# soil_monitor.py - MicroPython on Raspberry Pi Pico
# Reads soil sensor on GP26 (ADC0) and prints raw ADC, voltage, and moisture %

from machine import ADC
import utime

# === Configuration ===
ADC_PIN = 26        # GP26 = ADC0
VREF = 3.3          # Pico ADC reference voltage (3.3V)
SAMPLE_INTERVAL = 1.0  # seconds

# Initialize ADC on GP26
adc = ADC(ADC_PIN)

def raw_to_voltage(raw):
    """Convert 16-bit raw ADC reading to voltage (0..3.3V)."""
    return (raw * VREF) / 65535.0

def voltage_to_moisture_pct(voltage):
    """Convert voltage to soil moisture % (simple linear mapping)."""
    return (voltage / VREF) * 100.0

print("=== Soil Moisture Data Logger ===")
print("Pin: GP{} (ADC0), Reference: {:.1f} V".format(ADC_PIN, VREF))
print("Raw | Voltage (V) | Moisture (%)")
print("---------------------------------")

while True:
    raw = adc.read_u16()   # raw value (0..65535)
    voltage = raw_to_voltage(raw)
    moisture_pct = voltage_to_moisture_pct(voltage)

    # Print results
    print("{:5d} | {:6.3f} V   | {:6.1f} %".format(raw, voltage, moisture_pct))

    utime.sleep(SAMPLE_INTERVAL)