Introduction:
This project describes the building and testing of a simple 8 x 8 LED Array Module.
The unit is about 35mm x 35mm and contains 8 rows of 8 LED’s.
Unlike the Matrix E-Block this has dual colour LED’s (Red & Green), but is not able to be multiplexed.
The device is common anode and has a total of 24 pins.
The datasheet is not at first glance overly clear on the connections, but once studied for a few minutes all will be clear.
(Helps if you can read Chinese too )
Hardware:
1 x Oolout LED Array (Costs about £3.00)
2 x 8 Pin SIL Header Sockets
2 x 8 Pin SIL Header Pins
1 x Piece Of Vero-Board to suit
1 x EB 006 Microcontroller Programmer.
3 x 9-PIN D To SIL Header adaptors
Female – Female Jumpers.
Connections:
The device was soldered to a piece of Vero-Board using SIL sockets to allow the module to be removed easily.
Sill Headers are used to allow jumper cables to connect the module to the microcontroller programmer or an Arduino.
The main disadvantage using these sort of connections is a total of 24 data lines (Ports B, C, & D) are needed.
The vertical pin spacing is very slightly different to standard proto-boards / vero-boards etc. To get round this it is possible to bend the pins inward slightly. Horizontal spacing is fine.
Anodes are connected to PORT C on the Microcontroller
- PIC LED
0 11
1 19
2 16
3 13
4 3
5 6
6 9
7 12
Two resistors were used rather than just one on the anode, so both LED’s can be turned on at the same time. (Giving an orange colour). Just using 1 resistor, would allow double the current to flow in each colour if used like this.
PORT D
- PIC LED
0 24
1 21
2 18
3 15
4 1
5 4
6 7
7 10
- PIC LED
0 23
1 20
2 17
3 14
4 2
5 5
6 8
7 11
Some simple test programs were written to verify operation of the module.
Simple Binary Counter
Each row is turned on in sequence, counting from 0 to 255 in binary. (All columns lit) The same program was tried with each column being lit in sequence, again counting from 0 to 255 in binary (All rows lit)
These were repeated using both green and red led’s. A third test was done using both on together.
A set of sample flowcharts for both FC5 and FC6 are attached below.
Using a shift register such as a 74HC595 will allow the device to be driven with less data lines.
Video Link:
A simple video captured with my Smartphone showing the operation.
http://youtu.be/Iah2zRzs_8M
- LED_Matrix.jpg (44.86 KiB) Viewed 23588 times
- CloseUp.jpg (96.5 KiB) Viewed 23587 times
