DIY Solar Tracker Experiment: Energy Yield Comparison

Sun position is determined using two angles: azimuth (measured clockwise from north) and altitude (measured from the horizon). At sunrise, azimuth is ~90° (east) and altitude is 0°; at noon, azimuth is ~180° (south) with maximum altitude; at sunset, azimuth is ~270° (west) and altitude returns to 0°. A Sun path diagram plots these angles on x-axis (azimuth) and y-axis (altitude), showing the Sun's daily arc. Northern hemisphere observers see the Sun in the southern sky, while southern hemisphere observers see it in the northern sky. The diagram's curve changes daily due to Earth's axial tilt of 23.4°, causing seasonal variations in Sun altitude and azimuth.

Azimuth is the angular direction of an object measured from north, clockwise. To measure azimuth, face north and measure the angle to your target. The sun's azimuth changes throughout the day and varies by season. When the sun crosses the local meridian (solar noon), its azimuth is 180 degrees (due south in the northern hemisphere). The rate of azimuth change varies: slower when the sun is far from the meridian, faster when near midday. This variation occurs because the sun's path across the sky is curved rather than perpendicular to the horizon.

Solar geometry determines sun position for any location, time, and date. Three factors affect sun position: latitude, time of day, and time of year. Earth has two movements: rotation (24 hours, creating day/night) and translation (365 days, creating seasons). The elliptical orbit causes varying Earth-sun distances (aphelion in winter, perihelion in summer), but axial tilt (23°27') has greater impact on seasonal patterns. Four key dates mark seasons: December 21 (summer solstice), March 21 (autumn equinox), June 21 (winter solstice), September 23 (spring equinox). Seasons are opposite between hemispheres. Earth's axial tilt creates the tropics: Tropic of Cancer (23°27'N) and Tropic of Capricorn (23°27'S). At equinoxes, sun shines on equator, giving equal day/night (12 hours each). At solstices, sun shines on tropics, creating maximum daylight in one hemisphere. For solar geometry, Earth is stationary while the sun appears to move across the celestial sphere. Two angles define sun position: (1) Azimuth - direction from north (0°=N, 90°=E, 180°=S, 270°=W), ranging 0-360°; (2) Altitude - height above horizon (0°=horizon, 90°=overhead). Solar trajectory varies significantly with latitude. At the equator, sun passes overhead (90° altitude) once yearly during summer solstice. At higher latitudes, sun never reaches 90°. At 23°27' South, sun passes overhead during summer solstice. At 40° South, sun's path is highly inclined, creating extreme seasonal differences (15h summer vs 9h winter daylight).

To determine or predict solar radiation incident on a specific location, basic geometric aspects of the sun-earth system must be known. Latitude is determined by the angle formed by a line connecting the location to Earth's center with the equatorial plane. Declination angle is the angle between the equatorial plane and the orbital plane of Earth around the Sun, varying from 0° at equinoxes to slightly over 23° at summer and winter solstices. The maximum solar elevation angle for a location and day depends on both latitude and declination, affecting opposite hemispheres (summer in southern hemisphere coincides with winter in northern hemisphere). Azimuth angle varies throughout the day at a rate of 15° per hour, being zero at solar noon, negative during morning, and positive during afternoon.

The sun's position is described using altitude (vertical angle from horizon) and azimuth (horizontal angle from north). These coordinates depend on location, date, and time. Solar noon occurs when the sun reaches its highest point, which varies by latitude. The sun's path changes dramatically between seasons: in Madrid, June 20th shows 15-hour daylight with 73° maximum altitude, while December 20th shows only 9 hours with 26° maximum altitude. In the Northern Hemisphere, the sun always moves rightward and passes through south at noon.

This video explains four fundamental electrical units: (1) Unit of electricity equals 1000 watt-hours, calculated as power × time; (2) Horsepower (HP) measures power, where 1 HP = 746 watts; (3) Ampere measures electric current, where 1 ampere = 1 coulomb per second; (4) Watt measures power, where 1 watt = 1 joule per second. These units form the foundation for understanding electrical measurements and calculations.

This lesson covers the fundamental units of electrical measurement: (1) Current (التيار) measured in Amperes (أمبير), (2) Voltage (الجهد) measured in Volts (فولت), (3) Power (القوة) measured in Watts (واتس), (4) Energy (الطاقة) measured in Watt-hours (واتس-ساعة). These units are essential for understanding and calculating electrical properties in circuits.

