Fortuneomg

LED Display 7 Segment 2 Digit 0.56 inch Common Cathode Ultra Red 15524 ucd.

Introduction

Large numerical displays are a great addition to any project where you want to be able to see information at a distance. Scorekeepers and lap timers would be a great application for large 7-segment LED displays. The Really Big 7-Segment Display (6.5') fits that bill nicely. Driving several displays at the same time would be handy, which is where the Large Digit Driver board comes in.

The Large Digit Driver can be soldered directly to the bottom of the 7-Segment Display.

Several Large Digit Drivers can be chained together to create a display with multiple digits.

Covered in This Tutorial

In this tutorial, we will give you an overview of the Large Digit Driver and provide an example of hooking up the driver to an Arduino:

• Board Overview -- To begin, we'll go over each of the pins on the breakout board and their function.
• Hardware Hookup -- In this section, we'll show you how to hook the Large Digit Driver up to an Arduino.
• Example: One Large Digit -- Here, we give an example of an Arduino sketch to control one of the large 7-segment displays through the Large Digit Driver.
• Example: Two Large Digits -- We show how to daisy chain two large 7-segment displays together and control them with two Large Digit Drivers.
• Resources and Going Further -- This section gives some additional resources for getting more out of the Large Digit Driver.

Materials Used

You will need a few components and tools to follow along with this tutorial. Here is what you will need:

For each additional digit you want to add, you will need:

Recommended Reading

Before getting started with the Large Digit Driver, there are a few concepts that you should be familiar with. Consider reading some of these tutorials before continuing:

• What is an Arduino? -- We will use an Arduino to control the Large Digit Driver
• Shift Registers -- The Large Digit Driver uses a shift register to move data to each digit
• How to Solder - Castellated Mounting Holes -- You will need to solder the Large Digit Driver to the back of the 7-segment LED display

What is an Arduino?

Shift Registers

How to Solder: Castellated Mounting Holes

Board Overview

Pin Descriptions

The Large Digit Driver has 6 input pins and 6 output pins.

Hardware Hookup

Protect the Board

Before you attach the Large Digit Driver to the 7-segment display, you will need to isolate the exposed vias on the back of the board. Some of the Driver boards are created with through-hole vias that are not covered with solder mask. As a result, this could likely short out the traces on the back of the 7-segment display.

We recommend using a piece of electrical tape or high temperature tape to cover the vias on the back of the Driver board.

Attach the Board

You will need to solder the Large Digit Driver to the back of the 7-segment display. Have the Driver's 10 pins facing toward the bottom of the large 7-segment display and lined up with the traces on the back of the 7-segment display. Follow the Soldering Castellated Vias Guide to solder all 10 of the castellations as well as the 2 castellations at the top of the board (these should be attached to the 12V line and are just for mechanical support).

Connect the Board

We will be using the Arduino's regulated 5V and unregulated 12V (from the wall adapter) to power the 7-segment display and Large Digit Driver.

Connect the Large Digit Driver to the the following pins on the Arduino.

Example: One Large Digit

Note: This example assumes you are using the latest version of the Arduino IDE on your desktop. If this is your first time using Arduino, please review our tutorial on installing the Arduino IDE.

Load the Single Digit Example Code

Plug your Arduino into your computer via USB cable. Open up the Arduino program and copy in the following sketch.

Run

Upload the sketch to your Arduino, and plug the 12V adapter into the Arduino.

Flip the 7-segment display over. You should see it count the digits 0-9 (the decimal point will appear on 9).

Example: Two Large Digits

Attach a Second Digit

Use the 6-pin jumper wire to attach a second 7-segment display to the first display unit. Make sure that you connect GND of the OUT on the first display to the GND of the IN on the second display, LAT of the OUT on the first display to the LAT of the IN on the second display, and so on.

Load the Two Digit Example Code

Make sure the Arduino is plugged into your computer using a USB cable. Copy the following sketch into the Arduino program.

Run

Upload the sketch to your Arduino, and plug in the 12V supply. The 7-segment display (now two digits!) should count from 00 to 99.

