Countertop water filtration device

Our design is a countertop water filtration unit specifically designed for efficient manganese removal from tap water. It integrates a built-in flow sensor that tracks water usage to inform users when the filter needs replacement, which typically occurs after six months of use. The system prioritizes ease of installation and everyday usability, with a compact footprint suitable for residential kitchens. A digital interface provides real time data to enhance user interaction. The design includes a modular filter cartridge and an accessible housing unit, enabling quick maintenance and replacement without tools.

Families in Hudson’s Hope (BC) urgently need an accessible and effective household water filtration system to remove manganese contamination from their water supply. With the municipal plant unable to address this issue and no immediate town-wide solution, a reliable, low-cost, and easy-to-maintain filtration option is necessary to ensure safe drinking water for daily use.

The schematic diagram provides a simplified, high-level representation of the 20-POTABLE system and the flow of water through each stage. Unfiltered water from the tap enters the system and passes through a 5-stage filtration unit, where manganese and other impurities are removed. The filtered water is then directed into a funnel to control the flow into the measurement system. Next, water passes through a flow meter (water sensor), which sends real-time usage data to an Arduino microcontroller (not shown here for clarity). This information is used to determine when the filter needs replacing. Finally, the clean, filtered water is collected in a reservoir for user access. This schematic captures the core components and logical flow of the system while minimizing unnecessary detail, making it ideal for quickly communicating the design concept and identifying integration or risk points.

The layout drawing provides an exploded view of the filtration system, illustrating the spatial arrangement and assembly of all major components. From top to bottom, the system includes a removable cap, the main filtration cartridge, the base housing, and the electronics module. The electronic components — including the LCD display, Arduino board, and power module — are housed in the lower section, with designated cutouts and mounts for each part. The LCD display is externally visible to provide user feedback, while the Arduino controls the LED indicator and monitors flow data from the sensor. This drawing communicates how each part is assembled, highlighting clear interfaces between components and allowing for easy identification of potential integration challenges or maintenance considerations. The modular nature of the design supports straightforward assembly and part replacement.

The process diagram illustrates the complete flow of water through the 20-POTABLE filtration system, highlighting how each stage contributes to the filtration and monitoring process. The process begins with water entering the system from the top, where it flows through a filtration unit designed to remove manganese and other impurities. Once filtered, the water falls into a funnel, which directs the flow towards a built-in flow sensor. The flow sensor measures the volume of water passing through the system and sends data to an Arduino microcontroller for processing. The Arduino continuously monitors water usage and determines whether the filter’s lifespan has been exceeded. If so, it keeps an LED on as an indicator and displays a message on the LCD screen instructing the user to change the filter. After passing through the flow sensor, the filtered water exits the system through the bottom and collects in a reservoir, completing the process. The diagram effectively demonstrates the logical flow of the filtration process, the role of each component, and the decision-making point where the Arduino triggers notifications based on water usage data.

Here are all the detail drawings that we made during this project.

Here is the assembly drawing for this project.

Here is all of the code that went into this project as well as comments:

# include <LiquidCrystal_I2C.h>
# define led A1 // Single yellow LED
# define button 12 // Button connected to terminal 1b

volatile int flow_frequency; // Measures flow sensor pulses
float vol = 0.0, l_minute;
unsigned char flowsensor = 2; // Sensor Input
float flowRate;
unsigned long currentTime;
unsigned long cloopTime;
unsigned long lastFlashTime = 0; // Track last LED flash time
const float MAX_VOLUME = 1200.0; // Max limit before filter replacement
LiquidCrystal_I2C lcd(0x27, 16, 2);
void flow() {
 flow_frequency++;
} // Interrupt function for flow sensor
void setup() {
 pinMode(flowsensor, INPUT);
 pinMode(buzzer, OUTPUT);
 pinMode(button, INPUT_PULLUP); // Button input with internal pull-up
 digitalWrite(flowsensor, HIGH); // Optional Internal Pull-Up
 Serial.begin(9600);
 digitalWrite(led, HIGH); // LED always ON to indicate machine is working
 attachInterrupt(digitalPinToInterrupt(flowsensor), flow, RISING); // Setup Interrupt
 lcd.init();
 lcd.backlight();
 lcd.setCursor(3, 0);
 lcd.print("WELCOME TO");
 lcd.setCursor(3, 1);
 lcd.print("20-POTABLE!");
 delay(3000);
 lcd.clear();
}
void loop() {
 checkFlowRate();
 checkButton();
 checkFlashingLED();
}
void checkFlowRate() {
 currentTime = millis();
 if (currentTime >= (cloopTime + 1000)) {
 	 cloopTime = currentTime; // Updates cloopTime
 	 if (flow_frequency != 0) {
 		 l_minute = (flow_frequency / 7.5) / 60.0; // L/min to L/sec
 		 flowRate = l_minute * 1000; // Flow rate in mL/sec
 		 vol += l_minute; // Accumulate volume in L
 		 lcd.clear();
 		 lcd.setCursor(0, 0);
 		 lcd.print("Flow:");
 		 lcd.print(flowRate);
 		 lcd.print(" mL/S");
 		 lcd.setCursor(0, 1);
 		 lcd.print("Used: ");
 		 lcd.print(vol);
 		 lcd.print("/1200L");
 		 flow_frequency = 0; // Reset Counter
 		 Serial.print("Current flow rate: ");
 		 Serial.println(flowRate);
 		 Serial.print("Total volume: ");
 		 Serial.println(vol);
 		 // Check if flow volume exceeds the limit
 		 if (vol >= MAX_VOLUME) {
 			 alertUser();
 		 }
 	 }
 }
}
void alertUser() {
 lcd.clear();
 lcd.setCursor(0, 0);
 lcd.print("Replace Filter!");
}
void checkFlashingLED() {
 if (vol >= MAX_VOLUME) {
 	 if (millis() - lastFlashTime >= 30000) { // Flash LED every 30 seconds
 		 digitalWrite(led, LOW);
 		 delay(500);
 		 digitalWrite(led, HIGH);
 		 lastFlashTime = millis();
 	 }
 }
}
void checkButton() {
 if (digitalRead(button) == LOW) {
 	 Serial.println("Button Pressed! Timer is reset");
 	 lcd.clear();
 	 lcd.setCursor(1, 0);
 	 lcd.print("Timer is reset!");
 	 vol = 0.0; // Reset volume counter
 	 lastFlashTime = millis(); // Prevent immediate flashing after reset
 	 delay(1000); // Debounce delay
 	 lcd.clear();
 }
}

