4. LED_Array


Column resistors:


R1 - R16 100 ohm resistors


Column transistors:  As with Q17, orientation matters. The silk screen indicates the correct orientation. We find that using the middle hole is easier than using the offset hole.


Q1 - Q16 2N5401 


LEDs:  This is a bit tedious, but, compared to ClockTWO this is a complete joy.  A few hours of patience and you will will have the electronics done.  Don't be in a hurry.  I lost an hour during this proceedure when I had to go back two rows to replace an LED.

Before you begin install the six standoffs with the spacers as shown.  This will provide the height standard for the top of the LEDs.  

Gotcha! Check that all six standoffs are touching the table before you begin soldering a column.

You should notice that the LEDs are not flush against the board.

Solder the LEDs one column at a time.  Test each column before moving on to the next.  It is much easier to replace an LED on the edge than in the middle.  These are very high quality LEDs and so far we have not discovered a single bad one many bad ones.  We recently found two LEDs that did not have functioning green.  Hooray for the maker BETLUX!

MOVE LED_ENABLE jumper to bottom two pins to enable the LEDs.

To test the columns: Upload the program Test02.pde to the ATMEGA.  This cycles through all of the colors.  Make sure all the LEDs are functional before moving to next row.  Look for solutions to issues in the hints section.


160 RGB LEDs 01D01 - 10D16

32 Mono LEDs 11D01 - 12D16.

LED Hints and Lead bending :

UPDATE! If you leave the board plugged in and running Test2 while you are inserting the LEDs, you can see if they work and are in the right direction.  Keep in mind that since the unsoldered connections are tenacious at best, you may see some flicker and discolouration.  If you are in the slightest doubt, recheck all the colors of the LED before soldering it in.

The RGB LED leads are: Green, Blue, Common Anode, Red.  The longest lead is the anode.

It gets hard to tell the anode after bending the leads.  I clip the green lead short so I can keep track of it.

Looking from the top of the LED, you will bend the leads thus:

Green o

               o Blue

Anode o

               o Red

Test that you have the correct anode by placing the C3032 battery to positive on anode, negative on red.

The mono LEDs are soldered with the anode (long lead) on top.

After inserting a column of LEDs, flip board over and tap the leads until all of them are flush against the table.

Solder one pin on each LED, flip and check height and alignment (reheat and adjust if necessary).  When happy, solder remaining leads.

Issues and solutions:

  • Nothing lights up
    • Check power LED is lighted.
    • Repeat Blink test.
    • Check that LED_ENABLE jumper is on lower two pins.
  • Single LED does not light up.
    • Check each each solder joint. (Touch up if necessary.)
    • Check that leads are in correct order.
    • Replace if still not working.

  • Single LED is wrong color.
    • Check lead order.

Bending the RGB LED Leads :

RGB LEDs lead bending

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