Tuesday, January 25, 2011

Introducing Wise Clock 3

Updated June 24, 2011: Read this post on the latest code release. Lots of new features added, plus video showing them in action.

Updated March 1, 2001: added schematic and Eagle files.

This latest member of Wise Clock family has two major improvements over its predecessor:
  • the real time clock is upgraded to one of the best RTC chips available, the extremely accurate (±1 minute per year), temperature compensated, DS3231 from Maxim (also used in Chronodot);
  • the LED display, from Sure Electronics, is bigger (32x16 pixels) and better (red, green and yellow pixels).

The main board, shown below, also features:
  • ATmega644P microcontroller running at 16MHz, with the Arduino/Sanguino bootloader;
  • SD card socket;
  • piezoelectric buzzer;
  • three function buttons and one reset button;
  • battery backup for the real time clock (it keeps the time even when the board is not powered);
  • headers that plug directly into the 2x8 connectors in the back of the display, so that a ribbon cable is not required;
  • a small prototyping area, to extend clock's functionality (e.g. adding infrared remote control, FM radio, dimming on the ambient light etc);
  • ICSP 6-pin header;
  • power through USB miniB connector;
  • 6-pin FTDI connector, compatible with the FTDI cable and the FTDI breakout;
  • all 4 ports of the microcontroller (32 pins) are accessible to a "shield"-like expansion board;
  • ability to cascade a second 3216 display through 2x8 pin header (plus ribbon cable);
  • blue power LED.

A few design considerations:
  • the main board fits perfectly within the dimensions of the LED display;
  • the function buttons are accessible from the top, as is the SD card;
  • power connector (USB miniB) accessible from a side;
  • FTDI header placed at the bottom of the board (does not take lateral space);
  • between the main board and the display board there is room left for air circulation, in case the display chips get warm;
  • buzzer placed close to the edge of the board;
  • enclosure made of two laser-cut plexiglass plates, sandwiches the two boards (main and display) together, held in place with a few screwed standoffs.

The software for Wise Clock 3 is being adapted and expanded from Wise Clock 2, with the addition of new features (Pong clock, temperature display etc). The HT1632 files (h and cpp) for the new 3216 LED display are already tested and proven (see this Arduino forum thread).
As always, I will keep you posted. Stay tuned.

Eagle files can be downloaded from here: schematic, board layout.
The schematic is also shown in the image below.


  1. And now then... when can I buy one? :-p

  2. Jeroen, thanks for asking :)
    I just want to have the software done before I offer a complete Wise Clock 3 kit for sale.
    If you want to play around with it and work on the software on your own, send me an email (I will offer a discount :).

  3. Tnx, but I'm not a genius in that stuff. I can do some tings in C,VB,... but noting to fancy.

    Do you have a time frame? (that I have something to look forward to)

  4. You don't need to be a genius (look at me:)
    I really hope to have a working version by this coming Monday. I just have to start working on it over the weekend, now that I have everything in place.

  5. great clock.
    how hard would it be to program the game of life
    and have it run in the backround or after a preset time. i think it would look cool.

  6. bob, thanks.
    Game of life is already one of the menu choices, so it's already implemented. It runs without displaying the time though, unlike pong, for example, which combines the game with the time display.
    Check out the previous post ("Experimenting with 3216 display"), that has the video of the bi-color game of life.

  7. Got linked here from Hack-a-day, and saw the video there. I love how the minute changed when the minutes side 'scored'.

    Put me on the list for a kit. I am 'favorite-ing' this page. :)

  8. volkemon, thanks. You are on the list :)

  9. How do I go about purchasing one of these?

  10. Here is the link for buying the Wise Clock 3 kit:

    And this is the link to the store, where you can buy other kits: http://timewitharduino.blogspot.com/2009/07/shoppe.html

  11. Awesome as well. Torn apart deciding which to buy. Maybe both. We'll see.

    There is another store that offers displays that are cool as well.




    it would be great to see this on the big matrix. I don't know how to program yet, but looks like I will have to start. Any suggestions?


  12. Tom, I've seen the bigger (64x16) displays. Someone mentioned they are made by Sure Electronics exclusively for "Embedded Adventures".
    You can "make" the big display by combining 2 32x16 displays from Sure, I would think.
    I may try to do that in the near future.