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Totally Stuck on LEDs (Bulbdial)

neodemneodem
edited January 2013 in Clock Kits
Could use some help. My girlfriend is working on the Bulbdial clock kit and she's up to the green LED ring. This is her first time working on a project and she's done a great job soldering. 

The Blue ring works perfectly. However, the green LEDs are a mess. When we go into the test mode we get the first LED to light and then maybe about 4 more along the way (in different segments). 

Need some help determining the issue. 

I've checked all of the LEDs and they appear to be functional (used a meter on continuity mode to test each one and they all seemed to work fine). I've checked all of the 0 ohm connections and they seem ok as well (using a continuity test) and I've checked all of the solder connections.

I'm a beginner with charlieplexing but I've read up on it a little bit so I'm wondering if there is a way to fire up the meter and test each bank/led for the correct impedance/voltage at various points. I'm hoping to use that to diagnose the issue. I don't want to de-solder the whole green board.. 

Any ideas on what we should do next?

Comments

  • Windell OskayWindell Oskay
    There are a few things that you should check. First, check that all of the LEDs are facing the same way. There is a "collar" around the base of each LED, on which is one flat facet. Check that all of those facets are facing the same way. 


    The charlieplexing scheme for the Bulbdial is described in some detail in this article:
    http://www.evilmadscientist.com/2010/on-the-design-of-the-bulbdial-clock/ ;

    Each green LED is connected between one of LED1-LED6 and one of LED7-LED9.   Check to make sure that all of R1-R10 are inserted properly, and to make sure that there are no accidental connections between the LED lines-- you can check at the vertical jumpers.   You may also want to read the detailed schematic, to trace between the microcontroller pins and each of the vertical LED lines, to make sure that the correct amount of resistance is between them.


  • neodemneodem
    Thank you. I'm going to start digging now. 
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