autoplant/autoplant/autoplant.ino

#include <bitset>
#include <string>

#define MULTIPLEX_PINA	D5
#define MULTIPLEX_PINB	D6
#define MULTIPLEX_PINC	D7

#define ANALOG_PIN		A0

/*
000	0
001	1
010	2
011	3
100	4
101	5
110	6
111	7
*/

#define SOIL_A			0
#define SOIL_B			6
#define WATER_LEVEL_A	2
#define WATER_LEVEL_B	4


// Ref https://stackoverflow.com/a/523737/1460422
#define CHECK_BIT(var,pos) ((var) & (1<<(pos)))

int soilPin = D3;

float referenceVoltage = 3.3;



float read_analog(int channel) {
	
	const char* bin = std::bitset<8>(channel).to_string().c_str();
	
	bool b0 = bin[7] == u'1';
	bool b1 = bin[6] == u'1';
	bool b2 = bin[5] == u'1';
	
	digitalWrite(MULTIPLEX_PINA, b2);
	digitalWrite(MULTIPLEX_PINB, b1);
	digitalWrite(MULTIPLEX_PINC, b0);
	
	int rawValue = analogRead(ANALOG_PIN);
	float parsedValue = ((float)rawValue) / 1024.0 * referenceVoltage;
		
	return parsedValue;
}

void setup() {
	Serial.begin(9600);
	Serial.println("Analogue Soil Sensor Test");
	Serial.println("=========================");
	pinMode(MULTIPLEX_PINA, OUTPUT);
	pinMode(MULTIPLEX_PINB, OUTPUT);
	pinMode(MULTIPLEX_PINC, OUTPUT);
}

void loop() {
	Serial.print("SOIL_A\t");
	Serial.println(read_analog(SOIL_A));
	Serial.print("SOIL_B\t");
	Serial.println(read_analog(SOIL_B));
	Serial.print("WATER_LEVEL_A\t");
	Serial.println(read_analog(WATER_LEVEL_A));
	Serial.print("WATER_LEVEL_B\t");
	Serial.println(read_analog(WATER_LEVEL_B));
	
	Serial.println("\n\n\n\n\n");
	
	delay(5000);
}