Project in progress
Simple Arduino Digital Clock Without RTC

Simple Arduino Digital Clock Without RTC © GPL3+

A simple Arduino clock without RTC module for beginners.

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Components and supplies

Necessary tools and machines

09507 01
Soldering iron (generic)
In case you are using the perf board

Apps and online services

Autodesk 123d Circuits
Used to draw the circuit
Ide web
Arduino IDE
To upload code to Arduino

About this project


It's just a simple digital clock controlled by Arduino without using any RTC module (Real Time Clock). Every time you switch on this clock you've to set it to the present time, just like the analog clocks found in homes.

My aim is to give beginners some understanding on how to work with Arduino using only simple materials and without lots of Incomprehensible codes. So let's start.

Let's Start

Anyone with little experience in using a breadboard, connecting wires can make this circuit easily. There is nothing to worry just follow the diagram and connect using male jumper wires or you could use the perfboard and solder everything.

Follow the circuit diagram:

First connect the LCD display, tactile switches, resistors, and potentiometer. Follow the step-by-step diagram given below if you are having trouble connecting the circuit:


Then upload the code given below to your Arduino using Arduino IDE:

Finish the connections with Arduino. And that's it you've built your Arduino digital clock.


Now power up the Arduino either by connecting the USB cable or by using a 12V adapter. Arduino should start and the LCD backlight should glow. Don't worry if you see nothing on the LCD. Try turning the potentiometer, you can see the text becoming clearer. Stop turning when you've achieved your desired contrast. The button on the right is for changing the hour and the one on left is for changing the minute according to the circuit diagram.

One last thing

You can change the message displayed below the time by changing:

lcd.print("HAVE A NICE DAY"); 

Text in the code.

Change HAVE A NICE DAY to something like GOOD MORNING , GOOD EVENING or anything else. Save it and then re-upload it to the Arduino.

Autodesk circuit provides the ability to build and simulate simple circuits, so if you want to build and simulate circuits visit this link.

Furthermore: Designing the clock body

Now that you've built the circuit on a breadboard transfer it to a prefboard so you can house everything inside a box. it wouldn't be that hard to copy everything onto a prefboard. But keep in mind do not solder the pushbuttons on the prefboard itself, using some wire extend the pushbuttons so that we can stick it outside the box

Since we have built the clock mechanism, display and all let's build a body to house all our electronics. I prefer using cardboard for making it because it's much easier to use and best of all it's bio-degradable.

Making the Box

We are going to make a box that houses all our electronics, Arduino, etc. The required dimensions of the box are 8cm (length) x 5cm(breadth) x 4cm(height)

  • Copy the template onto the cardboard either by drawing the diagram onto the cardboard or by printing the (the real box template) template given below on an A4 sheet and then sticking it onto the cardboard.
  • Cut out the template.
  • Cut out the 'x' marked rectangle so that LCD display can be seen.
  • Cut along the red line so that we can fold everything to make a box.
  • Place the electronics inside the box.
  • Fold up everything and stick them using hot glue.
  • Cut holes so that you can take pushbuttons out and stick them on the side of the box and to connect 12 v adapter to power the electronics.

Building the circles

Wondering why I chose this kind of design?

It's because I'm planning to add some more features to this clock and when I finish it, I'll let you guys know.

  • Cut out three circles

One with 75 cm radius, second one with 65cm radius and another one with the 55cm radius as in the template given below

  • Cut out a 7cm x 2cm rectangle exactly at the middle of every circle or you could use printed template pasted on the cardboard to cut it out.
  • Paint the circles with your favorite color and also add your own designs!
  • On top of the big circle stick the medium sized circle aligning the cutout rectangle and then stick the smaller one on top of it in the same fashion

Bringing it all together

Paste the Box containing all the electronics on the back of the big circle aligning the display of the LCD with our cutout rectangle.Stick them all together using hot glue gun. Glue a hook or something like that on the back of the clock so that you can hang it on your wall

  • Power up your Clock
  • Adjust the time using the pushbuttons
  • Hang it on the wall!

And....... that's it!

You have made your very own Arduino Digital Clock


  • Can we modify this project?

With Arduino there is no end, there are many endless ways by which you can modify this project.

For example try to find a way to add an alarm to this clock.

  • Why didn't I use an RTC module ?

For the sake of simplicity I have avoided using RTC module. Most people suggested me to add a RTC module, but for beginners I think this would be enough. If you want to build one there are many projects and tutorials available online.

P.S. For building standalone Arduino so that you can use this clock without the need to include the Arduino permanently, visit these links:

If you have anymore queries, post them below in the comment section. I will try to upload a video on construction in future updates. So see you all with another project.

And thank you for your time.

Custom parts and enclosures

The Real Box Template
template 2
template 3


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