Picture of Smallest Binary Clock
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.

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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

Picture of Programming and Wireing
binary clock.jpg
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

Picture of 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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gip_mad5 years ago
I'm sorry, but it's not the smallest.. Mine is smaller!! ;D<br /><a href=""></a>
macobt (author)  gip_mad5 years ago
Sorry I found the code but,can you have it  in hex?And what number is the chip?
gip_mad macobt5 years ago
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
macobt (author)  gip_mad5 years ago
This is good watch,Bravo.Can you post me the schematic and code for this project.
Regards macobt
techno guy1 year ago
how do you cut the tops off the LEDs

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

lburns41 year ago
About how much does it cost to make?

costs about 4$ for me

My final version with cr2032 can run 3 days with full accuracy,(after that it looses accuracy)
macobt (author)  Suraj Grewal1 year ago
Very good job suraj.
mrmerino2 years ago
If I want to use a crystal with a different value, could I change something in the code to accommodate?
macobt (author)  mrmerino1 year ago
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
vanwazltoff2 years ago
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

Late reply, I know, but did you fix the problem? What was wrong?
i've tried it third time
but the same chip i reprogrammed to make macobt's other clock
ill make a video on it also onse i make it compact
its a single digit numeric clock
macobt (author)  Suraj Grewal2 years ago
First you will need to use new pic,because if the pic get hot that mean that the pic is dead :( As you can see the circuit is very simple,check your programmer its ok.
Or send me some pictures to
mmenendez2 years ago
hey do i need to program it, i think i do so with which am i suppose to program is it Arduino Uno? thanks also is there a way to make it without programming? thanks
macobt (author)  mmenendez2 years ago
This is PIC microcontroller,its not arduino.
this worked for me
This is not an Arduino chip, it is a PIC. There are many different programmable microcontrollers around, Arduino just happens to be the easiest for beginners.
Silentz4 years ago
Hi, just wondering what battery you'd need to use to run this? Thanks
Silentz Silentz4 years ago
Also, would this work with any 18 pin PIC chip?
c1c2c3 Silentz2 years ago
macobt (author)  Silentz4 years ago
This clock works with PIC16F84 microcontroller,and voltage is 5 volts.
How should I download the program on the micro-controller? Do I need to connect it to a breadboard or something?
(removed by author or community request)
macobt (author)  DELETED_awesome7462 years ago
First you press ''set'' button than with ''select'' button you set the numbers,remember that the clock is set in opposite way I mean first you set the last number,minutes than hours.
mg99903 years ago
could you maybe help me? im trying to make a clock very similar to this accept the led changes every hour and it shows 12 leds (one for each hour) Could i do this in a similar way to yours?
16zzundel53 years ago
Here are pictures of my board design and Eagle schematic. If anyone would like these files, please email me. I just placed an order with BatchPCB and Futurlec for the board and components, respectively. I am very excited for this project! If anyone would like me to program their PIC, I can do that.
macobt (author)  16zzundel53 years ago
great job,just keep going with good work.
I can't get your hex code to download. It says it is an incorrect link.
macobt (author)  16zzundel53 years ago
Here is new link
mwagner633 years ago
What programmer should i use for this that is not a jdm programmer
techno guy3 years ago
You should put this on top of a wrist band and you can make a wrist watch like that.
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