// ============== ESP32 VERSION (no buttons) ===================
// Reads moisture from potentiometer on GPIO34
// Displays moisture % and plant image on SSD1306 OLED
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_RESET -1
#define SCREEN_ADDRESS 0x3C
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
#define SOIL_PIN 34 // analog input from potentiometer
// Default hard-coded calibration
int dryValue = 4095; // max ADC — driest
int wetValue = 800; // in practice adjust if needed
// Plant bitmap dimensions
#define plant_width 32
#define plant_height 48
#include "plant_bitmaps.h"
void setup() {
Serial.begin(115200);
if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
Serial.println("SSD1306 allocation failed");
while (true);
}
display.clearDisplay();
display.setTextSize(1);
display.setTextColor(SSD1306_WHITE);
display.setCursor(0, 0);
display.println("Soil Monitor");
display.println("ESP32 Ready");
display.display();
delay(1000);
}
void loop() {
int soilValue = analogRead(SOIL_PIN); // 0–4095
int moisturePercent = map(soilValue, dryValue, wetValue, 0, 100);
moisturePercent = constrain(moisturePercent, 0, 100);
int imageIndex = map(moisturePercent, 0, 100, 0, 26);
imageIndex = constrain(imageIndex, 0, 26);
display.clearDisplay();
display.setCursor(0, 0);
display.setTextSize(1);
display.println("Soil Monitor");
display.setCursor(0, 16);
display.setTextSize(2);
display.print(moisturePercent);
display.println("%");
display.setCursor(0, 40);
display.setTextSize(1);
display.print("Raw:");
display.println(soilValue);
if (moisturePercent < 30) {
display.println("DRY");
} else if (moisturePercent < 60) {
display.println("OK");
} else {
display.println("WET");
}
display.drawBitmap(96, 8, plant_images[imageIndex], plant_width, plant_height, SSD1306_WHITE);
display.display();
delay(300);
}