Solar Energy lesson
You will learn:
- How solar energy is harvested from the sun
- How to program the micro:bit to measure solar energy
You will need:
- 1 micro:bit
- 1 Seenov Solar Battery with solar panel
- The sun
- 1 aligator clip
- 1 Jumper wire
- 1 computer
- 1 USB cable
Lesson duration: 15 minutes
How solar Energy Works
- The sun’s light rays hit the solar panel.
- The solar panel transforms the sun’s light into electricity to charge the lithium battery.
- The lithium battery powers the micro:bit.
What if?
What if there is too much sun?
The “Battery Charger” circuit turns off the electricity from the solar panel.
What if there is not enough sun?
The “Low battery Turn-Off” circuit turns off the “Voltage Regulator Circuit” and no more energy flows out of the battery.
Connections:
- Connect the solar panel to the solar battery.
- Connect the solar battery to the micro:bit BATTERY connector.
- Connect Battery Voltage Monitor P5 on the solar battery to the micro:bit edge connector Pin 0 .
- Connect P3 (Charger ON-OFF) on the solar battery to the micro:bit edge connector Pin 1.
- Connect the USB cable from the micro:bit to the computer.
Prerequisite
Create a program that turns on as many LED as possible, download it to the micro:bit and connect the micro:bit to the solar battery. Disconnect the USB cable and let it run for a few days to drain the battery.
Activity:
Download the program in the following section to the micro:bit. Place the solar panel face down on any surface. Do not connect the USB port on the Solar Battery. Observe the value displayed on the micro:bit LEDs. Slowly move the solar panel towards the sun and observe the change in this. Rotate the solar panel right, left, up and down and find the orientation where the maximum number appears. That is the best panel orientation where the maximum energy from the sun is converted to electricity.
Coding:
First create a variable called BatteryVoltage
Then use that variable in set “BatteryVoltage” to “analog read P0
to display you can use “show number” BatteryVoltage
insert these 2 lines of code into a forever loop.
Instead of the show number you can make a graph.
The actual battery voltage varies between 3.0V and 4.7V. It is divided by 2.4 at the monitor terminal P5. The value read by the micro:bit will be between 1.25V (3/2.4) and 1.96 V (4.7/2.4)
Conclusion
Learning to control solar power with computers like the micro:bit opens up a new , plentiful and non polluting energy source.
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