Water level monitoring and control in water tank

Introduction

A water level monitoring system uses an ultrasonic sensor to measure the distance to the water surface in a tank. The VSD Squadron Mini Developement Board processes this data to determine the water level. If the level drops below a certain threshold, the system can activate a servo motor to refill the tank. It alerts users with an LED or buzzer when the water level is low, ensuring efficient water management.

Components Required

-VSD Squadron Mini developement board -Servo motor -HC-SR04 Ultrasonic Sensor -External Power Supply -Bread Board -Jumper Wires

Circuit Connection Diagram

Table for Pin connection

HC-SR04 Ultrasonic Sensor	VSD Squadron Mini
Trigger pin	PD4
Echo pin	PD3
VCC	3.3V
GND	GND

Servo Motor	VSD Squadron Mini
Control pin	PD2
OUT1	VCC
OUT2	GND

BULB	VSD Squadron Mini
OUT1	PD6
OUT2	GND

code

#include <ch32v00x.h>
#include <debug.h>

/* PWM Output Mode Definition */
#define PWM_MODE1 0
#define PWM_MODE2 1
/* PWM Output Mode Selection */
#define PWM_MODE PWM_MODE2

/* Threshold distance in cm for water level */
#define WATER_LEVEL_THRESHOLD 10

/* Function to initialize PWM on Timer 1 for the servo motor */
void TIM1_PWMOut_Init(uint16_t arr, uint16_t psc, uint16_t ccp)
{
    GPIO_InitTypeDef GPIO_InitStructure = {0};
    TIM_OCInitTypeDef TIM_OCInitStructure = {0};
    TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure = {0};

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; // Alternate Function Push-Pull
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
    TIM_TimeBaseInitStructure.TIM_Period = arr;
    TIM_TimeBaseInitStructure.TIM_Prescaler = psc;
    TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM1, &TIM_TimeBaseInitStructure);

#if (PWM_MODE == PWM_MODE1)
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
#elif (PWM_MODE == PWM_MODE2)
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2;
#endif
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = ccp;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    TIM_OC1Init(TIM1, &TIM_OCInitStructure);
    TIM_CtrlPWMOutputs(TIM1, ENABLE);
    TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Disable);
    TIM_ARRPreloadConfig(TIM1, ENABLE);
    TIM_Cmd(TIM1, ENABLE);
}

/* Function to configure GPIO Pins */
void GPIO_Config(void)
{
    GPIO_InitTypeDef GPIO_InitStructure = {0};

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);

    // Pin 3: Input for Ultrasonic sensor echo
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; // Input with Pull-Up
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    // Pin 4: Output for Ultrasonic sensor trigger
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // Output Push-Pull
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    // Pin 6: LED indicator
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // Output Push-Pull
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOD, &GPIO_InitStructure);
}

/* Function to trigger the ultrasonic sensor and read the echo duration */
uint32_t Ultrasonic_Read(void)
{
    uint32_t echoTime = 0;

    GPIO_WriteBit(GPIOD, GPIO_Pin_4, SET); // Setting Trigger Pin to send pulses
    Delay_Us(10); // Pulse Width
    GPIO_WriteBit(GPIOD, GPIO_Pin_4, RESET); // Resetting Trigger Pin

    while (GPIO_ReadInputDataBit(GPIOD, GPIO_Pin_3) == Bit_RESET); // Wait for Echo to go high
    while (GPIO_ReadInputDataBit(GPIOD, GPIO_Pin_3) == Bit_SET) echoTime++; // Measure the time Echo is high

    return echoTime;
}

/* Function to calculate distance from echo time */
float Calculate_Distance(uint32_t echoTime)
{
    // Speed of sound in air is 340 m/s or 0.034 cm/us
    // Distance is (time / 2) * speed_of_sound
    return (echoTime / 2.0) * 0.034;
}

/* Function to control LED blinking */
void Blink_LED(uint8_t times, uint16_t on_time, uint16_t off_time)
{
    for (uint8_t i = 0; i < times; i++)
    {
        GPIO_WriteBit(GPIOD, GPIO_Pin_6, Bit_SET); // Turn LED on
        Delay_Ms(on_time); // Delay for on_time

        GPIO_WriteBit(GPIOD, GPIO_Pin_6, Bit_RESET); // Turn LED off
        Delay_Ms(off_time); // Delay for off_time
    }
}

/* Main function */
int main(void)
{
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
    SystemCoreClockUpdate();
    Delay_Init();
    GPIO_Config();
    USART_Printf_Init(115200); // Initialize debug USART

    while (1)
    {
        uint32_t echoTime = Ultrasonic_Read();
        float distance = Calculate_Distance(echoTime);

        printf("Distance: %.2f cm\n", distance); // Print the distance

        if (distance < WATER_LEVEL_THRESHOLD) // If water level is below the threshold
        {
            Blink_LED(3, 200, 100); // Blink LED three times with specified on and off times
            TIM1_PWMOut_Init(100, 480 - 1, 95); // Set PWM to 95% duty cycle to activate the servo motor
        }
        else
        {
            GPIO_WriteBit(GPIOD, GPIO_Pin_6, Bit_RESET); // Turn off LED
            TIM1_PWMOut_Init(100, 480 - 1, 10 ); // Set PWM to 10% duty cycle to deactivate the servo motor
        }

        Delay_Ms(1000); // Wait for 1 second before next reading
    }
}

video

https://github.com/kaushik-97/Tandav_VSD_IIITB-Ethical-RISC-V-IoT-Hackathon

Water level monitoring and control in water tank