Month: November 2025

After much thought, brainstorming, and research, I decided to create a circuit for a fan because quite frankly, my room gets very warm (even during winter time). Of course, without requiring the necessary skills, I would have to learn step-by-step how to make this circuit.

Before attempting to create the fan, I had to learn some basics. I watched a few videos, here is one that helped me the most:

After watching the video and inspecting examples online, I got working. As Mr.Crompton had said in a previous class, there was something called a breadboard; a board used to connect electronic components (wires, resistors, capacitors, and coils) allowing for the conductivity of various experiments and projects. The breadboard is like a soccer field, and the electronic components are like the players. All the players are working together to ensure conductive success (in this case activating the fan).

The breadboard looks like this:

Beside the breadboard (connected via wires) is an Arduino UNO, which looks like this (will elaborate on all the pieces later on):

Connected to the breadboard is an L293D motor driver chip:

And a DC motor (the fan practically):

What does each component do?

Breadboard:

Arduino UNO: The Arduino UNO is like the brain or head of the whole circuit. It is the component that processes all the code I write, which helps the circuit run smoother and operate more efficiently. It is also responsible for sending signals and giving directions to other components like LEDs, motors, or buzzers to perform actions. In my circuit, the Arduino sends a signal to turn my fan on or off.

L293D: The L293D’s job is controlling larger currents and voltages than the Arduino can handle directly. Its many ‘hands’ (as shown by the picture), otherwise known as its input, output, power, and enable pins, all connect wires to different places within the circuit. The wires connected to the L293D in my circuit are meant to direct electricity from the power source to my DC motor on the Arduino’s instructions.

DC Motor: The DC Motor is the component that actually uses the electricity, turning the energy into motion. The DC motor is like the finish line of a marathon and the other working components are like the coaches and guides along the track, making sure the electricity (the runner) reaches the motor safely and fairly quickly. In my circuit, the DC motor is the fan; the component that actually uses the electricity in order to serve its purpose.

TMP: The TMP is the component that measures temperature and activates the fan accordingly. For example, if my room were to become warmer, the TMP would activate other components (and wires), turning on the DC Motor (the fan).

Here is what my circuit looks like (if you want to look at it and experiment yourself, here is the link): https://www.tinkercad.com/things/f53kffusogK-magnificent-lappi/editel?returnTo=https%3A%2F%2Fwww.tinkercad.com%2Fdashboard&sharecode=DcELQL0B3qmmEK7NdFA38dnDWPhRtq6y5R_xpi162y0

As we can see, all the previously mentioned components have a role in my circuit. We can see the Arduino Uno (far left), the breadboard (middle), the L293D (attached to the middle of the breadboard), the DC Motor (top middle), and the TMP (middle left).

Additionally, all the wires (all colour coded based on different positions/purpose) can be seen attached to the different components.

Although not previously mentioned, I have added code to the circuit so everything can run without additional unnecessary parts. I will elaborate more on my code later on.

Here are the colour codes for all of the wires:

Blue = Connected to the L293D

Red = Connected within the breadboard

Green = Connected to the Arduino UNO/the DC Motor

Once I press the “Start simulation” button (top right of the circuit page), the Arduino UNO activates, plugging what I believe is a USB cable into the machine. This activates everything connected to it, which is where the wires come into play.

Here is a picture of the activated Arduino UNO:

Once the Arduino is activated, it releases electricity/power through the connected wires into the components within the breadboard.

The blue wires all connect to the L293D, which was mentioned previously to be the controller of larger currents and voltages.

As you can see in the image below, the L293D possesses many pins or ‘hands’, two of which connect directly to the DC Motor and one connected to the Arduino UNO. The connected wires allow the component to direct the electricity from the power source directly to the DC motor.

All the other seemingly ‘useless’ wires also play a major role in my circuit, as they prevent the L293D from not working or from exploding? Here’s what I mean:

Circuit with breadboard wires (first image) vs Circuit without breadboard wires (second image):

I discovered this by simply experimenting and removing wires that I initially thought were useless, until realizing that they were equally important as the ones connected to the L293D. After researching the purpose of these wires, it appears that they help provide power to the different parts of my circuit, especially the L293D motor driver, which must have its own power connections to work. The red wires distribute power throughout the breadboard so that the L293D and the motor can actually receive electricity, serving a purpose I once questioned.

The TMP plays a major role in my circuit, as it allows the fan to only be activated when a certain temperature is present.

First, the TMP measures the temperature and sends a voltage to the Arduino Uno. Then, the Arduino Uno reads the temperature and decides when to run the DC Motor. The L293D reads the Arduino’s signal and powers the DC Motor with the 9V battery. The fans only turns on if the temperature is high enough.

I added some code to the circuit in order to make less of a mess on the breadboard and make everything easier.

