Circuit Diagram





The Nokia 5110 LCD operates on 3.3V, if we will connect it directly to the data pins on the Arduino then it will operate, but the lifetime of the Nokia 5110 LCD will decrease. So, if you want to use it for a longer span, then you will have to use the resistors as we used in our project.

To connect the Nokia 5110 LCD with the Arduino, make the connections for the Nokia 5110 LCD with the Arduino as follows:

Connect pin 1 on the Nokia 5110 LCD which is the reset Pin to pin 6 on the Arduino through the 10K resistor.

Connect pin 2 on the Nokia 5110 LCD which is the chip select pin to pin 7 on the Arduino through the 1K resistor.

Connect pin 3 on the Nokia 5110 LCD which is the data or command pin to the pin 5 on the Arduino through the 10K resistor.

Connect pin 4 on the Nokia 5110 LCD which is the data input pin to the pin 4 on the Arduino through the 10K resistor.

Connect pin 5 on the Nokia 5110 LCD which is the clock pin to pin 3 on the Arduino through the 10K resistor.

Connect pin 6 on the Nokia 5110 LCD which is the VCC pin to 3.3V pin on the Arduino.

Connect pin 7 on the Nokia 5110 LCD which is the LED pin to the middle pin on the 1k potentiometer through the 330 ohm resistor and connect the other two pins to the VCC and the ground.

Connect pin 8 on the Nokia 5110 LCD which is the ground pin to the GND on the Arduino.

The potentiometer used here is for increasing or decreasing the backlight of the LCD. If you want full backlight, then you can connect it directly to 5V. If you want no backlight, then connect it to ground.



After that, connect the relay module with the Arduino as follows:

Connect the VCC pin on the relay to 5V on the Arduino.

Connect the ground pin on the relay to GND on the Arduino.

Connect the IN pin to pin 8 on the Arduino.

On the other side of the relay, connect the positive end of the battery to NC on the relay and C on the relay to the positive on the solenoid Valve. Then connect the negative on the battery to the negative on the solenoid valve.



Last, connect the FC-28 soil moisture sensor to the Arduino as follows: