Yes, I know, there are already lots and lots of instructables about binary clocks.  I wanted to build one for a long time now so with the USB contest in mind, I gave it a go. So if you like this Instructable then please vote for it in the contest.

As the title suggests, the clock is powered via a usb cable. When you disconnect the clock or turn off the computer, it will keep going on its battery but it won´t show the time until you reconnect it or switch you PC on again.

For this project, I made my own PCB´s. I have only made 3 PCB´s yet and all in the last 14 days so I am really proud oft them. Any suggestions about those are very welcome!

A small video (the flickering of the LEDS in due to the camera).

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Step 1: What do you need:

  • 20 x  LEDS: Any color you fancy
  • 2 x pushbuttons
  • 6 x 100Ohm resistors
  • 2 x 1.5K resistors
  • 2 x 4.7K resistors
  • an Atmega 8
  • a DS1307 real time clock IC
  • a crystal 32.768K
  • a USB connector
  • A 3V battery + holder ( I used a CR2032)
  • a 13pin male header (L-shaped)
  • Soldering Iron and solder
Please be careful when soldering. Children should always work under adult supervision!
Suraj Grewal9 months ago

did everything correctly,used blue leds,any idea why did my avr got hot,and didn't give any time

janw (author)  Suraj Grewal9 months ago
Most of the times when an AVR gets hot, it's because 5v en GND are connected the wrong way round. Or because there is another short circuit somewhere.
Suraj Grewal janw9 months ago

Solved.Thanks Stupid me,a jumper connected to vcc touched gnd,bad insulation

janw (author)  Suraj Grewal9 months ago
That kind of problems happen to us all. Glad that you found the problem.
Dear Sir, Thank you so much for this nice project! I made this clock, and it's really beautiful! But I'm facing a problem. when the clock restarts, the "Second" starts counting from "1" every time. "Hour" and "Minute" are OK. For this reason my clock getting a little bit slow every time I start my PC(it's powered by my PC-USB). Would you fix this for me? Please! thank you!
janw (author)  pavelin_one1 year ago
Hi, you problem is a known one and my own clock has the same problem. Its due to an error I made in the code when I wrote it. Sadly I don't have the code anymore except for the hex-file in this instructable.
If you would like to try to write your own (and ofcourse better) code then I am willing to help you with that so that your clock works perfectly.
It's ok Sir! I'll try to write a new code then. But I need some time. Thank you very much!
troyster842 years ago
Im having an issue with the code its downloading as a temp file. you can post the code or email it to me @ or even tell me what im doing wrong or with program will read it without issues
Nice clock :D Any way to implement this into a watch type thing? D:
mr.space4 years ago
Awesome Techie clock, you got my vote
where can i buy a project kit for this online?
janw (author)  Jimmy Proton4 years ago
I wouldn't know as I made this one on my own but I suggest that you goolge a bit. I am sure that you will find some kits
i didnt find any kits tho
nvm i found one thanks