Raindrop Detection

🎮 Display the Raw Sensor Reading

Goal

Read the raindrop sensor and display its raw analog value on the PC.

Concepts

Analog Input · ADC · Water Detection · Loop · Serial Output

import machine  # Controls the board hardware
import time     # Controls pauses and timing

# Sets up GPIO2 as an analog input for the rain sensor
# GPIO2 corresponds to A0 on the Sensor Shield V5.0
adc2 = machine.ADC(machine.Pin(2))

adc2.atten(machine.ADC.ATTN_11DB)  # Sets the analog input range

while True:  # Repeats forever

    water = adc2.read_u16()  # Reads the sensor value

    print(water)  # Sends the raw value to the PC

    time.sleep(0.5)  # Waits before reading again

🎮 Dry or Wet

Goal

Interpret the sensor reading and display Dry or Wet on the PC.

Concepts

Analog Input · Threshold · If/Else · Classification · Serial Output

import machine  # Controls the board hardware
import time     # Controls pauses and timing

# Sets up GPIO2 as an analog input for the rain sensor
# GPIO2 corresponds to A0 on the Sensor Shield V5.0
adc2 = machine.ADC(machine.Pin(2))

adc2.atten(machine.ADC.ATTN_11DB)  # Sets the analog input range

threshold = 32768  # Sets the wet/dry threshold

while True:  # Repeats forever

    water = adc2.read_u16()  # Reads the sensor value

    if water < threshold:  # Checks if water is detected
        print('Wet')  # Reports a wet sensor

    else:  # Runs when the sensor is dry
        print('Dry')  # Reports a dry sensor

    time.sleep(0.5)  # Waits before reading again

🎮 Detect Dry to Wet

Goal

Detect when the sensor changes from dry to wet and report Water detected only when that transition happens.

Concepts

Analog Input · Threshold · Variables · State Change · Serial

import machine  # Controls the board hardware
import time     # Controls pauses and timing

# Sets up GPIO2 as an analog input for the rain sensor
# GPIO2 corresponds to A0 on the Sensor Shield V5.0
adc2 = machine.ADC(machine.Pin(2))

adc2.atten(machine.ADC.ATTN_11DB)  # Sets the analog input range

threshold = 32768  # Sets the wet/dry threshold

last_state = 'Dry'  # Stores the previous sensor state

while True:  # Repeats forever

    water = adc2.read_u16()  # Reads the sensor value

    if water < threshold:  # Checks if the sensor is wet
        state = 'Wet'  # Saves the wet state

    else:  # Runs when the sensor is dry
        state = 'Dry'  # Saves the dry state

    if state == 'Wet' and last_state == 'Dry':  # Checks for a new wet event
        print('Water detected')  # Reports the new detection

    last_state = state  # Saves the current state

    time.sleep(0.1)  # Waits before reading again

🎮 Measure How Long Water Is Detected

Goal

Measure how long the sensor remains wet and display the duration on the PC.

Concepts

Analog Input · Threshold · Timing · Variables · Serial Output

import machine  # Controls the board hardware
import time     # Controls pauses and timing

# Sets up GPIO2 as an analog input for the rain sensor
# GPIO2 corresponds to A0 on the Sensor Shield V5.0
adc2 = machine.ADC(machine.Pin(2))

adc2.atten(machine.ADC.ATTN_11DB)  # Sets the analog input range

threshold = 32768  # Sets the wet/dry threshold

while True:  # Repeats forever

    water = adc2.read_u16()  # Reads the sensor value

    if water < threshold:  # Checks if water is detected

        start = time.ticks_ms()  # Saves the wet start time

        print('Water detected')  # Reports the wet condition

        while adc2.read_u16() < threshold:  # Waits while it stays wet
            time.sleep(0.1)  # Adds a short pause

        end = time.ticks_ms()  # Saves the dry time

        duration = time.ticks_diff(end, start)  # Calculates wet duration

        print('Water cleared')  # Reports that the sensor is dry

        print('Wet time:', duration, 'ms')  # Shows the wet duration

    time.sleep(0.1)  # Waits before checking again

🎮 Count and Measure Wet Events

Goal Count separate wet events and report the duration of each event to the PC. Concepts Analog Input · Threshold · Counter · Timing · Variables · Serial Output

import machine  # Controls the board hardware
import time     # Controls pauses and timing

# Sets up GPIO2 as an analog input for the rain sensor
# GPIO2 corresponds to A0 on the Sensor Shield V5.0
adc2 = machine.ADC(machine.Pin(2))

adc2.atten(machine.ADC.ATTN_11DB)  # Sets the analog input range

threshold = 32768  # Sets the wet/dry threshold

count = 0  # Stores the number of wet events

while True:  # Repeats forever

    water = adc2.read_u16()  # Reads the sensor value

    if water < threshold:  # Checks if a wet event begins

        count += 1  # Adds one to the event counter

        start = time.ticks_ms()  # Saves the wet start time

        print('Wet event:', count)  # Shows the event number

        print('Water detected')  # Reports the wet condition

        while adc2.read_u16() < threshold:  # Waits while it stays wet
            time.sleep(0.1)  # Adds a short pause

        end = time.ticks_ms()  # Saves the event end time

        duration = time.ticks_diff(end, start)  # Calculates wet duration

        print('Duration:', duration, 'ms')  # Shows the event duration

        print('Water cleared')  # Reports that the sensor is dry

        print('---')  # Separates each event

    time.sleep(0.1)  # Waits before checking again