Example: Speed Trap

To demonstrate the displays we built a device that measures the distance from the wall to a human. As that distance changes we can caculate speed. We present: The SparkFun Speed Trap!

Here is a list of parts you'll need:

You can find the code and the PCB layout for the Speed Trap here. You don't need the custom PCB, it's fairly easy to build just with jumpers and a bit of soldering.

Resources and Going Further

Now that we have tested the large 7-segment displays, they are ready to be used in your project! Feel free to change the code to display other numbers or symbols on the displays.

Resources

Here are some additional resource to help you with the Large Digit Driver:

Check out this tutorial that a customer created for using the large digit display driver with a Raspberry Pi:

Other Tutorials

What will you make with the Large Digit Driver? If you need some inspiration, check out these related tutorials:

Dungeons and Dragons Dice Gauntlet

Interactive Hanging LED Array

Alphanumeric GPS Wall Clock

A seven-segment display (SSD), or seven-segment indicator, is a form of electronic display device for displaying decimalnumerals that is an alternative to the more complex dot matrix displays.

Seven-segment displays are widely used in digital clocks, electronic meters, basic calculators, and other electronic devices that display numerical information.^[1]

Concept and visual structure[edit]

The seven elements of the display can be lit in different combinations to represent the Arabic numerals. Often the seven segments are arranged in an oblique (slanted) arrangement, which aids readability.^{[citation needed]} In most applications, the seven segments are of nearly uniform shape and size (usually elongated hexagons, though trapezoids and rectangles can also be used), though in the case of adding machines, the vertical segments are longer and more oddly shaped at the ends in an effort to further enhance readability.

The numerals 6 and 9 may be represented by two different glyphs on seven-segment displays, with or without a 'tail'.^[2][3] The numeral 7 also has two versions, with or without segment F.^[4]

The seven segments are arranged as a rectangle of two vertical segments on each side with one horizontal segment on the top, middle, and bottom. Additionally, the seventh segment bisects the rectangle horizontally. There are also fourteen-segment displays and sixteen-segment displays (for full alphanumerics); however, these have mostly been replaced by dot matrix displays. Twenty-two segment displays capable of displaying the full ASCII character set^[5] were briefly available in the early 1980s, but did not prove popular.

The segments of a 7-segment display are referred to by the letters A to G, where the optional decimal point (an 'eighth segment', referred to as DP) is used for the display of non-integer numbers.^[6][7]

Implementations[edit]

Seven-segment displays may use a liquid crystal display (LCD), a light-emitting diode (LED) for each segment, an electrochromic display, or other light-generating or controlling techniques such as cold cathode gas discharge (Panaplex), vacuum fluorescent, incandescent filaments (Numitron), and others. For gasoline price totems and other large signs, vane displays made up of electromagnetically flipped light-reflecting segments (or 'vanes') are still commonly used. An alternative to the 7-segment display in the 1950s through the 1970s was the cold-cathode, neon-lamp-like nixie tube. Starting in 1970, RCA sold a display device known as the Numitron that used incandescent filaments arranged into a seven-segment display.^[8]

In a simple LED package, typically all of the cathodes (negative terminals) or all of the anodes (positive terminals) of the segment LEDs are connected and brought out to a common pin; this is referred to as a 'common cathode' or 'common anode' device.^[7] Hence a 7 segment plus decimal point package will only require nine pins, though commercial products typically contain more pins, and/or spaces where pins would go, in order to match standard IC sockets. Integrated displays also exist, with single or multiple digits. Some of these integrated displays incorporate their own internal decoder, though most do not: each individual LED is brought out to a connecting pin as described.

Multiple-digit LED displays as used in pocket calculators and similar devices used multiplexed displays to reduce the number of I/O pins required to control the display. For example, all the anodes of the A segments of each digit position would be connected together and to a driver circuit pin, while the cathodes of all segments for each digit would be connected. To operate any particular segment of any digit, the controlling integrated circuit would turn on the cathode driver for the selected digit, and the anode drivers for the desired segments; then after a short blanking interval the next digit would be selected and new segments lit, in a sequential fashion. In this manner an eight digit display with seven segments and a decimal point would require only 8 cathode drivers and 8 anode drivers, instead of sixty-four drivers and IC pins.^[9] Often in pocket calculators the digit drive lines would be used to scan the keyboard as well, providing further savings; however, pressing multiple keys at once would produce odd results on the multiplexed display.

