Published May 17, 2020

PlantAirium

For my school education I decided to build a Plant terrarium where you can control humidity, light and temperature.

IntermediateWork in progress572

Things used in this project

Hardware components

Arduino UNO

DHT11 Temperature & Humidity Sensor (4 pins)

Jumper wires (generic)

Breadboard (generic)

DFRobot I2C 16x2 Arduino LCD Display Module

Software apps and online services

Arduino IDE

Story

For my minor we had the Exhibition Project were we had to come up with a project that challenges us.We had to set a goal and I choose to build a controllable plant terrarium. In this terrarium I want imitate a south American climate. This means in need to be able to control the humidity, temperature and light.

In order to get to know what is going on inside the terrarium I need to make the temperature and humidity that is inside visible. For this I choose to buy a DHT11 which is a temperature and humidity sensor. Furthermore I bought an LCD display which later on shows the output of the DHT11 sensor. Bot of these components will be connected to the Arduino uno.

Step 1
The first step i took was ordering some components of my plant terrarium. After a talk to my teacher i decided to order the DHT11 temperature and humidity sensor and a LCD Display with the I2c component. The I2c connector makes it easier to connect the display to the arduino because you only need to connect 4 pins instead of one and a potentiometer is already build in.
Before connecting i made this friztzing schematic.

Schematic 1

Afterwards I connected the I2C to the LCD.
The I connected the I2c LCD display to my Arduino with the help of the Jumper wires. I connected them this way : GND > GND
VCC > 5V
SDA > A4
SCA > A5

The next step i made was connecting the DHT11 to the Arduino.
I connected them this way : GND > GND
VCC > 5V
MOSI > Data

Afterwards i uploaded my code to my Arduino.

I2c LCD display with dht 11 connected

//infinite Xpro
// firstly need to add i2c library 

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);  // set the LCD address to 0x27 for a 16 chars and 2 line display 
byte degree_symbol[8] = 
              {
                0b00111,
                0b00101,
                0b00111,
                0b00000,
                0b00000,
                0b00000,
                0b00000,
                0b00000
              };
int gate=11; 
volatile unsigned long duration=0;
unsigned char i[5];
unsigned int j[40];
unsigned char value=0;
unsigned answer=0;
int z=0;
int b=1;
void setup() 
{
 lcd.init();                       // initialize the lcd
 lcd.init();
 lcd.backlight(); 
 lcd.print("Temp = ");
 lcd.setCursor(0,1);
 lcd.print("Humidity = ");
 lcd.createChar(1, degree_symbol);
 lcd.setCursor(9,0);
 lcd.write(1);
 lcd.print("C");
 lcd.setCursor(13,1);
 lcd.print("%");
}

void loop() 
{

 delay(1000);
 while(1)
 {
  delay(1000);
  pinMode(gate,OUTPUT);
  digitalWrite(gate,LOW);
  delay(20);
  digitalWrite(gate,HIGH);
  pinMode(gate,INPUT_PULLUP);//by default it will become high due to internal pull up
 // delayMicroseconds(40);

  
  duration=pulseIn(gate, LOW);
  if(duration <= 84 && duration >= 72)
  {
      while(1)
      {
        duration=pulseIn(gate, HIGH);
        
        if(duration <= 26 && duration >= 20){
        value=0;}
        
        else if(duration <= 74 && duration >= 65){
        value=1;}
        
        else if(z==40){
        break;}
        
        i[z/8]|=value<<(7- (z%8));
        j[z]=value;
        z++;
      }
    }
answer=i[0]+i[1]+i[2]+i[3];

if(answer==i[4] && answer!=0)
{
lcd.setCursor(7,0);
lcd.print(i[2]);
lcd.setCursor(11,1);
lcd.print(i[0]);
}

z=0;
i[0]=i[1]=i[2]=i[3]=i[4]=0;
 }
}