• ENGR 1181 First-Year Engineering Program
College of EngineeringEngineering Education Innovation Center
First-Year Engineering Program
Solar Energy Meter Lab
• ENGR 1181 First-Year Engineering Program
Solar Energy MeterOn a bright, sunny day, solar energy strikes the earth at therate of approximately 1000 Watts/m2 – this is called the solar energy intensity.
In lab today, you will build a solar energy meter to measurethe energy intensity from the sun at the earth’s surface.
• ENGR 1181 First-Year Engineering Program
Solar Energy Meter PartsHere are the parts you will use:• +5 Volt modular power supply • DMM*
• Breadboard
* For a detailed explanation of the DMM, see the video from the Circuits Lab.
• ENGR 1181 First-Year Engineering Program
Solar Energy Meter “Circuit”
This is the circuit you will build:• Breadboard• Switch Box• Light Sensor• TrimPot• Binary Voltmeter• LED Display (8-bits)• Wires for connecting components
• ENGR 1181 First-Year Engineering Program
Solar Energy Meter “Schematic”
A “schematic” is a drawing of an electronic circuit made by an electrical engineer.
+5 V +5 V+5 V
P C B 1
Light S ensor
5
2 1
63 4
V O
ut
+5V
+5V
V O
ut
Gnd
Gnd
P C B 2
Bina ry Voltm e te r
6
2 1
75 14
4 3
8 9 10 11 12 13
D7
(MSB
)
+5V
+5V
D6
V In
put
Gnd
+5V
+5V
D5
D4
D3
D2
D1
D0
(LSB
)
D 7 D 6
D 5
D 4
D 3
D 2
D 1
D 0
BINA RY DISPL A Y
SHORTW IRE
S o la r E n e r g y M e te r C ir c u it
L EDs
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ComponentsThe parts (Components) you will use to build the
Solar Energy Meter are:• Light Sensor Board
• Senses the sun’s energy• Uses a Photodiode and an Op-Amp• Has an analog output voltage signal of 0 – 5 Volts
• Binary Voltmeter Board • Changes the input voltage signal to binary “Bits”
• LEDs• Display an 8-Bit binary number
• Wires• Connect the parts together electrically
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Task 1 – Check the Breadboard Setup
Measure the Power Supply Voltage, V = ______ Volts
+5V
Gnd
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Task 2 – Calibrate the Binary Voltmeter
+5 V
+5 V +5 V
1 0 K
P O T
13
2
P C B 2
Bina ry Voltm e te r
6
2 1
75 14
4 3
8 9 10 11 12 13
D7
(MSB
)
+5V
+5V
D6
V In
put
Gnd
+5V
+5V
D5
D4
D3
D2
D1
D0
(LSB
)
D 7 D 6
D 5
D 4
D 3
D 2
D 1
D 0
SHORTW IRE
B in a r y V o ltm e te r C a lib r a tio n C ir c u it
L EDs
0 to +5 V OL T S
BINA RY DISPL A Y
DMM
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Task 2 – Calibration Circuit Breadboard
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TrimPot• Total resistance (Pin 1 to Pin 3) = 10 kOhms• Resistance at Pin 2 varies by turning the small
adjustment screw (0 to +5V on Pin 2)• Use it to calibrate the Binary Voltmeter circuit• It is a variable resistor.
+5 V
1 0 K
P O T
13
2
Pins 1 2 3
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8-Bit Binary Display• The LEDs at the output of the
Binary Voltmeter are labeled from D7 to D0
• The LEDs have two digital states, on and off, representing the binary numbers “1” and “0”
• D7 is the Most Significant Bit (MSB). D0 is the Least Significant Bit (LSB)
• The 8-bit binary number can be converted to a decimal number using a formula
D 7 D 6
D 5
D 4
D 3
D 2
D 1
D 0
8-BIT BINA RY DISPL A Y
L EDs
MSB LSB
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The Decimal Equivalent of the Binary Number
•
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Why use Binary Numbers?
• Binary numbers are used in almost all computers due to its use of digital electronic circuitry and logic gates.
• Numbers are written in a combination of bits.
• Counting in binary is straightforward.
P. 13
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How does counting in Binary work?
• It works the same way that you have learned to count with Arabic numerals– Instead of 0-9, you now use only 0 & 1
• The pattern goes according to the following form: 8-Bit Binary
Number Decimal Equivalent
0000 0000 0 0000 0001 1 0000 0010 2 0000 0011 3 0000 0100 4 0000 0101 5 . . . . . . 1111 1110 254 1111 1111 255
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8-bit Binary Numbers
00000101 = 5
LSBMSB
…. + 0*23 + 1*22 + 0*21 + 1*20
= 5
For example, convert binary 0 0 0 0 0 1 0 1 into a decimal:
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More Examples
Binary Number
Decimal Equivalent
11 3
100 4
1101 13
111101 61
•
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Task 2 – Finish building the Calibration Circuit
+5V
Gnd
Short wire
• Connect the Binary Voltmeter board to Gnd (orange wire)
• Place the TrimPot as shown and:• Connect Pin 1 to
Ground• Connect Pin 3 to
+5 Volts• Connect Pin 2 to
V Input on the Binary Voltmeter
• Connect the LEDs• Connect the Red
DMM wire to V Input
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Task 2 – Calibrate the Binary Voltmeter CircuitTable A
Set Voltage Record Binary Numbers Calculate Decimal Values0 0 0 0 0 0 0 0 0 0
0.51.01.52.02.53.03.54.04.55.0
Full CW
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Task 3 – Solar Energy Meter Schematic
+5 V +5 V+5 V
P C B 1
Light Se nsor
5
2 1
63 4
V O
ut
+5V
+5V
V O
ut
Gnd
Gnd
P C B 2
Binary Voltm e te r
6
2 1
75 14
4 3
8 9 10 11 12 13
D7
(MSB
)
+5V
+5V
D6
V In
put
Gnd
+5V
+5V
D5
D4
D3
D2
D1
D0
(LSB
)
D 7 D 6
D 5
D 4
D 3
D 2
D 1
D 0
BINA RY DISPL A Y
SHORTW IRE
S o la r E n e r g y M e te r C ir c u it
L EDs
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Task 3 – Solar Energy Meter Breadboard
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Task 3 – How the Light Sensor Works
• The Photodiode converts light photons to a current
• The Amplifier converts the current to a voltage
• The voltage output of the Light Sensor Board is proportional to the intensity of sunlight (Isolar, Watts / m2)
The calibration equation for the Solar Light Meter is:
Isolar = 5.0 Ndecimal (Watts / m2)
Isolar
AmplifierPhotodiode
V Output
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Task 3 – Finish building the Solar Energy Meter
• Remove the TrimPot and its wires
• Plug in the Light Sensor Board (as shown)
• Add an orange ground wire
• Add a red wire from Vout to V Input
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Task 4 – Use the Solar Energy Meter to measure the intensity of a light source
• Place the spotlight in the ring stand so that the front of the bulb is 13 inches away from the top of the Light Sensor.
• Make sure that the Photodiode is directly in the center of the beam.
• Measure the Intensity of the light source at distances of 23, 19, 15, 11 and 7 inches.
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Task 5 – Measure the Intensity of the Light Source at various distances
Table B
Distance( Inches ) Binary Number Decimal Value Intensity
( Watts / m2)23.019.015.011.0
7.0