Although to a naked eye all digits of an LED display appear lit, the implementation of a typical multiplexed display described above means that in reality only a single digit is lit at any given time.

A single byte can encode the full state of a 7-segment-display. The most popular bit encodings are gfedcba and abcdefg, where each letter represents a particular segment in the display. In the gfedcba representation, a byte value of 0x06 would (in a common anode circuit) turn on segments 'c' and 'b', which would display a '1'.

History[edit]

Seven-segment representation of figures can be found in patents as early as 1903 (in U.S. Patent 1,126,641), when Carl Kinsley invented a method of telegraphically transmitting letters and numbers and having them printed on tape in a segmented format. In 1908, F. W. Wood invented an 8-segment display, which displayed the number 4 using a diagonal bar (U.S. Patent 974,943). In 1910, a seven-segment display illuminated by incandescent bulbs was used on a power-plant boiler room signal panel.^[10] They were also used to show the dialed telephone number to operators during the transition from manual to automatic telephone dialing.^[11] They did not achieve widespread use until the advent of LEDs in the 1970s.

They are sometimes used in posters or tags, where the user either applies color to pre-printed segments, or applies color through a seven-segment digit template, to compose figures such as product prices or telephone numbers.

For many applications, dot-matrix LCDs have largely superseded LED displays, though even in LCDs 7-segment displays are very common. Unlike LEDs, the shapes of elements in an LCD panel are arbitrary since they are formed on the display by a kind of printing process. In contrast, the shapes of LED segments tend to be simple rectangles, reflecting the fact that they have to be physically moulded to shape, which makes it difficult to form more complex shapes than the segments of 7-segment displays. However, the high common recognition factor of 7-segment displays, and the comparatively high visual contrast obtained by such displays relative to dot-matrix digits, makes seven-segment multiple-digit LCD screens very common on basic calculators.

The seven-segment display has inspired type designers to producetypefaces reminiscent of that display (but more legible), such asNew Alphabet (typeface),'DB LCD Temp','ION B',etc.

Displaying letters[edit]

Hexadecimal digits can be displayed on seven-segment displays. Today, a combination of uppercase and lowercase letters is commonly used for A–F;^{[12][13][14][15]} this is done to obtain a unique, unambiguous shape for each hexadecimal digit (otherwise, a capital 'D' would look identical to a '0' and a capital 'B' would look identical to an '8'). Also the digit '6' must be displayed with the top bar lit to avoid ambiguity with the letter 'b'.^{[12][13][14][15][3]}

However, this modern scheme wasn't always followed in the past, and various other schemes could be found as well:

• The Texas Instruments seven-segment display decoder chips 7446/7447/7448/7449 and 74246/74247/74248/74249 and the Siemens FLH551-7448/555-8448 chips used truncated versions of '2', '3', '4', '5' and '6' for digits A–E. Digit F (1111 binary) was blank.^[3][16][17]
• Soviet programmable calculators like the Б3–34 instead used the symbols '−', 'L', 'C', 'Г', 'E', and ' ' (space) to display hexadecimal numbers above nine, allowing the error message EГГ0Г to be displayed.
• Not all 7-segment decoders were suitable to display digits above nine at all. Many earlier chips provided logic designed for only for 0–9 and higher numbers produced whatever pattern resulted. For comparison, the National Semiconductor MM74C912 displayed 'o' for A and B, '−' for C, D and E, and blank for F. The CD4511 even just displayed blanks.

In addition, seven-segment displays can be used to show various other letters of the Latin, Cyrillic and Greek alphabets including punctuation, but few representations are unambiguous and intuitive at the same time.^[18] Short messages giving status information (e.g. 'no dISC' on a CD player) are also commonly represented on 7-segment displays. In the case of such messages it is not necessary for every letter to be unambiguous, merely for the words as a whole to be readable.

