Water level detection using ESP8266 NodeMCU and HC-SR04

ESP8266 24-05-26

13 0

Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- MicroPython code for ESP8266 NodeMCU

Objective of the project

The objective of the water level detection system using ESP8266 NodeMCU, HC-SR04 ultrasonic sensor, and LCD display is to measure and monitor the level of water inside a glass (or container) in real time.

This system is designed to:

- detect the distance between the sensor and the water surface.

- calculate the water level based on this distance.

- display the water level on an LCD screen for easy reading.

- provide a simple and low-cost smart monitoring solution for liquid level measurement.

Functioning of the Project

1- Ultrasonic Measurement (HC-SR04)

The HC-SR04 sensor is placed above the glass. It sends ultrasonic waves toward the water surface and measures the time taken for the echo to return. This time is used to calculate the distance between the sensor and the water surface.

2- Processing (ESP8266 NodeMCU)

The ESP8266 receives the distance data from the sensor. It processes this information and converts it into a water level value based on the height of the glass.

3- Display (LCD Screen)

The calculated water level is shown on the LCD display. It can be displayed as:Water level percentage and graphical bars

4- Working Principle in Real Life

When water is poured into the glass, the distance between the sensor and the water surface decreases. The ESP8266 detects this change and updates the LCD display in real time. When water is removed, the level decreases accordingly.

Required Components

1. ESP826 NodeMCU

The ESP8266 NodeMCU is the main controller of the system. It is a low-cost Wi-Fi microcontroller used to:

- read data from the HC-SR04 sensor

- process the distance values

- calculate the water level

- send results to the LCD display

It acts as the “brain” of the project.

2. HC-SR04 sensor

HC-SR04

The HC-SR04 sensor is used to measure the distance between the sensor and the water surface. It works by transmitting ultrasonic waves and receiving the reflected waves from the water.

3. LCD Display with I2C Module

The LCD I2C display is used to show the water level information in real time. It can display percentage values and graphical bars representing the water level.

4. Jumper Wires

Jumper wires

Jumper wires are used to establish electrical connections between the ESP8266 NodeMCU, the sensor, and the LCD display.

5. Breadboard

The breadboard is used to connect the electronic components without soldering. It simplifies circuit assembly and testing.

Circuit Connections of system

1- Connection of HC-SR04 sensor to ESP8266 NodeMCU

HC-SR04 sensor	ESP8266 NodeMCU
VCC	5V
GND	GND
Trig	D5
Echo	D6

2- Connection of LCD I2C display to ESP8266 NodeMCU

LCD I2C display	ESP8266 NodeMCU
VCC	5V
GND	GND
SDA	D2
SCL	D1

MicroPython code for ESP8266 NodeMCU

This MicroPython program is designed to implement a smart water level monitoring system using an Espressif Systems, an HC-SR04, and an LCD I2C display.

You need to install this two libraries : i2c_lcd et lcd_api for I2C LCD screen.

from machine import Pin, I2C, time_pulse_us
from time import sleep, sleep_us
from i2c_lcd import I2cLcd

# ==============================
# I2C + LCD (ESP8266 NodeMCU)
# SCL = D1 (GPIO5), SDA = D2 (GPIO4)
# ==============================
# Initialize I2C communication for LCD display
i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000)

# Initialize LCD (I2C address = 0x27, size = 2 rows x 16 columns)
lcd = I2cLcd(i2c, 0x27, 2, 16)

# ==============================
# HC-SR04 ULTRASONIC SENSOR
# ==============================
# TRIG sends ultrasonic pulse
TRIG = Pin(14, Pin.OUT)   # D5 (GPIO14)

# ECHO receives reflected pulse
ECHO = Pin(12, Pin.IN)    # D6 (GPIO12)

# Maximum height of the water container (cm)
MAX_HEIGHT = 6.5

# ==============================
# LCD GRAPHIC BAR (CUSTOM CHARACTERS)
# ==============================
# Create 6 levels of bar graph (0 to full block)
bar_chars = [
    bytearray([0,0,0,0,0,0,0,0]),      # empty block
    bytearray([16,16,16,16,16,16,16,16]),
    bytearray([24,24,24,24,24,24,24,24]),
    bytearray([28,28,28,28,28,28,28,28]),
    bytearray([30,30,30,30,30,30,30,30]),
    bytearray([31,31,31,31,31,31,31,31]) # full block
]

# Load custom characters into LCD memory
for i in range(6):
    lcd.custom_char(i, bar_chars[i])

# Display static title on first row
lcd.move_to(0, 0)
lcd.putstr("Niveau d'eau  ")

# ==============================
# FUNCTION: MEASURE DISTANCE
# ==============================
def measure_distance():
    # Send ultrasonic trigger pulse
    TRIG.off()
    sleep_us(2)
    TRIG.on()
    sleep_us(10)
    TRIG.off()

    # Measure echo pulse duration (timeout = 30ms)
    duration = time_pulse_us(ECHO, 1, 30000)

    # If no signal is received, return 0
    if duration < 0:
        return 0

    # Convert time to distance (cm)
    distance = (duration * 0.034) / 2
    return distance

# ==============================
# FUNCTION: MAP VALUE RANGE
# ==============================
# Converts a value from one range to another
def map_value(x, in_min, in_max, out_min, out_max):
    return int((x - in_min) * (out_max - out_min) /
               (in_max - in_min) + out_min)

