Published September 15, 2019 © GPL3+

Ebb and Flow Hydroponic Mini System

Grow your own lettuce, greens, and strawberries with a soil-less system that will give them just the right amount of nutrient rich water.

BeginnerFull instructions provided3 hours3,462

Things used in this project

Hardware components

ELEGOO UNO R3 Board ATmega328P ATMEGA16U2 with USB Cable

ELEGOO 3PCS 400 tie-points breadboard, 4 power rails for Arduino Jumper Wire

Elegoo Breadboard Jumper Wires - Ribbon Cables Kit

16 x 2 LCD with Backpack

5V 2 channel relay

DC Micro Submersable Pump

water sensor

DC Power Supply

1/4 inch Vinyl Tubing

2 inch Net Pots

Rockwool Hydroponic Plugs

6 Quart Storage Bins

Hydroponic Clay Pebbles

Software apps and online services

Arduino IDE

Hand tools and fabrication machines

Awl

Retractable Utility Knife

Wire Stripper & Cutter, 18-10 AWG / 0.75-4mm² Capacity Wires

Story

This Mini Ebb and Flow Planter can support small plants such as lettuce. Use mineral rich water with a pH around 6.5.

Step 1. Cut holes in the lids of your containers and the bottom of you top container (I find it easier and safer to use the awl to punch holes where I will need to cut and then the utility knife to finish the job):

Lid for the top container should have 4 - 2" round holes, 1 - 3/8 " round hole and 1 - 1" slit.

1 / 3 • Use awl to poke holes along the lines and then carefully poke through with the utility knife.

Lid for the bottom container should have 1 - 4" round hole in the center, 1 - 3/8" round hole, and 1 small hole to fit the wiring for the pump.

1 / 2 • 4 inch center hole allows water from top container flow through to the bottom container.

Poke 8 or 9 small holes into the center-bottom of the top container.

I'm using the bottom container's lid to gauge where I poke the holes in the bottom of the top container.

Step 2. Assemble the pieces

The pump goes in the bottom container. The vinyl tube comes out of the bottom container and into the top container through the 3/4" holes. The pump wiring comes out through the smaller hole.
The water sensor is slipped through the slit in the top lid. I use hot glue to help secure it into place.
The 2" net pots fit into the 4 holes in the top lid. Plants that have been started in the rockwool plugs go into those pots with a few hydroponic clay pebbles.

Step 3. Follow the schematic to wire your electrical components together.

Cut the end of the power supply off. You will need to use the wire stripper to expose the wire in order to connect it to the pump and relay. I connected the exposed wires for the pump and power source to male-to-male wires before connecting them to the relay. It would probably be better to solder them together, but I just wrapped the wires together and then hot glued them... Worked for me.

Code

Mini Ebb and Flow

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // 

int pump = 11; // pin that turns on the water pump
int sensorValue = 0; //value from water level sensor
const int analogInPin = A0; //pin that reads water level sensor
const int LCD = A5; 

void setup()
{
  lcd.init();//initialize the LCD
  lcd.init();//print a message to the LCD
  lcd.backlight();
  lcd.setCursor(2,0);
  lcd.print("Ebb and Flow");
  pinMode(pump, OUTPUT); // set pin 11 to an output so we can use it to turn on the pump 
  Serial.begin(9600); // set up communication back to serial monitor  lcd.init():
 
 
}

void loop()
{
  sensorValue = analogRead(analogInPin); // the value from water level sensor
  Serial.print("Sensor = "); // print on serial monitor
  Serial.println(sensorValue); // printing the value on serial monitor
  
  if(sensorValue <=60) // If below _ then turn pump, LED, and LCD on
  {
    Serial.println("pump should be running");
    digitalWrite(pump, LOW); // turn on the motor
    delay(2000);
    lcd.setCursor(4,1);
    lcd.print("Pump On");
   }

  if(sensorValue >=100) // If above _ then turn pump, LED, and LCD off
  {
    Serial.println("pump should be off"); //print on serial monitor
    digitalWrite(pump, HIGH);  // turn off the motor
    lcd.setCursor(4,1);
      lcd.print("Pump Off");
    delay(2400000); //wait 40 minutes
  }
  delay(5000);        // check sensor every 5 seconds
}