How to Make 1-Digit Digital Tube Display Numbers?
1.Introduction
The seven-segment digital tube is an electronic display device that displays decimal numbers. It is widely used in digital clocks, electronic meters, basic calculators and other electronic devices that display digital information. The tubes are an alternative to more complex dot-matrix displays that are easy to use in both limited light conditions and strong sunlight. In this project, we will use the PLUS control board to control 1-digit digital tube to display numbers.
2.Components Required
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Keyestudio Plus Mainboard*1 |
1-digit Digital Tube*1 |
220Ω Resistor*8 |
Breadboard*1 |
Jumper Wires |
USB Cable*1 |
3.Component Knowledge
Display principle: the digital tube display is a semiconductor light-emitting device. Its basic unit is a light-emitting diode (LED). The digital tube display can be divided into 7-segment digital tube and 8-segment digital tube according to the number of segments. The 8-segment digital tube has one more LED unit than the 7-segment digital tube (used for decimal point display). Each segment of the 7-segment LED display is a separate LED. According to the connection mode of the LED unit, the digital tube can be divided into a common anode digital tube and a common cathode digital tube.
In the common cathode 7-segment digital tube, all the cathodes (or negative electrodes) of the segmented LEDs are connected together, so you should connect the common cathode to GND. To light up a segmented LED, you can set its associated pin to“HIGH”.
In the common anode 7-segment digital tube, the LED anodes (positive electrodes) of all segments are connected together, so you should connect the common anode to“+5V”. To light up a segmented LED, you can set its associated pin to “LOW”.
Each part of the digital tube is composed of an LED. So when you use it, you also need to use a current limiting resistor. Otherwise, the LED will be damaged. In this experiment, we use an ordinary common cathode one-bit digital tube. As we mentioned above, you should connect the common cathode to GND. To light up a segmented LED, you can set its associated pin to “HIGH”.
4.Circuit Diagram and Wiring Diagram
Note: The direction of the 7-segment digital tube inserted into the breadboard is the same as the wiring diagram, and there is one more point in the lower right corner.
The digital display is divided into 7 segments, and the decimal point display is divided into 1 segment. When certain numbers are displayed, the corresponding segment will be illuminated. For example, when the number 1 is displayed, segments b and c will be opened. We compile a subroutine for each number, and compile the main program to display a number every 1 second, and display numbers 9 to 0 in cycles. The display time of each number depends on the delay time, the longer the delay time, the longer the display time.
/*
1-digit Digital Tube
http//www.keyestudio.com
*/
// sets the IO PIN for every segment
int a = 7; // digital PIN 7 for segment a
int b = 6; // digital PIN 6 for segment b
int c = 5; // digital PIN 5 for segment c
int d = 10; //digital PIN 10 for segment d
int e = 11; //digital PIN 11 for segment e
int f = 8; //digital PIN 8 for segment f
int g = 9; //digital PIN 9 for segment g
int dp = 4; //digital PIN 4 for segment dp
void digital_0(void) // displays number 0
{
unsigned char j;
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, LOW);
digitalWrite(dp, LOW);
}
void digital_1(void) // displays number 1
{
unsigned char j;
digitalWrite(c, HIGH); // led sets level for PIN 5 to "high", turns on segment c
digitalWrite(b, HIGH); // turns on segment b
for (j = 7; j <= 11; j++) // turns off other segments
digitalWrite(j, LOW);
digitalWrite(dp, LOW); // turns off segment dp
}
void digital_2(void) // displays number 2
{
unsigned char j;
digitalWrite(b, HIGH);
digitalWrite(a, HIGH);
for (j = 9; j <= 11; j++)
digitalWrite(j, HIGH);
digitalWrite(dp, LOW);
digitalWrite(c, LOW);
digitalWrite(f, LOW);
}
void digital_3(void) // displays number 3
{
digitalWrite(g, HIGH);
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(dp, LOW);
digitalWrite(f, LOW);
digitalWrite(e, LOW);
}
void digital_4(void) // displays number 4
{
digitalWrite(c, HIGH);
digitalWrite(b, HIGH);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
digitalWrite(dp, LOW);
digitalWrite(a, LOW);
digitalWrite(e, LOW);
digitalWrite(d, LOW);
}
void digital_5(void) // displays number 5
{
unsigned char j;
digitalWrite(a, HIGH);
digitalWrite(b, LOW);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, LOW);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
digitalWrite(dp, LOW);
}
void digital_6(void) // displays number 6
{
unsigned char j;
for (j = 7; j <= 11; j++)
digitalWrite(j, HIGH);
digitalWrite(c, HIGH);
digitalWrite(dp, LOW);
digitalWrite(b, LOW);
}
void digital_7(void) // displays number 7
{
unsigned char j;
for (j = 5; j <= 7; j++)
digitalWrite(j, HIGH);
digitalWrite(dp, LOW);
for (j = 8; j <= 11; j++)
digitalWrite(j, LOW);
}
void digital_8(void) // displays number 8
{
unsigned char j;
for (j = 5; j <= 11; j++)
digitalWrite(j, HIGH);
digitalWrite(dp, LOW);
}
void digital_9(void) // displays number 9
{
unsigned char j;
digitalWrite(a, HIGH);
digitalWrite(b, HIGH);
digitalWrite(c, HIGH);
digitalWrite(d, HIGH);
digitalWrite(e, LOW);
digitalWrite(f, HIGH);
digitalWrite(g, HIGH);
digitalWrite(dp, LOW);
}
void setup() {
int i; // declares a Variable
for (i = 4; i <= 11; i++)
pinMode(i, OUTPUT); // sets PIN 4-11 to "output"
}
void loop() {
while (1) {
digital_9(); // displays number 9
delay(1000); // waits a sencond
digital_8(); // displays number 8
delay(1000); // waits a sencond
digital_7(); // displays number 7
delay(1000); // waits a sencond
digital_6(); // displays number 6
delay(1000); // waits a sencond
digital_5(); // displays number 5
delay(1000); // waits a sencond
digital_4(); // displays number 4
delay(1000); // waits a sencond
digital_3(); // displays number 3
delay(1000); // waits a sencond
digital_2(); // displays number 2
delay(1000); // waits a sencond
digital_1(); // displays number 1
delay(1000); // waits a sencond
digital_0(); // displays number 0
delay(1000); // waits a sencond
}
}
6.Result
After burning the project code, connecting the wires and powering on, 1-digit digital tube will display numbers from 9 to 0.