# ==============================
# MAIN LOOP
# ==============================
while True:

    # Measure distance from sensor to water surface
    distance = measure_distance()

    # Calculate water level based on container height
    water_level = MAX_HEIGHT - (distance - 2.3)

    # Limit water level between 0 and max height
    if water_level < 0:
        water_level = 0
    if water_level > MAX_HEIGHT:
        water_level = MAX_HEIGHT

    # Convert water level to percentage
    percent = int((water_level / MAX_HEIGHT) * 100)

    # Display percentage on LCD (second row)
    lcd.move_to(0, 1)
    lcd.putstr(str(percent) + "%   ")

    # Define number of bar segments
    total_bars = 10

    # Convert percentage into 0–50 scale (5 levels per bar)
    filled = map_value(percent, 0, 100, 0, total_bars * 5)

    # Start position of bar graph on LCD
    lcd.move_to(5, 1)

    # Draw bar graph on LCD
    for i in range(total_bars):
        bar_level = filled - (i * 5)

        if bar_level >= 5:
            lcd.putchar(chr(5))   # full block
        elif bar_level > 0:
            lcd.putchar(chr(bar_level))  # partial block
        else:
            lcd.putchar(chr(0))   # empty block

    # Small delay before next measurement
    sleep(0.5)

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from machine import Pin, I2C, time_pulse_us

from time import sleep, sleep_us

from i2c_lcd import I2cLcd

# ==============================

# I2C + LCD (ESP8266 NodeMCU)

# SCL = D1 (GPIO5), SDA = D2 (GPIO4)

# ==============================

# Initialize I2C communication for LCD display

i2c = I2C(scl=Pin(5), sda=Pin(4), freq=100000)

# Initialize LCD (I2C address = 0x27, size = 2 rows x 16 columns)

lcd = I2cLcd(i2c, 0x27, 2, 16)

# ==============================

# HC-SR04 ULTRASONIC SENSOR

# ==============================

# TRIG sends ultrasonic pulse

TRIG = Pin(14, Pin.OUT) # D5 (GPIO14)

# ECHO receives reflected pulse

ECHO = Pin(12, Pin.IN) # D6 (GPIO12)

# Maximum height of the water container (cm)

MAX_HEIGHT = 6.5

# ==============================

# LCD GRAPHIC BAR (CUSTOM CHARACTERS)

# ==============================

# Create 6 levels of bar graph (0 to full block)

bar_chars = [

bytearray([0,0,0,0,0,0,0,0]), # empty block

bytearray([16,16,16,16,16,16,16,16]),

bytearray([24,24,24,24,24,24,24,24]),

bytearray([28,28,28,28,28,28,28,28]),

bytearray([30,30,30,30,30,30,30,30]),

bytearray([31,31,31,31,31,31,31,31]) # full block

]

# Load custom characters into LCD memory

for i in range(6):

lcd.custom_char(i, bar_chars[i])

# Display static title on first row

lcd.move_to(0, 0)

lcd.putstr("Niveau d'eau ")

# ==============================

# FUNCTION: MEASURE DISTANCE

# ==============================

def measure_distance():

# Send ultrasonic trigger pulse

TRIG.off()

sleep_us(2)

TRIG.on()

sleep_us(10)

TRIG.off()

# Measure echo pulse duration (timeout = 30ms)

duration = time_pulse_us(ECHO, 1, 30000)

# If no signal is received, return 0

if duration < 0:

return 0

# Convert time to distance (cm)

distance = (duration * 0.034) / 2

return distance

# ==============================

# FUNCTION: MAP VALUE RANGE

# ==============================

# Converts a value from one range to another

def map_value(x, in_min, in_max, out_min, out_max):

return int((x - in_min) * (out_max - out_min) /

(in_max - in_min) + out_min)

# ==============================

# MAIN LOOP

# ==============================

while True:

# Measure distance from sensor to water surface

distance = measure_distance()

# Calculate water level based on container height

water_level = MAX_HEIGHT - (distance - 2.3)

# Limit water level between 0 and max height

if water_level < 0:

water_level = 0

if water_level > MAX_HEIGHT:

water_level = MAX_HEIGHT

# Convert water level to percentage

percent = int((water_level / MAX_HEIGHT) * 100)

# Display percentage on LCD (second row)

lcd.move_to(0, 1)

lcd.putstr(str(percent) + "% ")

# Define number of bar segments

total_bars = 10

# Convert percentage into 0–50 scale (5 levels per bar)

filled = map_value(percent, 0, 100, 0, total_bars * 5)

# Start position of bar graph on LCD

lcd.move_to(5, 1)

# Draw bar graph on LCD

for i in range(total_bars):

bar_level = filled - (i * 5)

if bar_level >= 5:

lcd.putchar(chr(5)) # full block

elif bar_level > 0:

lcd.putchar(chr(bar_level)) # partial block

else:

lcd.putchar(chr(0)) # empty block

# Small delay before next measurement

sleep(0.5)

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Water level detection using ESP8266 NodeMCU and HC-SR04

Tutorial plan

1- Objective of the project

2- Required Components

3- Circuit Connections of system

4- MicroPython code for ESP8266 NodeMCU

Objective of the project

Functioning of the Project

Required Components

Circuit Connections of system

MicroPython code for ESP8266 NodeMCU

0 comment

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