Week #7 - Journal 

Then, I connected the components to my circuit and used the following pins on the Arduino:

• 5V pin: on the Arduino to the 5V positive channel of the breadboard

• VIN pin: on the Arduino to the 9V positive channel of the breadboard (for the L298N motor driver)

• GND pin: on the Arduino to the negative channel of the breadboard

• Pin 6 & 7: motor driver to control the DC motor's rotational direction

• Pin 3: echo ultrasonic sensor

• Pin 4: trig ultrasonic sensor

• Pin 2: pushbutton

• Pin 9: buzzer

• Pin 8: NeoPixel 8 LED strip

• Pin A4: SDA of the LCD screen

• Pin A5: SCL of the LCD screen

Finally, I started writing the Arduino C code to simulate some of the components in Tinkercad to make sure they were working properly.

To build the code that would be uploaded to the Arduino board, I installed 2 libraries and used their examples: the LiquidCrystal_I2C for the LCD screen and Adafruit_NeoPixel for the NeoPixel 8 LED strip. Then I defined the Arduino pins and added the ultrasonic sensor code from week 6 assignment. After that, in the void setup that runs only once at the beginning, I set the function pinMode to either input or output (the pushbutton is input_pullup). Next, in the void loop, which's a function that executes indefinitely until the power is off, I set the ultrasonic distance to 20 cm to activate the LCD screen. The LCD screen will display this sentence when activated from the ultrasonic sensor: "When you hear the beep, press to win a treat!". After that, there'll be 3 seconds delay, and the buzzer will make a beep sound. Then, if the pushbutton is pushed (low), three actions will happen simultaneously: 

1. The buzzer will make a second sound with a different tone

2. The motor will rotate in one direction for one second

3. The NeoPixel 8 LED strip will emit light and change colors (red, green, yellow, blue, none) one by one.

Finally, I compiled the code and resolved the bugs, then uploaded the code to the Arduino board and it worked perfectly.

For the enclosure, I used cardboard, a glue gun, a cutter, and a bottle cap for the DC motor to attach to the coil spring. Then, I measured the parts and components, glued cardboard parts together, and mounted the components onto the box enclosure. Finally, I powered the box and it was fully functional.

I faced 2 challenges while doing the assignment. The first challenge was writing the code for the LCD screen and the ultrasonic sensor. I used an ultrasonic sensor in week 6 assignment, but the difficult part was making it an input for the LCD. Also, installing the LiquidCrystal_I2C library for the LCD was complicated and it didn't work at all on my Mac laptop. Luckily, I figured it out with trial and error and watched the tutorial below, And the LiquidCrystal_I2C library worked fine when I installed it on a Windows laptop. I made the needed adjustments, and everything worked well.

The second challenge was mounting the components into the box. There were too many wires, the box was small, and the wires kept wrapping around the coil spring when the DC motor rotated. I had to take out all the components several times to troubleshoot the wiring. Eventually, I used the Avometer continuity test to ensure connectivity in the circuit without taking everything out of the box when there was an issue. Also, I used a lot of adhesive tape to make sure everything was in place and away from the coil spring.