1. NOTE
the location of pin 1
is printed on the
underside of the matrix
pin 2
resistor
(1K Ohm)
pin 3
resistor
(1K Ohm)
pin 4
resistor
(1K Ohm)
pin 5
resistor
(1K Ohm)
pin 6
resistor
(1K Ohm)
pin 7
resistor
(1K Ohm)
pin 8
resistor
(1K Ohm)
pin 9
resistor
(1K Ohm)
pin 10 pin 11 pin 12 pin 13
analog
pin 0
analog
pin 1
analog
pin 2
analog
pin 3
11
22
33
44
55
66
77
88
99
1010
1111
1212
1313
1414
1515
1616
1717
1818
1919
2020
2121
2222
2323
2424
2525
2626
2727
2828
2929
3030
11
22
33
44
55
66
77
88
99
1010
1111
1212
1313
1414
1515
1616
1717
1818
1919
2020
2121
2222
2323
2424
2525
2626
2727
2828
2929
3030
AA BB CC DD EE FF GG HH II JJ
AA BB CC DD EE FF GG HH II JJ
LED Displays
(8 x 8 LED Matrix)
8 x 8 Bi-Colour
LED Matrix
(common anode)
x1
1K ohm Resistor
(brown-black-red)
x8
The Pieces The Theory & Code
The Circuit
.: Instructions: print out, cut out, get making :.
.: for more details visit: http://tinyurl.com/yhwxv6h :.
The Layout Sheet
The Schematic
LED Matrix
LED Matrix's are great fun, you can create funky patterns, scroll messages, or
create something entirely bizarre. Sadly controlling one is a tad complicated. But
once mastered is easily repeatable.
.: A quick refresher on LED control can be found here tinyurl.com/cmn5nh :.
Matrix Wiring
Each matrix has 128 LEDs (64 Red & 64 Green) however there is noticeably not
256 leads. Instead the LEDs are wired into a matrix. This matrix has the LED's
anodes connected across rows (8 pins) then the red and green LED's cathodes
attached across columns (8 pins each). To light an LED connect it's rows anode
to +5volts, and through a resistor, it's columns cathode to ground. (you can try
this without a micro-controller)
Displaying Images (Scanning)
Now that we can light any LED we choose it's time to move on to displaying a
(small) image. To do this we will use a scan pattern. In the example code we
define a bitmap image (an array of 8 bytes, each bit representing one LED).
Next we scan through this array one byte at a time, displaying one column then
the next. If we do this fast enough (about 1000 times a second) it appears as an
image. It sounds complex but if you download the code and play around it
should quickly become clear. (play around with the delay times to see the flicker)
Example Code
.: Code to test your display a test pattern http://tinyurl.com/yjozkrr :.
.: Code to scroll a message across the display http://tinyurl.com/yl3pc28 :.
More Things to Try
Dislike Red? you can switch to green by shifting the column pins from COL-R to
COL-G. Using too many Digital pins? Try controlling the display using shift
registers (74HC595) tinyurl.com/l43cph or a dedicated display chip (MAX7219)
http://tinyurl.com/4s2oo7 (arduino.cc)
.: Full Datasheet & Pinout http://tinyurl.com/yff4v8u :.
CIRC-21
LED Displays
(8 x 8 Bi-Colour Matrix)
8x8
Matrix
(common anode)
1K Ohm
5-ROW
5-COL-R
6-ROW
6-COL-R
6-COL-G
7-ROW
7-COL-R
7-COL-G
8-ROW
8-COL-R
9-COL-G
5-COL-G
to pin 10
to pin 11
to pin 12
to pin 13
to analog 0
to analog 1
to analog 2
to analog 3
to pin 2
to pin 3
to pin 4
to pin 5
to pin 6
to pin 7
to pin 8
to pin 9
ROW-4
R-COL-4
G-COL-4
ROW-2
R-COL-2
G-COL-2
ROW-1
R-COL-1
G-COL-1
ROW-3
R-COL-3
G-COL-3
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
NOTE
the matrix is larger than
the breadboard. Install the
wires, fold them outwards
then insert the matrix.