The first part of my code involves these three wires that go from the Arduino to the L293D pins:

int en1 = 5; // PWM pin → L293D Enable 1 (controls motor speed)
int in1 = 4; // Digital pin → L293D Input 1 (controls direction)
int in2 = 3; // Digital pin → L293D Input 2 (controls direction)

These match the L293D’s job:

EN1 = speed control (must be HIGH/PWM for motor to run)

IN1 + IN2 = direction control

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

My next part of the code tells the Arduino:

“I will be sending signals out of pins 3, 4, and 5.”

void setup() {
pinMode(en1, OUTPUT);
pinMode(in1, OUTPUT);
pinMode(in2, OUTPUT);
}

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

The next part of code tells the motor driver to spin the motor forward

digitalWrite(in1, HIGH);
digitalWrite(in2, LOW);

On the L293D, this combo means:

IN1 = HIGH

IN2 = LOW

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Next, EN1 (the ‘enable 1’ pin on the L293D) receives a PWM signal (Pulse Width Modulation).

Range is 0–255

255 = full power

200 = medium-fast

0 = stopped

This controls how much power the L293D sends to the motor.

So here, the motor runs at speed 200.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Both of the “delay” codes don’t do much, other than basically telling the motor to keep running.

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

Finally, the ‘analog’ code tells the motor to stop running by cutting out power.

analogWrite(en1, 0);

void loop() {
int reading = analogRead(tempPin);
float voltage = reading * (5.0 / 1023.0);
float temperatureC = (voltage – 0.5) * 100.0; // TMP36 formula

Serial.print(“Temperature: “);
Serial.println(temperatureC);

if (temperatureC > 30.0) {
// Turn fan ON — clockwise direction
digitalWrite(motorPin1, HIGH);
digitalWrite(motorPin2, LOW);
analogWrite(enablePin, 255); // full speed
} else if (temperatureC < 25.0) {
// Turn fan OFF
analogWrite(enablePin, 0);
}

delay(500);
}

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

This code connects back to the temperature correlating to the DC motor, and how the temperature has to be high enough for the fan to activate.

Arduino UNO

Breadboard

Wires

L293D

DC Motor

Ai usage was minimal. Used it to help me come up with ideas and explain parts of circuits (not necessarily the ones I used in my circuit) and their purposes. Also helped me elaborate on the red wires and their purpose.

Here is a transcript of our chat(s)(on a google doc):

https://docs.google.com/document/d/1V-SQy_JlMjg0pC4guigWR4H_TfZ-3S7ViiJGEYKKPYQ/edit?tab=t.0

According to AI, every wire has a purpose which is something I learned along the way.

How big is the universe?

That is a question many individuals, specifically ones in the space industry, ask themselves. Who knows how many other planets there are in our infinitely expansive universe.

Are there any planets, other than earth, that can be inhabited?

That is another question that many contemplate upon. Can any planets become “liveable”?

In this Fusion/Science project, we are tasked with finding a celestial body (planet, moon, exoplanet, etc) that has hints of habitability and can become habitable by humans. Along with the task of finding an inhabitable astronomical body, we are also tasked with creating a vehicle prototype that could survive the terrain and environment of our chosen planet.

The celestial body I chose was Trappist-1e.

It is a red dwarf exoplanet that resides within the “Trappist 1 system”, a star system 40 light years away from earth and approximately 800,000 years away using current technology. Discovered in 2017, this exoplanet is considered one of the most Earth-like planets found to date due to its gravity, temperature, and physical appearance all being fairly similar to earth’s.

Extra details:

Earth’s Gravity = 9.8m/s^2

Trappist-1e Gravity = 9.12m/s^2

Many opportunities are present on my new home planet.

Research suggests that Trappist-1e orbits in its star’s habitable zone; the region around a star (in this case Trappist-1) where temperatures are suitable for liquid water to exist. Considering how Trappist-1e is the right distance from its star, it could potentially support life and contain liquid water.

Not only is Trappist-1e’s size and gravity similar to earth’s, its mass and density also appear similar to earth’s as well. According to scientists, Trappist-1e has a mass and density that suggests a rocky-ish composition, quite similar to earth’s. If true, this would allow humans to easily adapt to the exoplanet’s environment (unless other challenges exist which is elaborated on later).

Although there are many opportunities that suggest possible inhabitability, there are also many confirmed and unconfirmed factors that could pose challenges.

As mentioned previously, Trappist-1e lies within its star’s habitable zone. However, one side of the exoplanet is always facing its star, “Trappist 1”, while the other side faces away from the star. This causes extreme temperature contrasts between the day and night sides, which poses as a threat to any living thing on the planet. Hypothetically, if humans were to arrive on the planet’s “hot side”, they would be arriving on land with temperatures averaging at 275°C. The “cold side” has an average temperature of around -60 °C.

An unknown factor is Trappist-1e’s atmosphere. We have’t figured out yet whether Trappist-1e has a protective atmosphere or not, or if it’s been stripped away.

