Electric Liquid Sensing
System
for Railroad Lubricant
Tank
ECE 480 – Team 8
George P. Ballios – Lab Coordinator / Presentation Prep
Michael W. Dow – Webmaster
Nicholas T. Vogtmann – Document Prep
Craig M. Zofchak – Manager
Overview
Sponsor
 Problem
 Design
Specifications
 Results
 Future
Improvements

Sponsor

Sponsored by Norfolk
Southern Corporation
• Class one railway system
operator
• 21,000 route miles in 22 eastern states
• Serves all major eastern ports
• Comprehensive logistic services
• Most extensive intermodal network in
the east
Mission
Norfolk Southern desires a way of
shutting off the pump for there
lubrication system when the liquid
level reaches it low point
 Currently there is no system in place
to measure the lubricant level

• Norfolk Southern visit’s the tank’s site
every one to three months for refilling
Design Requirements

Keep structural integrity intact
• Any modification is impractical while it is
operational
• Debris in the tank can damage the pumps

Low Power Consumption
• Runs off a car sized battery
• Charged by a solar panel


The lubricant has a tendency to bond
to other objects
Lubricant solidifies when exposed to
air for an extended period
End-Product Description:

The level detection system consists of three
unique sensors
• Ensures precision and robustness

A microcontroller calculates the three
sensor’s data
• Shuts off the pump
Audio Frequency Sensor
Solenoid that strikes the tank
 Microphone to pick-up the audio
vibrations
 Resonance frequency changes as
liquid level changes