Similar displays with fourteen or sixteen segments are available allowing less-ambiguous representations of the alphabet.

Using a restricted range of letters that look like (upside-down) digits, seven-segment displays are commonly used by school children to form words and phrases using a technique known as 'calculator spelling'.

See also[edit]

References[edit]

1. ^'Seven Segment Displays'. Archived from the original on 2012-04-04.
2. ^Nührmann, Dieter (1981). Written at Achim, Bremen, Germany. Werkbuch Elektronik (in German) (3 ed.). Munich, Germany: Franzis-Verlag GmbH. p. 695. ISBN3-7723-6543-4.
3. ^ ^abcBCD-to-Seven-Segment Decoders/Drivers: SN54246/SN54247/SN54LS247, SN54LS248 SN74246/SN74247/SN74LS247/SN74LS248(PDF), Texas Instruments, March 1988 [March 1974], SDLS083, archived(PDF) from the original on 2017-03-29, retrieved 2017-03-30, […] They can be used interchangeable in present or future designs to offer designers a choice between two indicator fonts. The '46A, '47A, 'LS47, and 'LS48 compose the 6 and the 9 without tails and the '246, '247, 'LS247, and 'LS248 compose the 6 and the 0 with tails. Composition of all other characters, including display patterns for BCD inputs above nine, is identical. […] Display patterns for BCD input counts above 9 are unique symbols to authenticate input conditions. […]
4. ^For example the fx-50F calculator from Casio and other models from the same manufacturer.
5. ^'DL-3422 4-digit 22-segment alphanumeric Intelligent Display™ preliminary data sheet'. Internet Archive. Litronix 1982 Optoelectronics Catalog. p. 82. Retrieved 2016-09-03.
6. ^'Seven Segment Displays'. Archived from the original on 2012-01-05. Retrieved 2012-11-14.
7. ^ ^abElektrotechnik Tabellen Kommunikationselektronik (3rd ed.). Braunschweig, Germany: Westermann Verlag. 1999. p. 110. ISBN3142250379.
8. ^'Advert for RCA NUMITRON Display Devices'. Electronic Design. Hayden. 22 (12): 163. 1974-06-07.
9. ^e.g. DCR 1050m
10. ^Rogers, Warren O. (1910-02-01). 'Power Plant Signalling System'. Power and the Engineer. 32 (5): 204–206.
11. ^Clark, E. H. (December 1929). 'Evolution of the Call-Indicator System'(PDF). Bell Laboratories Record. 8 (5): 171–173.
12. ^ ^abcd'Driving 7-Segment Displays'. Maxim Integrated. 2004. Archived from the original on 2017-03-20. Retrieved 2017-03-20.
13. ^ ^abcdelectronic hexadecimal calculator/converter SR-22(PDF) (Revision A ed.). Texas Instruments Incorporated. 1974. p. 7. 1304-389 Rev A. Archived(PDF) from the original on 2017-03-20. Retrieved 2017-03-20.
14. ^ ^abcelectronic calculator – TI programmer(PDF). Texas Instruments Incorporated. 1977. p. 7. Archived(PDF) from the original on 2017-03-28. Retrieved 2017-03-28.
15. ^ ^abcelectronic calculator – TI LCD programmer(PDF). Texas Instruments Incorporated. 1981. p. 8. Archived(PDF) from the original on 2017-03-28. Retrieved 2017-03-28.
16. ^Beuth, Klaus; Beuth, Annette (1990). Digitaltechnik. Elektronik (in German). 4 (7 ed.). Würzburg, Germany: Vogel Buchverlag [de]. pp. 301–303. ISBN3-8023-0584-1.
17. ^Datenblatt FLH551-7448, FLH555-8448, 74248 (in German). Siemens.
18. ^Downie, Neil A. (2003). Ink Sandwiches, Electric Worms and 37 Other Experiments for Saturday Science. Johns Hopkins University Press. p. 271.

External links[edit]

7 Segment Led Display Driver

6 Digit Led Display Driver S