Week #8 - Journal

Ideation

Tell us about your assignment's idea for this week. Why do you care about this idea? What inspired you? (Please include images or links to sources of inspiration)

This week idea is based on connecting the project via Bluetooth for control using a mobile phone or laptop. So, I thought about using components that I haven't used in any previous assignments, such as a fan and a temperature sensor.

The assignment idea is:

The temperature sensor reads the temperature.
When it reaches a certain level, the fan turns ON.
When the temperature drops below the threshold, the fan turns OFF.
A buzzer sounds when the fan turns ON or OFF.

Tool Chain

Which software/machines/materials did you use in the assignment? Why?

FOR Simulation Circuit

To simulate the circuit and ensure it works with the correct connections.

Electronics Tools

Breadboard

Dc Fan

Jumpers Wires

Arduino Uno

Slide Switch

Buzzer

Resisotrs

Md-BT-18

Gui on Phone

Arduino BleuControl

Design/Preparation Process

Explain the design and/or preparation process of your assignment. How did you use the tool or software to design and/or prepare your assignment before fabrication/implementation?

Design Circuit on Tinkercad:

Circuit Components:

DHT11 (Lm35 in tinkercad)
Dc Fan
Buzzer

Circuit Input:

DHT11 sensor

Circuit Actions:

Fan On
Fun Off with buzzer sound

Steps Taken:

Connected the Ground and 5V between Arduino and breadboard
Connected the DHT11 with Pin 2
Connected Buzzer with Pin 5
Connected Dc Fan with Pin3

Development/Implementation Process

Explain the development/implementation process of your assignment. How did you use the machine/tool to manufacture or implement the design of your assignment?

Build Circuit on actual Arduino and Breadboarding

I connected the circuit on a real Arduino and breadboard, following the wiring from TinkerCAD without any difficulties. Then, I connected the Bluetooth module and finally plugged it into my laptop to ensure everything was working properly.

Code

First, I displayed the DHT11 library and code in Arduino, then copied it to add the rest of the code Then, I defined the variables and set each pin as input or output according to my wiring. After that, I wrote the code:

The DHT11 sensor measures the temperature continuously.
If the temperature reaches 25°C, press '1' in the Bluetooth app to turn ON the fan.
If the temperature drops to 20°C, the buzzer will beep for a second.
After the buzzer sounds, press '2' in the Bluetooth app to turn OFF the fan.
The system repeats this process every 1 second.

From DHT11 Library

Arduino.ino code

Code

WhatsApp Video 2025-02-25 at 16.42.23_9cc6cad3.mp4

Community of Learning

Did you ask for feedback? What are the ideas that others have contributed or suggested? What was someone else’s idea that you built upon? How did you help your peers? How did your peers help you?

Title of Media

Overcoming Challenges

When you got stuck, what/who did you turn to? At what point did you have to pause to research or learn more before moving on? What are some mistakes, pitfalls, or challenges that others can avoid if they were doing this assignment?

When I first connected the Bluetooth module, it wasn’t connecting from the mobile phone and kept showing "Couldn't connect". Then I remembered that I had faced this issue before, and it was because the RXD pin of the Bluetooth module receives a voltage lower than 5V. So, I connected a voltage divider using two 1kΩ resistors, and it worked.

voltage divider Wiring

RXD Use 3.3v

Final Project

How can you use the skills and knowledge that you've acquired this week in your final project?