• Frequency of air opposed to frequency
of water
MATLAB Audio Frequency Code
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clc;
close all;
clear all;
figure;
[x, Fs, N]=wavread('MidLevel1.wav');
fx = fft(x,Fs);
fx1 = fx(1:length(fx)/2);
hold on
title 'Mid Level'
plot(abs(fx1),'r')
axis([0 2500 0 1000])
mm(1) = find(fx1==max((fx1)));
ml(1) = max(abs(fx1));
mml = mm(1);
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[x, Fs, N]=wavread('MidLevel2.wav');
fx = fft(x,Fs);
fx2 = fx(1:length(fx)/2);
hold on
plot(abs(fx2),'g')
mm(2) = find(fx2==max((fx2)));
ml(2) = max(abs(fx2));
if (ml(2) >= max(ml))
mml = mm(2);
end
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[x, Fs, N]=wavread('MidLevel3.wav');
fx = fft(x,Fs);
fx3 = fx(1:length(fx)/2);
hold on
plot(abs(fx3),'y')
mm(3) = find(fx3==max((fx3)));
ml(3) = max(abs(fx3));
if (ml(3) >= max(ml))
mml = mm(3);
end
[x, Fs, N]=wavread('MidLevel4.wav');
fx = fft(x,Fs);
fx4 = fx(1:length(fx)/2);
hold on
plot(abs(fx4))
mm(4) = find(fx4==max((fx4)));
ml(4) = max(abs(fx4));
if (ml(4) >= max(ml))
mml = mm(4);
end
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if(abs(fx1(mml))>400 & abs(fx2(mml))>400 & abs(fx3(mml))>400
& abs(fx4(mml))>400);
MidLevel_Max_Peak = mml
else
MidLevel_mean_Max_Peak = mean(mm)
end
MATLAB Audio Frequency Code
cont.
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figure;
clear all;
[x, Fs, N]=wavread('MidLevel-15G1.wav');
fx = fft(x,Fs);
fx1 = fx(1:length(fx)/2);
hold on
title '15 Gallons down from Mid Level'
plot(abs(fx1),'r')
AXIS([0 2500 0 1000])
mm(1) = find(fx1==max((fx1)));
ml(1) = max(abs(fx1));
mml = mm(1);
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[x, Fs, N]=wavread('MidLevel-15G2.wav');
fx = fft(x,Fs);
fx2 = fx(1:length(fx)/2);
hold on
plot(abs(fx2),'g')
mm(2) = find(fx2==max((fx2)));
ml(2) = max(abs(fx2));
if (ml(2) >= max(ml))
mml = mm(2);
end
[x, Fs, N]=wavread('MidLevel-15G3.wav');
fx = fft(x,Fs);
fx3 = fx(1:length(fx)/2);
hold on
plot(abs(fx3),'y')
mm(3) = find(fx3==max((fx3)));
ml(3) = max(abs(fx3));
if (ml(3) >= max(ml))
mml = mm(3);
end
[x, Fs, N]=wavread('MidLevel-15G4.wav');
fx = fft(x,Fs);
fx4 = fx(1:length(fx)/2);
hold on
plot(abs(fx4))
mm(4) = find(fx4==max((fx4)));
ml(4) = max(abs(fx4));
if (ml(4) >= max(ml))
mml = mm(4);
end
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if(abs(fx1(mml))>400 & abs(fx2(mml))>400 & abs(fx3(mml))>400
& abs(fx4(mml))>400);
MidLevel_15GD_Max_Peak = mml
else
MidLevel_15GD_mean_Max_Peak = mean(mm)
end
MATLAB Audio Frequency Code
cont.
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figure;
clear all;
[x, Fs, N]=wavread('MidLevel-30G1.wav');
fx = fft(x,Fs);
fx1 = fx(1:length(fx)/2);
hold on
title '30 Gallons down from Mid Level'
plot(abs(fx1),'r')
AXIS([0 2500 0 1000])
mm(1) = find(fx1==max((fx1)));
ml(1) = max(abs(fx1));
mml = mm(1);
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[x, Fs, N]=wavread('MidLevel-30G2.wav');
fx = fft(x,Fs);
fx2 = fx(1:length(fx)/2);
hold on
plot(abs(fx2),'g')
mm(2) = find(fx2==max((fx2)));
ml(2) = max(abs(fx2));
if (ml(2) >= max(ml))
mml = mm(2);
end
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[x, Fs, N]=wavread('MidLevel-30G3.wav');
fx = fft(x,Fs);
fx3 = fx(1:length(fx)/2);
hold on
plot(abs(fx3),'y')
mm(3) = find(fx3==max((fx3)));
ml(3) = max(abs(fx3));
if (ml(3) >= max(ml))
mml = mm(3);
end
[x, Fs, N]=wavread('MidLevel-30G4.wav');
fx = fft(x,Fs);
fx4 = fx(1:length(fx)/2);
hold on
plot(abs(fx4))
mm(4) = find(fx4==max((fx4)));
ml(4) = max(abs(fx4));
if (ml(4) >= max(ml))
mml = mm(4);
end
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if(abs(fx1(mml))>400 & abs(fx2(mml))>400 & abs(fx3(mml))>400
& abs(fx4(mml))>400);
MidLevel_30GD_Max_Peak = mml
else
MidLevel_30GD_Max_Peak = mean(mm)
end
MATLAB Audio Frequency Code
cont.
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figure;
clear all;
[x, Fs, N]=wavread('MidLevel-45G1.wav');
fx = fft(x,Fs);
fx1 = fx(1:length(fx)/2);
hold on
title '45 Gallons down from Mid Level'
plot(abs(fx1),'r')
AXIS([0 2500 0 1000])
mm(1) = find(fx1==max((fx1)));
ml(1) = max(abs(fx1));
mml = mm(1);
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[x, Fs, N]=wavread('MidLevel-45G2.wav');
fx = fft(x,Fs);
fx2 = fx(1:length(fx)/2);
hold on
plot(abs(fx2),'g')
mm(2) = find(fx2==max((fx2)));
ml(2) = max(abs(fx2));
if (ml(2) >= max(ml))
mml = mm(2);
end
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[x, Fs, N]=wavread('MidLevel-45G3.wav');
fx = fft(x,Fs);
fx3 = fx(1:length(fx)/2);
hold on
plot(abs(fx3),'y')
mm(3) = find(fx3==max((fx3)));
ml(3) = max(abs(fx3));
if (ml(3) >= max(ml))
mml = mm(3);
end
[x, Fs, N]=wavread('MidLevel-45G4.wav');
fx = fft(x,Fs);
fx4 = fx(1:length(fx)/2);
hold on
plot(abs(fx4))
mm(4) = find(fx4==max((fx4)));
ml(4) = max(abs(fx4));
if (ml(4) >= max(ml))
mml = mm(4);
end
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if(abs(fx1(mml))>400 & abs(fx2(mml))>400 & abs(fx3(mml))>400
& abs(fx4(mml))>400);
MidLevel_45GD_Max_Peak = mml
else
MidLevel_45GD_Max_Peak = mean(mm)
end
MATLAB Audio Frequency Code
cont.
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figure;
clear all;
[x, Fs, N]=wavread('CriticalLevel1.wav');
fx = fft(x,Fs);
fx1 = fx(1:length(fx)/2);
hold on
title 'Critical Level'
plot(abs(fx1),'r')
AXIS([0 2500 0 1000])
mm(1) = find(fx1==max((fx1)));
ml(1) = max(abs(fx1));
mml = mm(1);
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[x, Fs, N]=wavread('CriticalLevel2.wav');
fx = fft(x,Fs);
fx2 = fx(1:length(fx)/2);
hold on
plot(abs(fx2),'g')
mm(2) = find(fx2==max((fx2)));
ml(2) = max(abs(fx2));
if (ml(2) >= max(ml))
mml = mm(2);
end
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[x, Fs, N]=wavread('CriticalLevel3.wav');
fx = fft(x,Fs);
fx3 = fx(1:length(fx)/2);
hold on
plot(abs(fx3),'y')
mm(3) = find(fx3==max((fx3)));
ml(3) = max(abs(fx3));
if (ml(3) >= max(ml))
mml = mm(3);
end
[x, Fs, N]=wavread('CriticalLevel4.wav');
fx = fft(x,Fs);
fx4 = fx(1:length(fx)/2);
hold on
plot(abs(fx4))
mm(4) = find(fx4==max((fx4)));
ml(4) = max(abs(fx4));
if (ml(4) >= max(ml))
mml = mm(4);
end
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if(abs(fx1(mml))>400 & abs(fx2(mml))>400 & abs(fx3(mml))>400
& abs(fx4(mml))>400);
Cricital_Level_Max_Peak = mml
else
Cricital_Level_Max_Peak = mean(mm)
end
Water is Above Critical Level
15 Gallons down from Mid Level
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Mid Level
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30 Gallons down from Mid Level
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Water is Below Critical Level
Critical Level
45 Gallons down from Mid Level
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Temperature-Based Sensor
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Series of temperature sensors
• Placed at equally spaced levels along
the tank wall

