Introduction: Bluetooth LED Alarm Clock (7-Segment Display From Trash)

Hello everyone. Welcome back to another instructable.

Last time I have posted an Instructable on how to turn trash into 4-Digit 7-Segment Display

Today I am going to make a simple alarm clock with the display.

Time can be set via android app using bluetooth .

Step 1: Gather the Parts

Here are the parts which you need to make this clock:

The display ( )

(Or you can create one from 7-segment displays)

Arduino UNO (Or nano, it can be made permanent and takes less space)

HC-05 bluetooth module


1k x3

10k x1

push button

Piezo Buzzer (you can use anything musical for alarm, eg:- greeting card circuit,etc)

9v battery

usb cable and computer for programming

An Android device with bluetooth.

Step 2: The Circuit

The circuit is very simple.

Connect all the parts as shown in above diagram.

The free ends of wire has been marked with the connections of the display.

Step 3: The Code

The code is written using Arduino IDE.

Download the zip , extract, and upload.

The Android app is made using AppInventor2

Install in in the phone.

The .aia file is the source code for the android app.

Watch this video.

Step 4: Final Thoughts

This clock does not uses RTC module.

But it is easy to set the time using bluetooth.

Just set the time and disconnect the device.

Time can be also set using computer. But you need to make the software for the computer or use the serial monitor.

If you have any Doubts leave a comment

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