Electrical power equals voltage multiplied by current (P = V × I). Power is measured in watts (W), kilowatts (kW), megawatts (MW), etc. Energy is power used over time, measured in watt-hours (Wh), kilowatt-hours (kWh), megawatt-hours (MWh), etc. One kilowatt equals 1000 watts, and one kilowatt-hour equals 1000 watt-hours.

Voltage (electromotive force) is the force pushing electrons, measured in volts. One volt equals 1 joule of energy per coulomb of charge (V = W/Q). Current is the rate of charge flow, measured in amperes (1 A = 1 C/s). Charge accumulates according to Q = I × T. Voltage can exist without current, but current requires a complete circuit. Electric power is the rate of energy consumption, measured in watts (1 W = 1 J/s). Formula: P = E × I (power equals voltage times current). Power can also be expressed in horsepower (1 HP = 746 W). Electrical energy is the capacity to do work, measured in joules (SI) or kilowatt-hours (commercial unit). Energy (kWh) = Power (kW) × Time (hours). Examples: 5 kJ energy pushing 2,900 C yields 1.72 V; 4 A for 5 seconds accumulates 20 C; 6 C moving in 0.25 s equals 24 A; 300 V at 2 A yields 600 W; 1,000 W heater for 2 hours consumes 2 kWh.

Electric power (P) is the rate of energy consumption, measured in Watts (W). The formula is P = VI (Power equals Voltage times Current). Power can also be expressed as P = W/T (Work per unit time). Common units include Watt, Kilowatt (1000W), and Horsepower (1 HP = 746W). The kilowatt-hour (kWh) is the unit of electrical energy consumption, commonly known as one 'unit' of electricity. 1 kWh equals 1000 Watts used for 1 hour, or 3.6 × 10^6 Joules. This unit is used by electricity providers to bill consumers for their energy consumption.

Servo motors rotate to precise angles (0-180°) using PWM signals from Arduino. The Servo library provides attach(pin) and write(angle) methods for control. Light-dependent resistors (LDRs) measure ambient light levels through analogRead(pin), returning values 0-1023. Combining sensor input with conditional logic creates automatic systems: if lightValue > threshold, move servo to open position; else, return to closed position. This demonstrates closed-loop control where sensor feedback drives mechanical action, enabling applications like automatic blinds, light-following robots, and environmental monitoring systems.

This tutorial demonstrates how to control a servomotor (SG90 model) using a Light Dependent Resistor (LDR) sensor on an Arduino UNO board. The LDR detects ambient light intensity, and the Arduino converts this analog reading into a position value (0-180 degrees) using the formula: position = (1023 - LDR_value) / 4. The servomotor rotates proportionally to the detected light level, with higher light causing the motor to rotate toward 180 degrees and lower light returning it to 0 degrees. The hardware connections include the LDR and a 10kΩ resistor forming a voltage divider connected to analog pin A0, while the servomotor's signal wire connects to digital pin 9, with power and ground properly routed.

An automatic sun-tracking solar panel system uses an Arduino UNO microcontroller with two Light Dependent Resistors (LDRs) to detect light intensity differences, and a servo motor to rotate the solar panel toward the stronger light source; the system compares analog readings from both LDR sensors, and when the difference exceeds a predefined tolerance threshold (20 units), the servo motor adjusts its position by incrementing or decrementing the angle (from 0° to 180°) to align the solar panel with maximum sunlight exposure, thereby optimizing energy harvesting efficiency.

This video demonstrates how to automate the Chrome Dino game using Arduino, an LDR (Light Dependent Resistor) sensor, and a servo motor. The LDR detects when a cactus appears by sensing reduced light, and the servo motor presses the space bar to make the dinosaur jump. The Arduino code reads the LDR value (ranging from 0-230) and triggers the servo motor when the value drops below a threshold (around 690), then waits 150ms before resetting. The distance between the sensor and screen determines the jump timing, requiring calibration for optimal gameplay.

An automatic solar tracker system uses two LDR (Light Dependent Resistor) sensors positioned at different angles to detect light intensity variations, with an Arduino microcontroller comparing the sensor readings and controlling a servo motor to rotate the solar panel toward the light source; when light intensity differs between sensors by more than a predefined tolerance threshold (20 units), the servo motor adjusts its position by incrementing or decrementing the angle (0-180 degrees) to align the solar panel with maximum sunlight exposure, thereby optimizing energy harvesting efficiency.