The difference in temperature
determines the level
Can You Guess the
Lubricant Level?
Float Sensor with Magnetic Reed
Switch

Floating Magnet in an enclosed track
• Enclosed track is 2” from the wall
Reed Switch is placed at shut off
level
 When the floating magnet is in the
range of the reed switch the pump
shuts off

Reed Switch Operation
Budget
Final Estimated Cost per Unit
Qty
Proposed Estimated Cost
Item
Cost
Sonar Gun
$250.00
PCB
$100.00
Windshield Wiper
Motor
$50.00
Precision
Microphone
$50.00
Mallet/Hammer
$15.00
Total
Part
Unit Price
Total
1
Digital Signal Controller
$4.26
$4.26
1
Printed Circuit Board
$50.00
$50.00
1
Suction Cup Microphone
$11.99
$11.99
1
Magnetic Reed Switch
$14.32
$14.32
1
Neodymium Iron-Boron
Magnet Pack
$29.99
$29.99
6
Precision Temperature
Sensor
$2.89
$17.34
1
Plastic Enclosures
$6.82
$6.82
1
Miscellaneous Parts /
Hardware
$20.00
$20.00
Grand Total
$154.72
$465.00
Building it better

The system could be fully external
• Higher cost
• Not as accurate

Items could have a more permanent attachment
• Liquid bonding agent, not duct tape

The audio sensor could have the ability to
determine the level
• Not just the point where the pump needs to be shut off


Use of Ultrasound
Long range communication
Issues Along the Way
Ultrasound
 RFID
 Audio
 Field Demo
 Physical Properties of the Tank

• Steel

Filling of Tank for Level Testing
Summary
When the lubricant reaches the
critical point the pump shuts off
 Three Sensors

• Audio Frequency
• Temperature
• Reed Switch
No Modification of Existing System
 Easily Implemented

Questions