1. ENGR 1181 First-Year Engineering Program College of Engineering Engineering Education Innovation Center First-Year Engineering Program Solar Energy Meter Lab

2. ENGR 1181 First-Year Engineering Program Solar Energy Meter On a bright, sunny day, solar energy strikes the earth at the rate of approximately 1000 Watts/m 2 – this is called the solar energy intensity. In lab today, you will build a solar energy meter to measure the energy intensity from the sun at the earth’s surface.

3. ENGR 1181 First-Year Engineering Program Solar Energy Meter Parts Here 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.

4. 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

5. ENGR 1181 First-Year Engineering Program Solar Energy Meter “Schematic” A “schematic” is a drawing of an electronic circuit made by an electrical engineer.

6. ENGR 1181 First-Year Engineering Program Components The 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

7. ENGR 1181 First-Year Engineering Program Task 1 – Check the Breadboard Setup Measure the Power Supply Voltage, V = ______ Volts +5V Gnd

8. ENGR 1181 First-Year Engineering Program Task 2 – Calibrate the Binary Voltmeter

9. ENGR 1181 First-Year Engineering Program Task 2 – Calibration Circuit Breadboard

10. ENGR 1181 First-Year Engineering Program 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. Pins 1 2 3

11. ENGR 1181 First-Year Engineering Program 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 MSB LSB

12. ENGR 1181 First-Year Engineering Program The Decimal Equivalent of the Binary Number

13. ENGR 1181 First-Year Engineering Program 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

14. ENGR 1181 First-Year Engineering Program 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:

15. ENGR 1181 First-Year Engineering Program 8-bit Binary Numbers 00000101 = 5 LSB MSB …. + 0*2 3 + 1*2 2 + 0*2 1 + 1*2 0 = 5 For example, convert binary 0 0 0 0 0 1 0 1 into a decimal:

16. ENGR 1181 First-Year Engineering Program More Examples Binary Number Decimal Equivalent 113 1004 110113 11110161

17. ENGR 1181 First-Year Engineering Program 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

18. ENGR 1181 First-Year Engineering Program Task 2 – Calibrate the Binary Voltmeter Circuit Table A Set VoltageRecord Binary NumbersCalculate Decimal Values 00 0 0 0 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 Full CW

19. ENGR 1181 First-Year Engineering Program Task 3 – Solar Energy Meter Schematic

20. ENGR 1181 First-Year Engineering Program Task 3 – Solar Energy Meter Breadboard

21. ENGR 1181 First-Year Engineering Program 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 (I solar, Watts / m 2 ) The calibration equation for the Solar Light Meter is: I solar = 5.0 N decimal (Watts / m 2 ) I solar Amplifier Photodiode V Output

22. ENGR 1181 First-Year Engineering Program 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

23. ENGR 1181 First-Year Engineering Program 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.

24. ENGR 1181 First-Year Engineering Program Task 5 – Measure the Intensity of the Light Source at various distances Table B Distance ( Inches ) Binary NumberDecimal Value Intensity ( Watts / m 2 ) 23.0 19.0 15.0 11.0 7.0