A thick, carbon dioxide dominated atmosphere like Venus or Saturn has been turned down by the “James Webb Space Telescope”. Here is a source elaborating more thoroughly on their findings and research: https://news.mit.edu/2025/study-finds-habitable-zone-planet-unlikely-have-venus-or-mars-like-atmosphere-0908

There is a possibility that this exoplanet possesses a secondary atmosphere filled and made with heavier gases such as nitrogen. There is also a possibility that Trappist-1e has no atmosphere at all, which means it experiences frequent extreme temperature swings, possesses no breathable air for life, and is exposed to radiation and vulnerable from impacts within space.

Due to the possibility of no atmosphere, we have to reconsider multiple factors for our vehicle design.

Our vehicle has to be resistant against radiation and will be required to have protective layers against the solar flares and cosmic radiation from Trappist-1e’s star, Trappist-1. Of course, if my exoplanet possesses a substantial atmosphere, these factors would be less critical as the atmosphere would reduce the amount of radiation reaching the surface. Otherwise, lots of exposure to radiation would pose a huge threat to both the vehicle and the person inside (don’t think there would an individual in the vehicle but if there was

As previously stated, the planet possesses extreme temperatures contrasting between the day and night. This means the vehicle would need adaptive heating and cooling systems for both contrasting sides of the exoplanet.

My vehicle will likely rely on nuclear, geothermal, or advanced solar power. Trappist-1e is a red dwarf exoplanet and emits infrared light. Unfortunately, standard solar panels cannot convert infrared light into electricity, which is why we would need advanced solar panels that can convert infrared light into electricity effectively.

Due to the suggested terrain of Trappist-1e (rocky composition), the vehicle will likely have wheels that can quickly traverse the exoplanet and easily stick to the surface without falling over. It is unlikely that the vehicle will float away as Trappist-1e’s gravity is fairly similar to earth’s. However, in the likely event that the planet’s surface is extremely uneven, my vehicle would need strong traction and, if necessary, implemented AI assisted navigation.

Scientists and astronomers have never physically visited Trappist-1e due to it being trillions of miles away from earth. However, we do know a surprising amount about it because of many years of detailed astronomical research and something called “the transit method”.

“The transit method”? What’s that? Apparently, it is an technique used by scientists and astronomers to detect planets outside of our solar system. As of November 10th 2025, over 4,400 exoplanets have been found using this method, which is quite a significant amount. When a planet/exoplanet passes in front of its host star (in this case Trappist-1e in front of Trappist-1), it blocks a small amount of the star’s light, causing a drop in the star’s brightness. Using this slight change in brightness, scientists have been able to determine Trappist-1e’s orbit, size, and whether it lies in the habitable zone (which it does).

NASA elaborates on the method and provides visuals: https://science.nasa.gov/exoplanets/whats-a-transit

Additionally, scientists have been able to use advanced computer modelling and simulations (from the knowledge they already possessed thanks to the transit method) to find the mass of Trappist-1e. One of the most important tools is “Transit Timing Variations”, otherwise known as TTVs.

Tug of war is extremely popular in space, especially in the Trappist star system. The exoplanets within this star system are naturally packed tightly and closely together, which causes them to pull on each other due to gravitational force. This pull of gravity can cause changes in when the exoplanets cross in front of their star, Trappist-1. These variations and change help astronomers calculate the mass of Trappist-1e and understand how the other exoplanets in the system influence each other through gravity.

This website helped me understand it much more thoroughly: https://www.planetary.org/articles/timing-variations

I attempted to use minimal AI and rely on outside sources to fully educate me. However, for building the vehicle prototype, I asked AI how radiation and no atmosphere could possibly influence vehicle precautions in outer space, and how Trappist-1e’s environment might also require specific precautions as well.

Full link to our conversation: https://docs.google.com/document/d/17uuZfIacMdGzRsV9q9geOlx5Xt_jCt8W4O5dDgT7zTg/edit?tab=t.0

Here are all the sources I used for gaining the information I needed:

Matthew W.(22.4.25).”Will we know if TRAPPIST-1e has life?”.Universe Today.https://www.universetoday.com/articles/will-we-know-if-trappist-1e-has-life

MIT News.(Date N/A).”Study finds exoplanet TRAPPIST-1e is unlikely to have a Venus or Mars-like atmosphere”.https://news.mit.edu/2025/study-finds-habitable-zone-planet-unlikely-have-venus-or-mars-like-atmosphere-0908

NASA Science.(8.11.25).”Whats a Transit?”.https://science.nasa.gov/exoplanets/whats-a-transit/

NASA Science.(7.7.25).”TRAPPIST-1 e”.https://science.nasa.gov/exoplanet-catalog/trappist-1-e/

NASA Science.(8.9.25).”NASA Webb Looks at Earth-Sized, Habitable-Zone Exoplanet TRAPPIST-1 e”. https://science.nasa.gov/missions/webb/nasa-webb-looks-at-earth-sized-habitable-zone-exoplanet-trappist-1-e/

NASA Science.(4.2.25).”Largest Batch of Earth-size Habitable Zone Planets Found Orbiting TRAPPIST-1″.https://science.nasa.gov/exoplanets/trappist1/

The Planetary Society.(Date N/A).”Timing Variations”.https://www.planetary.org/articles/timing-variations