Archive for the ‘time’ Category

Fully Independent DS3231 RTC Breakout Board

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This is the DS3231 breakout board that I designed for my nixie tube clock. The DS3231 is a cool Real Time Clock (RTC) chip from Maxim that keeps track of the time, date, two alarms, and outputs the current temperature.  The chip has an internal oscillator which allows it to be very precise. And, the chip can run at very low power off a battery backup and keeps time for 6-7 years when the power goes off.  Sounds cool, right? However, the one drawback is that the IO pins require external pull-up resistors and many of the breakout boards (like say, the ChronoDot) on the market don’t include them.  So I decided to make my own breakout board with proper pull-up resistors on all the pins, appropriate de-coupling capacitors, and a on-board battery backup. This makes the board fully independent and pluggable into any project without requiring additional components. The board is slightly taller than a quarter and works great in my nixie tube clock. In the future I should be able to port it other projects. The layout follows the datasheet and I tried to keep a nice solid ground plane under the chip. I used surface mount components to reduce board size but used larger 1206 size components for easy soldering.



In Action – Plugged into my Nixie Tube CPU board:

DS3231 breakout board

Breakout board in action

Parts List:

Part Value Package Digikey Part #
C2 0.1F 1206 445-4024-1-ND
IC1 DS3231SN SOIC 16W DS3231S#-ND
JP1 Jumper A26525-40-ND
R1, R2, R3, R4 10k Ohm 1206 RHM10.0KFRCT-ND
U$7 Battery Holder CR1220-SMD 3000K-ND

Eagle layout files:

Update 12/29/2014:

Forget building your own board.  You can get the DS3231 on a PCB for about $4.50 direct from China through Amazon.  You’ll save yourself a lot of time and hassle and the pinout even looks to be Arduino compatible.  Link here.

Written by M Kapoor

January 27, 2012 at 4:45 am


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Have you ever wondered what you do all day? On average, I spend about 9 hours a day at work and I often switch between many tasks. At the end of the day I sometimes wonder about what I did! So, I was very interested when I found rescuetime the other day while surfing around on the web. Rescuetime promises to help you manage your time better by letting you track exactly what you are working on. They do this by have a little taskbar application that you download and run in the background. The application tracks your active windows during the day and sends the data to the RescueTime servers. They then summarize the data and turn it into into pretty little flash bargraphs. The graphs show a variety of data, almost every imaginable combination is shown. You can see how much time you spend using each application, you can check your time by application category, and you can view the percentage of time you spend at your computer per hour across a chosen interval. All this information is available by day, month, year or for all time. It is a pretty nifty tool, you can even configure alerts and goals to change your usage. Also, they encourage the use of their API to create new applications.

I’ve been using RescueTime for about a month now and I’ve noticed that my top 3 categories are ‘Dev Tools’, ‘Comm (Email)’, and ‘News/Blogs’. Now, using dev tools and e-mail are part of my job. However, ‘News/Blogs’ is pure web surfing!

Top Categories for May

I counted up all the other categories and I noticed that I spent almost 20 hours in the past month online doing things other than work. Of course, some of these activites are off work hours and I often work extra so I don’t think the time spent is very worrisome. However, it is a siginficant drain on my productivity during the day since I constantly switch in and out of a browser window.

I was nodding recently as I read Paul Graham’s essay on Disconnecting Distraction and I wholly agree with with his assertion on how distracting the internet has become. As a result, I’m going to try out his idea of using my work computer only for work and my home computer for play. In order to do this, I’m going to remove all the applications that distract me – like my browser and my rss feed reader. I expect it to be difficult at first, however, I think that over time I’ll adjust and become more productive … I hope 🙂

Written by M Kapoor

May 30, 2008 at 3:39 pm