• Purpose: The purpose of this test was to measure the filtration system’s effectiveness in reducing manganese levels in water. Manganese water was achieved by placing manganese pills into pure water and running it through the filter to test it.
• Description: Water samples were taken before and after filtration to measure several key parameters, including conductivity, pH, nitrate concentration, chlorine levels, and turbidity.

• Conductivity increased significantly, indicating ion exchange or mineral leaching from the filter.
• pH improved from slightly acidic (~6) to more neutral (~7.8), showing effective filtration. Mineral stones increased water pH, helping prepare the water for manganese removal.
• Nitrate removal was highly effective, reducing from 10 mg/L to 0 mg/L.
• Turbidity increased, possibly due to fine particulate matter from the filter media being released into the water. Further backwashing or pre-filtration may help resolve this issue.

Purpose: To analyze the filter’s effectiveness in purifying natural river water by reducing contaminants and improving water quality.

Description: A sample of untreated river water was tested before and after filtration for key parameters such as conductivity, pH, nitrate levels, chlorine levels, and turbidity.

• Conductivity decreased, indicating partial removal of dissolved solids and contaminants.
• pH increased slightly, likely due to minerals introduced during filtration.
• Nitrate removal was successful, reducing from 10 mg/L to 0 mg/L.
• Turbidity decreased significantly, showing effective removal of suspended particles.

Purpose: To assess how the cotton cloth layer at the beginning of the filtration system affects the water flow rate.

Description: Two sets of flow rate measurements were taken: one with the cotton cloth and one without. These flow rates were measured using a flow rate sensor, and muddy water was used for testing.

• The data indicates a generally consistent flow, which is faster than the constraints.
• The cloth significantly slowed down the flow rate, suggesting it captured larger particles in the water. Although it seems less efficient, this is because it filtered a smaller volume.
• Removing the cloth increased the flow rate but might have allowed more particulates to pass through.

Purpose: Test to ensure the filter fits the standard dimensions of a countertop filter.

Description of Test: Three different people measured the filter dimensions using a measuring tape to ensure the design meets the objective of minimizing dimensions.

• The filter fits the standard measurements: Width (10–15 cm), Height (25–33 cm), Depth (13–18 cm).
• Measurements were slightly inconsistent due to being conducted by three different individuals.

Purpose: Test to ensure the filter is easy to assemble.

Description of Test: Three individuals assembled the filter and attached it to the faucet using the provided instruction manual. The assembly process was timed, with an expected duration of under 5 minutes.

• The instruction manual effectively simplified the assembly process.
• All assembly times were under the 5-minute target, confirming ease of setup.

1. Insert Filter Cartridge:

• Place the purchased filter cartridge into the cylindrical compartment of the housing, ensuring a secure and leak-proof fit.

2. Secure the Lid:

• Screw on the stainless-steel lid until fully tightened to prevent leakage and maintain system pressure.

3. Attach Faucet:

• Connect the faucet to the inlet on top of the lid using a standard threaded adapter or fitting as specified in the BOM.

4. Connect Power:  

• Plug the system into a standard wall outlet. The Arduino will automatically boot up and initialize the LCD and monitoring system.

1. Startup Test:

• After powering on, confirm the LCD screen lights up and displays system information.
• Ensure the LED indicator is functioning properly.

2. Water Flow Test:

• Turn on the faucet to allow water to flow through the system.
• Observe for leaks around all fittings, the lid, and the filter compartment.
• Confirm the flow sensor is detecting water movement and sending data to the Arduino.

3. Filter Life Monitoring Test:

• Simulate extended use (manually or with test flow) to verify the LCD prompts a filter replacement after the preset usage threshold (based on volume or estimated 6-month usage).

4. Functionality Validation:

• Ensure filtered water is successfully collected in the reservoir.
• Confirm the LCD and LED indicators update accurately based on flow and filter condition.