Arduino microcomputer system is an affordable platform for learning micro-processing and programming.
Arduino, however, can be used for instruments, meters, robots, and many automated processes.
In this series, we will introduce some basic knowledge of software and hardware interfaces, and I will show you how to build this simple but effective LED matrix display system.
The LED display only needs 30 LEDs of any color, 6x390-
5 × 1N4148 ohm resistance (or 1N914)
Low power diodes, some thin lines and a small piece of perfboard can hold everything.
The total cost could be $5. 00.
Oh yes, you need an Arduino processor for a price ranging from $30 to $50.
Look up, BoArduino and Freeduino, choose one that will appeal to you. Software-
It is wise that they are all compatible and can be exchanged almost.
A major consideration is the "input interface": the method of providing programming and data to the microprocessor.
I highly recommend you to use USB if you are just starting.
With it, not only can you use a normal computer and your micro (
WIndows, Mac, or Linux)
It can also power the microcomputer in a certain range.
One of the newest members of the Arduino family is "nano", as shown in the figure, which tries to say hello on the LED panel.
It has everything on 2 "x 1 (5 x 3 cm)
Have your own USB connection.
Arduino is a complete development system that can be connected to the real world: lights, sounds, motion, and can be connected to sensors that can "perceive" them.
Most importantly, the Arduino Foundation is "open "--
All of its software is free and you are encouraged to share and develop your own software. The LMP is 6-
5-cross columns
A total of 30 LEDs.
The size is selected because this size matrix is the smallest matrix that can be used to display English letters and is wide enough to be used for scrolling messages.
It is also the largest matrix and can only be built using the available output pins on one side of the Arduino package.
Technically: controlled columns from digital pins 2 to 7 (PORTD)
The row uses pins 8 to 12.
This form of matrix addressing means that only one LED can be lit at any time, but we can control 30 LEDs separately without the need for expensive multiplexing and addressing hardware.
Before we start the actual build, take a look at this youtube video and see some of the display features we can use the panel.
Possible (and tempting)
To use LEDs of different colors, it is recommended that you use LEDs with similar voltages: red, ambers and green are in the range of 2 v, while blue, purple and white are more than 3 v.
This avoids the problem of great changes in brightness.
Start with 2 "x 3 (5cm x 7. 5cm)
A perforated circuit board (perfboard)
And arrange the led as shown in the figure.
Shorter alignment (-)
Pointing to the lead at the top of the board, I marked it with an arrow.
Make sure the LED is flat relative to the surface of the board and only weld the negative leads.
All 30 LEDs do this.
The longer the fold now (+)
The leads of each LED come into contact with its neighbors and weld them together.
You should connect the leads of 6 LEDs in this way, all pointing to the right.
You will form a pin directly inserted into the MPC board.
Make sure you can attach them directly to the female title (sockets)
Mark D12 to D8 on a microcomputer board.
The larger MPC board has a gap between the pins D7 and D8;
Make the necessary adjustments to your installation!
Bend the lead of the 5x1n4148 diode to come out of the space at the bottom, the cathode (-)
The ribbon side points to the LEDs. The anode (+)
Micro will be connected to the pin of micro.
If you find wires too fragile as connectors, reinforce them with heavier wires.
Connect the cathode end to the anode of the LED with a thin wire (row)
End: Sales 12, row 1; pin 11, row 2; pin 10, row 3;
Row 4 and row 08, row 5.
To isolate the lead of the LEDs, cut a small piece of perboard to see the connection you have established.
Don't make it bigger than necessary.
Similarly, match the pin connector of the microprocessor with The Matrix.
Some micro-computer boards have an extra space between pins 7 and 8 that you have to take into account.
Join all negative (cathode)
Lead of the vertical led, as shown below.
The installation of 6 resistors matches pin 2 (at the end)
The sixth column of the microprocessor.
Other connections are pin 3 and col 5; pin 4 col 4; pin 5 col 3;
Pin 6 col 2 and pin 7 col 1.
After verifying all the connections and trimming all the ends, the LMP is done!
Quick test is a power supply that connects 3 to 6 volts (
3 or 4 AA batteries)
And touch a row (pins 8-12)and the -to a COLUMN (pins 2-7)
, Should light one and only one LED.
A sentence about resistance selection. The value (390-ohm)
The choice is 8 mA through LEDs.
This may seem low, but the efficiency of the driver makes it unnecessary to use higher power.
Resistance can be as low as 220 if absolutely needed-ohms.
Now, insert LMP if everything is OK, make sure (again)that pins 2 -
12 matches the socket on the Arduino.
Then you can paste the following program and see that your efforts are getting lighter!