Parts to build a front display:
The FLD circuit board
MAX7219 driver IC
24-pin DIP socket
24k resistor
10uF capacitor
0.1uF capacitor
screw terminal
3-pin double-row pin header
(17) blue LEDs
(28) white LEDs
Before you begin: if you're new to soldering, here's an excellent video that will help you get started.
Start by inserting the DIP socket. Make sure it is oriented the right way (align the notched end of the socket with the little "notch" drawn on the board).
I like to tape the socket to the board to keep it in place while I solder it.
The socket pins sticking thru the bottom of the board. Go ahead and solder all the pins. Don't insert the IC yet.
Next, insert the double-row pin header.
Again I've stuck it in place with tape while I solder
Next comes the screw terminal
Now for the resistor. Bend the leads as shown,
insert it into the holes in the board,
and bend the leads on the back so it wont fall out.
Note: The FLD takes a 24k resistor. Later, when you do the RLD, you'll need a 28k resistor for it.
Solder it and then clip off the excess leads.
Go ahead and insert the two capactors
Bend back the leads. Solder.
Now you're ready to start inserting LEDs. I clipped the leads short before inserting into the board.
Here's how you can tell how to orient the LED. Holding like shown in the picture (below), the lead on the left is the cathode. Make sure you put the cathode in the correct hole as indicated in the picture above. Update 5/20/11: One builder (Capodimusica) has reported that some LEDs do not follow this convention, and have the anode/cathode reversed. You can always count on the shorter lead to be the cathode, so double-check it before you clip the leads short.
This is the most time consuming part, but keep at it until you have all the LEDs inserted. Don't solder them until after you've done the checkout. Also, if you're using a bezel, you'll want to fit the bezel before you solder them in.
Now you can go ahead and insert the driver IC in the socket.
Here's a 14-inch 3-wire F/F extension cable (item code 805-00002) from parallax.com. I'm not sure why they call this an extension, because it's female on both ends. Anyway, we'll need to change one end to male by inserting a 3-pin header.
This is how we change one end to male; this is the end that gets inserted into the Arduino.
Attach the female end of the cable to the row of pins marked "IN". The white wire should be on the "L".
Insert the male end into the Arduino; for this demo I have chosen pins 10,11 and 12. The white wire is on pin 10.
Locate a wire pair that you can use to supply 5V to the display board. Insert it in the terminal and tighten the screws. Make sure you get the polarity right; I'm sure nothing good will happen if you reverse it.
Connect the other end to 5V power; in this case I'm just using the 5V supplied by the Arduino.
Here's an overview shot of the whole setup. Note the display board is still sitting face-down.
And finally, power up your Arduino and load the checkout sketch (see below). This is just a simple random blinking. Since the LEDs aren't soldered yet, occasionally one or two won't light up; if this happens, you can usually wiggle it slightly to get it going.
Troubleshooting: if any LEDs are staying on constantly instead of blinking, you probably have it inserted the wrong way (you have the anode and cathode reversed). Try turning it around.
