Instructables
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Picture of A simple USB-powered binary clock
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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:

Picture of What do you need:
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  • 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!

dear sir, i make this clock, but the clock isn't works,even if the led don't glow. can you help me. first time when i power on the board the rtc get hot.Then i pull out the cmos battery-solved. i make a modification the circuit- connect the avcc and aref then i insert the battery and power up the problem solved with rtc,but the led don't glow.......

Would you fix this ,sir

sorry for poor English

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janw (author)  albinvadakkekara5 months ago
Hi,

Congrats on your build, it looks nice! The clock needs USB and battery to work. Are all you ic's inserties in the correct direction? Overheating often means that polarities are switchen.

Contact me if it isn't one of the above

Sir,

I checked the pcb several time whether the ic is in correct direction. The ic are perfectly placed.Also i checked the pcb track,its fine. I attach the photo of the board along with this. I made a connection modification--avcc and aref connect to the +5v to overcome the heating problem of the rtc(red wire).(mentioned above).

Is the hex code is working???

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janw (author)  albinvadakkekara5 months ago

avcc is indeed better connected to +5V but it shouldn't solve an overheating rtc. If it does, it means that there in something else wrong in the powerlines of the circuit. The hex-file works perfectly, I reloaded it into my clock and it seems to work good. only thing I don't remeber is whether the internal osc of the atmega should be set to 1Mhz or 8Mhz.

How can i change the internal osc to 1mhz or 8mhz?.....I connect the usb power to my clock the rtc get overheated now. When i remove the cmos battery it will solve the problem.While inserting the battery the rtc get overheated.

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

janw (author)  Suraj Grewal1 year 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.

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

janw (author)  Suraj Grewal1 year 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!
troyster843 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 @ troyster84@rogers.com or even tell me what im doing wrong or with program will read it without issues
Thanks
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