Week 6

First: Simulating the Circuit

1- I opened Tinkercad in my browser.
2- Logged in using my email.
3- Started by creating a new circuit for testing

Second: Creating the Circuit
1- I searched for the components I needed:
a- Arduino UNO R3
b- Small Breadboard
c- 4 LEDs
d- 4 resistors (220 Ω each)
e- Ultrasonic Distance Sensor (4 Pins: VCC, Trig, Echo, GND)

2- I placed the 4 LEDs on the breadboard.
3- Since each LED requires only ~2V but Arduino pins provide 5V, I added a 220 Ω resistor in series with the cathode (negative leg) of each LED.
4- The other side of the resistor was connected to the ground rail with a black wire.
5- I connected the positive legs of the LEDs to the Arduino pins:

• LED1 → Pin 11

• LED2 → Pin 10

• LED3 → Pin 9

• LED4 → Pin 8

6- For the Ultrasonic Sensor:

• VCC → 5V on Arduino

• GND → Arduino Ground

• Trigger → Pin 6 

• Echo → Pin 5

Third: Coding

A- Setting the Input
1- Defined Trigger and Echo pins in the code.
2- The ultrasonic sensor sends a pulse through Trigger and receives it on Echo to measure distance.
3- Used a function readUltrasonicDistance to calculate the distance.

B- Setting the Output with Conditions
4- I used an if condition to control the LEDs.
5- If the measured distance is less than 20 cm → LEDs turn on sequentially (one after another).

C- LED Sequence
6- LED1 turns ON for 1 second, then OFF → LED2 ON, and so on until LED4.
7- If no object is detected within range, all LEDs remain OFF.

Uploading the Code to the Arduino

After completing the wiring and coding:

1- I connected my Arduino UNO to my laptop using a USB cable.
2- Opened the Arduino IDE and wrote my code.
3- From the Tools menu, I selected the correct board (Arduino UNO) and the right port.
4- Before uploading, I clicked the Verify button to check for any errors.
5- Then, I clicked the Upload button to send the code to the Arduino.
6- Within a few seconds, the circuit came to life: the ultrasonic sensor started measuring distance, and the LEDs turned on one by one according to the programmed conditions.

Practical Steps to Implement the Project in Real Life

1- Preparing the Board and Components

• I prepared an Arduino UNO, a medium breadboard, 4 LEDs (with 220Ω resistors), and an HC-SR04 ultrasonic sensor.

• I also prepared a set of jumper wires for the connections.

2- Connecting Power and Ground

1. I connected the 5V pin from the Arduino to the positive rail (+) on the breadboard.

2. I connected the GND pin from the Arduino to the ground rail (–) on the breadboard.

3. I made sure that all grounds in the circuit were unified on the same rail.

3- Placing and Wiring the LEDs

1. I placed the four LEDs on the breadboard in a row.

2. For each LED:

   • The negative leg (cathode) was connected to a 220Ω resistor, then to the ground rail.

   • The positive leg (anode) was connected to the Arduino pins as follows:

     • LED 1 → Pin D11

     • LED 2 → Pin D10

     • LED 3 → Pin D9

     • LED 4 → Pin D8

4- Placing and Wiring the Ultrasonic Sensor (HC-SR04)

1. I placed the ultrasonic sensor on the breadboard with its pins facing the Arduino.

2. The connections were:

   • VCC → 5V on the Arduino

   • GND → Ground rail on the breadboard

   • Trig → Pin D6 on the Arduino

   • Echo → Pin D5 on the Arduino

5- Double-Checking the Circuit

• I checked that each LED had a resistor in series.

• I made sure all grounds were connected properly.

• I used different wire colors (just like in the Tinkercad diagram) to avoid confusion.

6- Connecting the Arduino to the Computer

1. I connected the Arduino UNO to the laptop using a USB cable.

2. I opened the Arduino IDE software.

3. I selected the correct board (Arduino UNO) and the right port.

4. I verified the code and then uploaded it to the board.

7- Running the Project in Real Life

• Once the code was uploaded, the ultrasonic sensor started measuring distance.

• When an object (like my hand or a small car toy) came closer to the sensor:

  • The LEDs turned on one by one, depending on the distance.

• When the object moved away, the LEDs turned off again.
  
  

Problem: The first LED did not work during testing.

Solution: After checking all the connections and trying several times, I discovered that the problem was with the jumper wire itself, as it was not conducting electricity properly. Once I replaced the wire, the LED worked normally.

Other than this issue, I did not face any problems while building or running the circuit.