Thursday, April 8, 2010

Countdown timer prototype

While waiting for an 8MHz resonator to finish a previous project and post the result, I put together a prototype of a countdown timer that shows the time passing by changing the display color from green, through orange, to red.

This is just a different way to display information, color versus digits, similar to analog vs digital speedometer, if you will.

The timer is built with an Arduino Diecimila (with ATmega168) and the LED matrix shield.


  1. Is there any reason why this would not work on a wiseduino? Or might there be something up with my wiseduino? The top line of LEDs does not show.


  2. It should work on Wiseduino just as well.
    I would check if pin D8 is connected to the first row of the LED matrix (through the darlington transistor in ULN2803).
    Does the same shield work fine with the Wise Clock sketch (for example)? (Modify the definition of a character to include the top row.)

  3. The wiseduino does not want to work with the wise clock sketch either. I get some scrolling (kinda) bars in green and then when I press the menu button it all goes red. Then comes back on orange.

    All without the top line working either...

    The wiseduino is working fine for other things. Seems to work for scrolling text on the RG dual matrix but the top line is not ever filled by text so that may not be working either. It also works for my rMP3 board (needs pins 6 and 7).

    I will triple check all of the connections. I will check D8, and connections to that, in detail.