Smallest Binary Clock





Introduction: Smallest Binary Clock

About: My name is marjancho and I love electronics,makeing gadgets,hack and pranks.

This is the Smallest Binary Clock that show the time with just 4 leds.
The brain in this clock is PIC16F84A,The time will be displayed when the 'show' pushbutton is pressed. The digits of the time are displayed in BCD on the four LEDs. Tens of hours is displayed followed by hours, tens of minutes and then minutes.

Step 1: Parts

For this project you will need:

2.Crystal 32.768khz(you may find in ordinary clocks)
3.Four leds any color
4. Resistors 4x270 ohm
5. Ceramic cap 2x33 Pf
6. Push Buttons 3 peaces

Step 2: Programming and Wireing

First you must program the chip,I use the software ICprog and here is hex code: SmallestBc.
The schematic and wiring you can see here  they are very simple to understand.

Step 3: Finish Clock

Here is my 4 leds binary clock,is too fun to have it,I love this clock you may make too be clock watch.
Also I have upload a gif image too see how can you make too look the clock.
Here is my links:



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Please be positive and constructive.




I can't download the code.. could someone please reupload it ??

I'm sorry, but it's not the smallest.. Mine is smaller!! ;D<br /><a href=""></a>

5 replies

Sorry I found the code but,can you have it  in hex?And what number is the chip?

Schematics and code are on my website, but since it's a very old project I don't actually remember the chip name and I don't know where to find the hex... Sorry! :(

isn't it same sized as this -

accept the one in link is not on pcb,otherwise its same sized

sorry to say but ^macobt's^ one is smaller it appears bigger in photo, his one can be made as small as the chip itself using smd leds

This is good watch,Bravo.Can you post me the schematic and code for this project.
Regards macobt

Recently I bought blue 5mm(and only blue leds were available) leds with flat tops

My final version with cr2032 can run 3 days with full accuracy,(after that it looses accuracy)

1 reply

Very good job suraj.

If I want to use a crystal with a different value, could I change something in the code to accommodate?

2 replies

No you cant use difrent crystal,the time will speed up or speed down

Okay, so I can't just tell the code to act differently?

I made one too-

last time i burnt the crystal this time all went ok


have you tried surface mount resisters? it would give a much cleaner look

I tryed this,pic written properly and confermed data,
but when connected to circuit given by you, ic gets hot and gets destroyed even at 3volts
but i liked your idea and will try to troubleshoot.
this thing made me crazy and even I dont know from where i got to arrange the 3 pics
ive got i just got them arranged some how.
I really want to make this thing

1 reply

Late reply, I know, but did you fix the problem? What was wrong?