish tank. It consists of a container and a “door”
which is electrically controlled by the microcontroller. On automatic mode, the door should be
“open” at the pre-set time so that the food can go into the fish tank. On user mode, when the feed
food button on the remote is clicked, the door should “open” correspondingly.
Water pump control system
The water pump system is always connected to the power supply with a switch. However, the
signal from the microcontroller will determine when the switch is closed and when the pump
starts functioning. In the automatic mode, when the water quality control or the temperature
control starts functioning, the pump should be automatically activated. In the user mode, when
the water change button is clicked, the water pump should be working accordingly.
Temperature control system
Hot and cold water will be used to test the temperature control system. If the system senses that
the water is too hot, the electrical valve will open and the water will go through the cooling
system. On the other hand, if the cold water goes into the tank, they will be sensed and allowed
to go through the heating system.
Water quality control
We will use the contaminated water to test the water quality control system. Once the dirty water
is detected, the electrical valve will open will the water will just simply pass the filter without
any heating or cooling procedure.
In order to test microcontroller, we will send the transmitted signal into the PIC chip and obtain
the outputs from various components around the fish tank, such as pump, electric valves and
feeding system door. We will make sure the output is exactly what we expected to get the entire
Temperature sensors and conductivity sensor
Whether the temperature control system and the water quality control system work depends on
not only the microcontroller signal, but also on the sensor signals. If the water is merely “kind
of” dirty but not dirty enough for the sensor to detect it, the water quality system may not
function as expected. Likewise, as temperature is not uniform inside water, so the different
locations of the temperature sensor will have different effects on the performance. Therefore, if
the water is just a little bit dirty, the water conductivity will not change significantly. In this case
the water quality control may not work, but it is tolerable. Similarly, if the fish tank temperature
is no more than +2ºC or -2ºC beyond the acceptable temperature range, it will also be tolerated.
IV. Cost and Schedule
Name Hourly Wage Total
Haipeng Lin 2.5x180 hours x $50/hour $22,500
Xiao Feng Huang 2.5x180 hours x $50/hour $22,500
Part Price per Unit Quantity Total Price
Fish Tank $16 1 $16
Temperature sensor $20 1 $20
Photo sensor $5 4 $20
PIC16F877 $6 2 $12
UHF Transmitter $10 1 $10
UHF Receiver $10 1 $10
Battery pack $5 1 $5
OpAmp $1 1 $9
Electric valve $20 4 $80
Water dispenser $100 1 $100
110 V ac to 5 V dc converter $11 1 $11
Resistors, Capacitors $0.03 10 $0.3
Real time clock(RTC) $2 1 $2
Total Cost = $45000+$268.3=$45284.3
Sep. 6 – 12 Ideas for Design Ideas for Design
Sep. 13 – 19 Gather Parts/Write Proposal Research sensors/Write Proposal
Sep. 20 – 26 Prepare for Design Review Prepare for Design Review
Sep. 27 – Oct. 3 Build remote circuit Program microcontroller
Oct. 4 – 10 Build transmission circuit Set up water change system
Oct. 11 – 17 Set up temperature control system Set up water quality system
Oct. 18 – 24 Test the remote circuit Set up the feed food system
Oct. 25 – 31 Test the transmission circuit Test the microcontroller
Nov. 1 – 7 Test the water change system Test the water quality system
Nov. 8 – 21 Test the temperature control system Test the feed food system
Nov. 22– 28 Project testing Project testing
Nov. 29 –Dec. 6 Final Paper, Presentation, and Demos Final Presentation, Demos and Paper
For the common work in both Haipeng and Xiao’s work column.
Haipeng will be in charge of Ideas for Design, Prepare for Design Review, and Final Paper.
Xiao will be in charge of Write Proposal, Final Presentation, and Demos.