Lesson 7: Solar Panel Obstruction Impact Exploration and Automatic Cleaning System
PREPARATION
ENGAGE
Through brainstorming and guided Q&A, review previous knowledge and arouse students' curiosity.
Core Teaching Steps:
Brainstorming: Real-world Issues:
Discuss scenarios causing voltage drop and power reduction in solar panels:
1. Dust/sand accumulation on the panel surface
2. Partial obstruction (e.g., leaves, bird droppings)
3. Cloudy weather or reduced sunlight intensity
4. Physical damage to the panel (cracks, scratches)
5. Aging of solar cells over time
Guided Thinking:
Pose questions:
1.In desert environments, how does sand/gravel coverage affect the power generation efficiency of solar panels?
(E.g., Reduces light absorption, may cause hotspots or uneven heating.)
2.Based on previous knowledge, what methods can be used to monitor solar power generation efficiency in real time?
(E.g., Voltage/current sensors, IoT platforms like SIoT.)
3.How to detect the coverage level in real time and trigger automatic cleaning?
(E.g., Set voltage thresholds, use SIoT to monitor data and activate fans when anomalies are detected.)
EXPLORE
Explore the relationship between solar panel obstruction and power generation efficiency.
Core Teaching Steps:
connection:
SIoT Setup Guide:
Please finish this step by referring the instructions from lesson 6.
Coding:
If “successful” does not appear on the screen, press the reset button until it displays “successful”.
Real-time Data Monitoring and Export:
1.View Data
Go to "Device List" on SIoT web interface, click "View Messages" for K10/001, and enable "Auto-refresh messages".
2.Export to Excel
Click "Export Excel" (at the top-right of the message list) and save as Excel.
3.Data Record
The exported file includes timestamp and voltage data, e.g.:
Experiment Design: Cardboard Obstruction Simulation:
Group Experiments:
Group 1: No obstruction
Group 2: 1/2 cardboard obstruction
Group 3: Full obstruction
Data Export Rules:
After each experiment, export Excel files named ObstructionLevel_GroupNumber.xlsx, e.g.:
EXPLAIN
Process Data and Calculate Averages in Excel.
Core Teaching Steps:
Import Data to Excel::
Open Excel, go to "File" → "Open", and select the exported .xlsx file.
Data Cleaning (Optional):
Remove invalid rows (e.g., null values, abnormal voltages), keeping time and voltage columns.
Calculate Averages:
Step 1: Select a cell
Enter the formula =AVERAGE(C:C) in a blank cell next to the voltage column (assuming voltage is in column B).
Step 2: View results
The formula calculates the average of all voltage values, e.g.:
Step 3: Group comparison
Calculate averages for different obstruction levels, e.g:
Principle Summary:
The voltage data exported from SIoT shows an inverse relationship between solar panel power generation efficiency and obstruction level. The more a solar panel is obstructed, the lower its power generation efficiency.
Threshold Setting:
Prepare for the next challenge: Instruct students to consider how to set the alarm threshold. For example, use the average voltage without obstruction (e.g., 748.75mV) as the baseline and set the alarm threshold at 375mV (approximately 50% efficiency).
CHALLENGE
Design an SIoT-Based Automatic & Remote Cleaning System.
Core Teaching Steps:
Connection:
Coding(Automatic Cleaning System):
Coding(Remote Cleaning System):
Experimental Validation Steps:
Automatic Mode Test:
Cover solar panel with cardboard → Voltage drops < 375mV → Fan auto-starts.
Remove cardboard → Voltage rises ≥ 600mV → Fan auto-stops.
Remote Control Test:
Send ->on via SIoT → Verify fan activation.
Send ->off via SIoT → Verify fan deactivation.
Critical Thinking Questions:
1.Why use both automatic and remote control modes?
2.How to optimize fan operation to save energy (e.g., pulse cleaning instead of continuous operation)?
CONCLUSION
The teacher will now summarize the lesson and guide the students to disconnect and neatly pack away all equipment before returning it.
Program-L7.zip 
