14 Segment Display

Episode 379https://www.adafruit.com/product/1912. 7-Segment Display Interfacing With STM32 – LAB. STM32 7-Segment Display Interfacing. Set up a new project as usual with system clock @ 72MHz.

Introduction: 14 Segment 2 Digit LED Display

Story

Over the last several years I've tried to learn how electronic devices work, by this I mean how to get them to work with an Arduino or any controller device, this includes displays, sensors or anything else that returns a value of some sort. At the same time I am driven by my imagination to create purposeful projects I find interesting and usually outside the realm of normal. I have played with many displays, some of which I have learned to use and plenty of others I still struggle to gain a basic understanding of.

Display

One such device is the 14 segment LED display. At first glance I was confused by the number of pins on the back of the display, this is a two digit display with only 17 pins numbered 1 through 18. As I usually do I came to Instructables to seek out any projects this community has published, under various search criteria I found little on the very basic information I needed to get it to light up and only a couple of projects.

I've searched many other web sites as well but all were too advanced for what I needed to know. The other day I dragged out my collection of LED displays and decided to manually go through the pins one by one to see if I could get it to respond. I did then by the process of trial pin by pin map the configuration of the display. I have not yet looked into which driver chip will control the characters but I have found very basic pinout usage. Hope this instructable is helpful and useful to others.

I've written this instructable with beginners in mind but there may be a morsel or two for the more advanced maker. I never turn down the opportunity to read someone else's words, they will often ring a bell. YES I DO HEAR BELLS IN MY HEAD!

I'm including a number of documents from other sites in PDF form, most of it is quite technical but for pinout purposes they should get you up and running quickly. Seeed Studio sells the ones I have so I included their data sheets and some other information. Seeed Studio says these displays are compatible with Arduino and there are driver chips available for more advanced use.

14 Segment Display

Supplies

Step 1:

Step 2: Materials

5 volt power supply or an Arduino Uno, Mega or any other controller board with power out pins.

Medium sized bread board.

Segment

330 ohm resistors.

Jumper wires.

14 segment 2 digit display.

Step 3: Putting ItTogether

From your power source connect jumpers to the power bus on the bread board. The red line on the bread board is for positive (+) and the blue or black line is for the negative side (-). Connect these to the bus closest to the power supply then jumper the positive wire to the power bus on the other side of the board.

For test purposes insert a 330 ohm resistor from the + power bus to an unused set of pins closer to the ends of the board then connect a probe wire from the resistor. The probe can be moved to various segment pins. The ground wire (-) can be connected to pins 11 and/or 16. A ground to pin 16 will cause the segments in digit 1 to light as you touch the probe to them and pin 11 supplies ground to the segments of digit 2. The resistor is important for limiting the current through the segments, the value of the resistor is not critical but the higher the resistance the dimmer the LED segment will light.

Step 4:

Most of these displays are wired the same unless they are made for a particular product manufacturer.

Some displays have a reverse polarity where the 2 common pins (16 & 11) are positive (+) and the segment pins are negative (-). Just reverse the power supply connections.

The coloured image of the display has the segments identified by the lower case letters 'a' through 'm', Seeed Studio does not use the letter 'i', it looks too close to 'j',

therefore the letters to designate the segments are 'a' through 'n' skipping the letter 'I'.

The displays I have have no #3 pin but most others do, it was probably left out to cut the cost of manufacturing. Thats okay because pin 3 is not used, some other similar displays may have that pin for an additional feature.

The data sheets will give you all kinds of info you may need for a very specialized purpose, but no matter what colour the LEDs are the pinouts will be the same.

Step 5:

FINALLY

I hope this instructable helps, I purchased these displays a few years ago then didn't have time to devote mapping out the pins. Information is difficult to find and sift through, I like reading but not for hours chasing dead ends.

Enjoy and get creative. In a future instructable you will see my use for these displays.

I have included several PDF files for you to download that should help. Metal gear solid 2 pc download full version.

Attachments

  • This is 0.54%22 14 segment common cathode LED and the color is yellow….pdf
  • 14 segment with max6954 driver.pdf

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Answers to Questions (FAQ)

14 Segment Display

How does a 7 segment display work?

Basically, the display consists of seven segments identified by a letter (from a to g), organized as follows: 7-segment' loading='lazy' /> and each segment is generally associated with an LCD screen or a LED and can thus be activated / on 1 or off 0. There are a total of 128 possible combinations of display, although it is most often the combinations for the 10 digits (from 0 to 9) that are used.

How to encrypt with a 7 segment based cipher?

Segment combinations can represent characters. A combination is generally identified by a series of 1 to 7 letters (from a to g) corresponding to the activated segments.

It is also possible to identify them with a binary string 1 = active, 0 = inactive, starting from the end gfedcba. In this way a is 0000001 and g is 1000000

Example: has all active segments coded either abcdefg or 1111111

Example: has the 4 bottom segments active, coded either 'c, d, e, g' or 1011100

The 7-segments displays may be common cathode (CC) or common anode (CA), in this second case the 0 and 1 are switched.

How to decrypt a 7 segment cipher?

Associating an abcdefg code with a display consists of illuminating / activating the corresponding segments.

Example:abcdefg illuminates all segments and displays

Example:bcdeg illuminates segments b,c,d,e,g and displays

What is a common anode or common cathode display?

14 Segment Display Common Cathode

In a common cathode display, these are connected to the low potential, a segment is displayed by activating it in its logical 1 position.

In a common anode display, these are connected to the high potential, so a segment is displayed by activating it in its logical 0 position. Dhola ve kaali mar jawan gi mp3 download.

How to recognize a 7 segment ciphertext?

The code consists of the letters a,b,c,d,e,f,g only, in groups of 1 to 7 letters without repetition.

For the binary variant, the codes are normally on 7 bits from 0000000 to 1111111.

How to create a bootable usb for powerpc mac g3. The presence of a calculator, a clock or a digital watch or the characters 7SEG are clues.

What are the variants of the 7 segment display?

There exists also 9 segment displays (with an additional 2 segment diagonal), 14 segments (with 2 diagonals and a central vertical bar) or 16 segments (identical to the 14 segments but with the top and bottom segments cut in half).

The Beghilos code uses the 7 segments with a reverse reading (backwards).

Adafruit 14 Segment Display Tutorial

When 7 segment displays was invented?

The first patents date from the beginning of the 20th century (1903, 1908, 1910) but the advent of the displays came in the 1970s.

Source code

Display

dCode retains ownership of the online '7-Segment Display' tool source code. Except explicit open source licence (indicated CC / Creative Commons / free), any '7-Segment Display' algorithm, applet or snippet (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any '7-Segment Display' function (calculate, convert, solve, decrypt / encrypt, decipher / cipher, decode / encode, translate) written in any informatic language (Python, Java, PHP, C#, Javascript, Matlab, etc.) and no data download, script, copy-paste, or API access for '7-Segment Display' will be for free, same for offline use on PC, tablet, iPhone or Android ! dCode is free and online.

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