make a temperature, humidity and differential pressure system using 2004 lcd

hello friends,
i am new in the arduino section and want to make a temperature, humidity and differential pressure reading guide with 2004 lcd (not I2c) , one DS3231, ads1115 (0X4A) with mpxv5004DP sensor on A0 port of ads1115, HTU21D (for temperature and Rh), infrared receiver HS0038A (for set menu using remote) and arduino nano.
i want to make this with a menu function in it for change the values, like set date and time and differential pressure in Pa or mmwc, temperature in C or F, and offset values for calibration purpose.
I don’t know everything or something about programming. i found a lib for lcd menu which is LCDmenuLib.h

from which i edit some function but don’t know what i do next please help me for enabling and desabling the menu, i want to make this just like a product which has functions and working correctly with them.
also i want to know can we connect more then one arduino nano(more then 10 or 100) on rs485 cable in serial to take the data in PC, which software you suggest for reading temperature, humidity and differential pressure data saperately in non editable format.

LCDML_CONTROL.ino (17.1 KB)

LCDML_DISP.ino (2.95 KB)

LCDML_FUNC_BACKEND.ino (1.12 KB)

LCDML_FUNC_DISP.ino (5.56 KB)

LCDML_liquidcrystal01.ino (7.75 KB)

Is this "academic" work where you have been given a very specific set of rules about the solution or are you free to choose ? My tendency would be to look to integrate your platform with a WLAN interface which would allow you to transfer data do the configuration/ setting of time/date and other parameters.

Anyway, what ever route you go, you have to think about the user interface and how you are going to present the options and how you are going to accept data input from the user, and how you are going to process that input. That is a paper exercise which you should complete before writing a single line of code.

If you do use an LCD display, pay couple of $ to get an I2C backpack so you have a chance of having enough pins free for other peripherals-

actually i have made the hardware arrangements, ads1115, htu21d and ds3231 are connected on i2c interface pin, and 8pins are used by display with brightness and contrast, and one is used by IR receiver other pins are free. this is just for understand the microcontroller and it's accuracy and limits, i want to develop this small prototype as i seen in the pharacuitical industries.

I second the i2c backpack suggestion. Would make your circuit much simpler & free up many Arduino pins.

What are you measuring the pressure of? If it is the barometric/atmospheric? If so, you could replace the htu21 with a bme280, which measures temp, Rh and pressure.

Hey friend,
Actually I am using differential pressure sensor, used in magnahallic gauge, for show differential pressure between two rooms so I choose mpxv5004dp also it 's range is about 0 to 3.92 kpa and I want a resolution of one pa so I use adc.