Question 3

Construct a system for below home garden.

• I2C Master side controls the water pump and water valves.

• All I2C slaves are on same bus, collects Moisture data individually.

• I2C master collects Moisture data every 5 seconds and runs the motor for 2 seconds if moisture level is low, enabling the required valve only.

Water Pump- 28VDC, 500mA
Water Valve- 12VDC, 300mA (Normally closed.)

Answers

• Method 1

Code

int val = 0; 
int soilPin = A0;
int soilPower = 7; // for sensor power to prevent corrosion of the sensor 

void setup(){
	Serial.begin(9600); 
	pinMode(soilPower, OUTPUT);
	digitalWrite(soilPower, LOW);
}

void loop(){
	Serial.print("Soil Moisture = ");    
	delay(1000);//take a reading every second
	digitalWrite(soilPower, HIGH);// turn on the sensor
	delay(10);
	val = analogRead(soilPin); 
	digitalWrite(soi lPower, LOW);//turn off the sensor
	Serial.print(val);
}

Ans

Requirements

• I2C Master controls the water pump
• I2C Master controls the water values
• All I2C will be on same bus

Water Pump- 28VDC, 500mA
Water Valve- 12VDC, 300mA (Normally closed.)

1. Water Pump

2. Water Valve

Method 1

So i have to make the I2C as master using

Receiver Code

Initial Codes

1. Just read

// Receiver Code
#incude <Wire.h>
int x = 0;

void setup(){
	Serial.begin(9600); 
	Wire.begin();
}
void loop() {
	Wire.requestFrom(8, 6);    // request 6 bytes from peripheral device #8
	while (Wire.available()) { 
		char c = Wire.read(); // receive a byte as character
		Serial.print(c);         // print the character
		}
	delay(500);
}

2. Multi slave

#include <Wire.h>
#include <stdio.h>
#include <stdlib.h>

uint8_t SLAVE_1_ADDR = 0x10;
uint8_t SLAVE_2_ADDR = 0x11;
uint8_t SLAVE_3_ADDR = 0x12;
#define MESSAGE_SIZE 5
int _index=0;

float float_valueFromOne,float_valueFromTwo,float_valueFromThree;

float get_data(uint8_t _addr){
  char _message[MESSAGE_SIZE];
  Wire.requestFrom(_addr,MESSAGE_SIZE);
  _index  = 0; 
  while (Wire.available()){
    _message[_index] = Wire.read();
    ++_index;
 } 
   return atof(_message);
}
void setup() {
  Serial.begin(9600);
  Wire.begin(); 
}

void loop() {
  float_valueFromOne = get_data(SLAVE_1_ADDR);
  float_valueFromTwo = get_data(SLAVE_2_ADDR);
  float_valueFromThree = get_data(SLAVE_3_ADDR);
  
  Serial.println("Value From One: " + String(float_valueFromOne));
  Serial.println("Value From Two: " + String(float_valueFromTwo));
  Serial.println("Value From Three: " + String(float_valueFromThree));
  delay(1000);
}

Sender Code

1. Single Slave

// Sender Code

#include <Wire.h>
void setup() {
	Wire.begin(8); // join i2c address 8 i think it must be uniqe to every device
	Wire.onRequest(requestEvent);
}
void loop() {
	delay(100);
}
void requestEvent() {
	Wire.write("10"); // respond with message of 6 bytes
  // as expected by master
}

2. Multi slave

// Slave 1
#include <Wire.h>
uint8_t myAddress = 0x10;
void setup() {
 	Wire.begin(myAddress);
	Wire.onRequest(requestThen);
}
void requestThen(){
	Wire.write("543.2");
}
void loop(){
	delay(100);
}

// Slave 2
#include <Wire.h>
uint8_t myAddress = 0x11;
void setup() {
 	Wire.begin(myAddress);
	Wire.onRequest(requestThen);
}
void requestThen(){
	Wire.write("555.5");
}
void loop(){
	delay(100);
}

// Slave 1
#include <Wire.h>
uint8_t myAddress = 0x12;
void setup() {
 	Wire.begin(myAddress);
	Wire.onRequest(requestThen);
}
void requestThen(){
	Wire.write("444.4");
}
void loop(){
	delay(100);
}

Stes

1. created a program that communicates with multiple slaves ⏫
2. Now interface the moisture sensor
3. Share the moisture value with the Master and let the master decide

Ans