Week 6

Light Follower

My task this week is to create Build and Program a smart circuit using an Arduino UNO which reads a signal from an LDR Photoresistor to control a servo motor to direct it to the sun using Code Blocks

I'll use the Tinkercad web app to simulate and test the circuit before building the prototype with cardboard

Then copy the code to real Arduino UNO board using Arduino IDE software

join me in the upcoming steps to learn more about how I accomplished this task.

In this project, I'll use the following components

2 LDR photoresistor
2 resistors 1K Ohm
1 Servo motor
1 small Breadboard
1 Arduino board
some wires for connection

In this step, I'll connect the photoresistor with GND and 5V pins to the Arduino and the ANALOG IN input A5

Note: the analog input for the photoresistor scale is ( 0,1023)

The Next step is, connecting the servo motor with GND and 5V pins and connecting the servo motor signal pin to the analog output pin " pin 3"

Note: the analog output has the sign ( ~ ) beside it

Now let's test the coding part before installing the rest of the photoresistors 🫣

to do that click on the code button at the top right of the screen

Because we used a photoresistor as an input, we will first choose an input, then read the analog pin, then choose A5 pin

Now from the Math section we will choose the comparison function to set the condition for the photoresistor

I will set the condition as greater than 500, action will happen

and from the output section choose the action that will happen to the servo motor

set the pin to 3 and the action will be rotating for 45 degree

Now from the control section insert the " If, Then, Else " function, then insert the input and output previous function as shown on the left image

then insert 1 sec wait after it

finally at the else set the servo motor to 0 degrees if the photo resistor read is lower than 500

Now let's test our simulation circuit

from the top right click on start simulation, then change the light brightness on the photoresistor

As you can see the servo moved 45 degrees

To try it by yourself click on the next button 👇🏽

Tinkercad simulation

Now let's install the other photoresistor and connect it to the second analog input A4 to make it rotate to the other side

for sure I tried to replicate the code for the other pin A4

But it didn't work 😭

So for this challenge, I had to start coding using blocks again from scratch

I Used the function AND from the math section to set each condition for each status

as you can see in the final code

If the light at the left sensor the servo motor will rotate 45 degrees
If the light is at the right sensor the servo motor will rotate 135 degrees
If the light at both sensors the servo motor will rotate 90 degrees
If there is no light on sensors the servo motor will stay still " 0 degrees"

As you can see the simulation works perfectly 🥳

and you can try it from here 👇🏽

Tinkercad simulation

to copy the code to the Arduino board

click on the code button
choose blocks + Text
Select the text and copy it

But the challenge I don't have all these components in my provided basic kit and the servo motor was broken 😭😭😭

So I have to start again with another sens

I'll use the LDR sensor and I'm going to simulate it with the PIR sensor on Tinkercad

The LDR sensor that will be used as the input device has 4 pins

VCC, connected to the voltage pin
GND, connected to the ground pin
DO, digital pin, and connected to digital input
AO, Analog pin, and connected to the analog input pin

we will use the digital pin DO in our device and will be connected to pins 9 & 10

The Servo motor that will be used as the action device has 3 pins

Signal, for the signal and its analog signal and will be connected to pin 11
GND, will be connected with ( - )
VCC, will be connected with ( + )

Then I changed all input blocks from read analog pin to read digital pin, and the digital pin didn't need to enter value, Just HIGH and LOW

After that

copy the code again to past it to Arduino IDE

Now connect the Arduino to your PC
from the tool menu choose port
your board should appear in the serial port section as shown in the left image
delete any code shown in the code area
past your code
click on the upload button as shown in the top image
you will see an" Uploading Done " message if everything is OK

Arduino .ino Code

Arduino .ino Modified Code

In the next step we will try to build the physical circuit using these components

Light Follower.mp4

As you can see it works perfectly as the simulation

Next Project

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