Project BAC v.1.1
This post is about a project that took ages to built and I manage to loose in an unfortunate circumstances…
I always wanted to build a clock. And this is what came up…
The Idea
Create a modular clock that has interchangeable displays.
The Execution
Main controller
The main module for the clock is an ATmega328 microcontroller with a DS1307 Real Time Clock. The LCD displays current date and temperature as well as shows the setup menu.
Interaction with the clock is done by one rotary encoder that has a built-in push button. The state diagram for the menu can be found below.
Display Controllers
Time display (described below) is controller by a series of 74HC595 shift registers. Since there is a need for two digits per segment (by segment I mean hours, minutes and seconds) there are 6 of them in total connected in series. To update the time display I have to shift out the current state of the hours, minutes and seconds every second. Since the update rate is relatively slow no stress is applied to the microcontroller and it can do other tasks like displaying temperature readings, etc.
Time display
Time is displayed on a self-built 7 segment displays. There are 3 LED’s for the horizontal axis and 4 for the vertical one. By testing various combinations I found that this setup was the most appealing to my eyes. LED’s in a segment are connected in parallel and routed to the input connector at the bottom of the board (color-coded cable in the photo). The only problem I had with the displays was that they were really bright even on the lowest brightness setting (that can adjusted through the menu). To mitigate this problem I added some plexiglass that I painted white to diffuse the light a bit. Note to myself for the future projects: do not use clear LED’s for such applications…
More photos
A short clip showing the testing of the time display
Conclusion
I had a lot of fun working on this project. It was a really nice learning experience and I am planning on rebuilding the project in the future with some improvements.
Posted on May 4, 2013, in Electronics, Projects and tagged arduino, atmega, atmega328, clock, LCD. Bookmark the permalink. 4 Comments.
Vaidas Sirtautas' Blog 
What’s up to every body, it’s my first visit of this webpage; this web site carries amazing and really fine stuff in favor of visitors.
An intriguing discussion is definitely worth comment.
I do think that you need to publish more on this subject, it may not be a taboo subject but typically people don’t speak about such issues.
To the next! Kind regards!!
This is the right site for anyone who really wants to understand this topic.
You understand so much its almost tough to argue with you (not that
I personally would want to…HaHa). You definitely put a
fresh spin on a subject which has been written about for ages.
Excellent stuff, just great!
Hmm it looks like your site ate my first comment (it was extremely
long) so I guess I’ll just sum it up what I had written and say,
I’m thoroughly enjoying your blog. I as well am an aspiring blog blogger but I’m still new to everything.
Do you have any tips and hints for newbie blog writers?
I’d really appreciate it.