Introduction: Aquarium Auto Lighting System

About: Hello , my name is John Vasilakis and this is my Arduino profile ! Visit my site

In this DIY guide I will show you how to make your own Arduino aquarium auto lighting system. In this project I decided to make my own PCB that is based on Arduino UNO microcontroller - Atmega328p. Bellow you will find the electronic schematic with PCB layout so you can easily produce it.

The current time can be set for the first time (or when the coin battery is low) via the serial monitor. You can change the lighting change time or led color from code.

~Project updates can be found here:

~Watch the video below:

Step 1: What You Will Need - Hardware

Step 2: Circuit Schematic and PCB

Enter here to see and make any changes to the above circuit.

Step 3: The Code

Connect your circuit with TTL to USB module with 5 cables to the programming header. The pins RX and TX must be cross-connected.

NOTE: If you are using the Arduino UNO board make sure to remove the ATmega328 IC from it first and connect the headers RX to RX and TX to TX pins of the board. The RS pin must be connected to Arduino UNO reset pin.

/*  Arduino based - Aquarium Auto Lighing System
* More info can be found at:
* Dev:Michalis Vasilakis Date:21/2/2018 Var:1.0

//Libraries (many thanks to Developers)
#include <Adafruit_NeoPixel.h>
#include <RTClib.h>

const int DIN = 2; //Neopixel DIN pin to Arduino Pin 2
const int PIXELS = 29; //How many neopixel leds do you have?
RTC_DS1307 rtc; //Create an object for DS1307 I2C library
Adafruit_NeoPixel pixels = Adafruit_NeoPixel(PIXELS, DIN, NEO_GRB + NEO_KHZ800); //Create an object for NeoPixel library

int H,M; //H for hour and M for minutes
String Time; // Use readTime(); Serial.print(Time); for printing the time in serial monitor
//Variables For color setting
boolean newColor = false;
int r=0;
int g=0;
int b=0;
//Following variables are used for the time setting from serial monitor
boolean newMessage = false;
boolean messageCompleted = false;
char incomingByte;
String command;
//Delay without delay() for fade
unsigned long previousMillis = 0;
const long interval = 250; //Change this value (ms)

void setup() {
pixels.begin(); //Initialize the NeoPixel library
rtc.begin(); //Initialize the RTC DS1307 library
//This will run only if the rtc battery is low or rtc ic has wrong time set
if (! rtc.isrunning()) {
Serial.println("RTC is NOT running!");
// This line sets the RTC with an explicit date & time, for example to set
// January 1, 2018 at 00:00am you would call:
rtc.adjust(DateTime(2018, 01, 01, 00, 00, 0));
Serial.println("Aquarium Auto Lighting System");
Serial.println("Visit the for more info \n");
Serial.println("- To set the time send '<SHH:MM>' (example: <S14:05>)");

void loop() {
setTime(); //Check for serial set command

//Change time and color values bellow if you want
//From 00:00 to 07:00
if (H>=0 && H <7) {
//From 07:00 to 12:00
else if (H>=7 && H<12){
else if( H>=12 && H<19){
else if (H>=19 && H<21){
//Send color to led strip
void setColor(int R,int G,int B){
while ((r!=R) || (g!=G) || (b!=B)){
setTime(); //Check for serial set command

unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval) {
previousMillis = currentMillis;
for(int i=0;i<PIXELS;i++){
// pixels.Color takes RGB values, from 0,0,0 up to 255,255,255
pixels.setPixelColor(i, pixels.Color(r,g,b));;
if (r!=R && r<R){
else if (r!=R && r>R){
if (g!=G && g<G){
else if (g!=G && g>G){
if (b!=B && b<B){
else if (b!=B && b>B){

//Read time from RTC
void readTime(){
DateTime now =;
H = now.hour();
M = now.minute();
Time = "Current time in RTC: " + String(H) + ":" + String(M);

//Set time, send <SHH:MM> (example <S05:00>)
void setTime(){
if (Serial.available()){
incomingByte =;
else if (incomingByte=='<'){
if (newMessage){
//Set time
if (command.charAt(1)=='S'){
int h = (command.substring(2,4)).toInt();
int m = (command.substring(5,7)).toInt();

Step 4: 3D Parts

Step 5: Well Done!

I hope you liked this, let me know in the comments!!!

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Participated in the
Indoor Lighting Contest