Pages: [1]   Go Down
Author Topic: 4 Digit 7 Segment, Colon & Decimal points  (Read 2279 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I am looking for either a high bright LED or a backlit LCD where I can use all the DP and Colons.  Many of the components out there you can either use the colon, or the DP, but not both.  I am baffled why the manufacturers would do this.

Can anyway suggest a component and a suitable driver?
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

O, and it should be a 14.22mm(0.56") size if LED and/or a similar size LCD...
Logged

Western New York, USA
Offline Offline
Faraday Member
**
Karma: 40
Posts: 4411
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
Many of the components out there you can either use the colon, or the DP, but not both.  I am baffled why the manufacturers would do this.
Here's my guess, it's pure speculation.

If you look at the pin layout for a typical single 7-segment LED you will find out that it has 10 pins.  Since they use two of them for the common connection and seven more for the segments that leaves only one free pin for either a decimal point or a colon.

Why do they need two common connections and why don't they replace one of them with the missing colon (or decimal point) you ask?  That's because the pinout is arranged so that the device can be plugged in upside-down and the seven segments will still function as intended due to the symmetry in the pin layout.

Why do you want this symmetry?  Because if your display is equipped with a decimal point you can use two of the devices, side by side, with one of them upside down and the two decimal points will now look somewhat like a colon!


Don
Logged

Cardiff, UK
Offline Offline
Jr. Member
**
Karma: 0
Posts: 73
Programmer of all sorts
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I purchased a 4 digit LCD from Farnell and that had separate colon and decimal point control.  It didn't have a backlight though.

If you download my LCD/LED library you'll find the datasheet for the LCD I used.  I used an AY0438 display driver.

http://code.google.com/p/arduino-seven-segment/
Logged

My Arduino 7 segment LCD/LED library

http://code.google.com/p/arduino-seven-segment/

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 548
Posts: 27387
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Wow, I had never really looked at that before.
I just looked thru the 0.56" 4x7 LED displays at kingsbright and none of appear to breakout both decimal points and colons, it's one set or the other.
http://www.kingbrightusa.com/category.asp?catalog%5Fname=LED&category%5Fname=KC4%2DDigit+0%2E56in&Page=1
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

@floresta - that is fine, but I want a 4 digit display, with all the DP(4) and a colon. 
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

@floresta - that is fine, but I want a 4 digit display, with all the DP(4) and a colon. 

Ah, sorry, I misunderstood you.  Sure, 2 4-digits side by side.  Anway, there are displays that does this, Sparkfun has them, but is just too small.
Logged

Central MN, USA
Offline Offline
Tesla Member
***
Karma: 75
Posts: 7272
Phi_prompt, phi_interfaces, phi-2 shields, phi-panels
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

deaurgtehne,

I was on the same quest but failed to find anything online. Kingbring doesn't have them, as CrossRoads pointed out already. They have lots but just not what we are looking for. Sparkfun has LED display with both colon and decimal points in a few different colors but too small. I was also looking for 0.56" digits. I have a display sample from an ebay seller but the DP are not connected despite the fact the photographed spec sheet says they are. I'm done looking but if you find any sources, let me know. I have a hunch that industry doesn't need both, they need PD or colon for each application but not both so there's no need to drive the shops to make both. But sparkfun is a different story. They slap a lot of "red flames" on generic parts and sell for high profits so they are very convincing when they talk with shops that make these parts.
Logged


Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

deaurgtehne,

I was on the same quest but failed to find anything online. Kingbring doesn't have them, as CrossRoads pointed out already. They have lots but just not what we are looking for. Sparkfun has LED display with both colon and decimal points in a few different colors but too small. I was also looking for 0.56" digits. I have a display sample from an ebay seller but the DP are not connected despite the fact the photographed spec sheet says they are. I'm done looking but if you find any sources, let me know. I have a hunch that industry doesn't need both, they need PD or colon for each application but not both so there's no need to drive the shops to make both. But sparkfun is a different story. They slap a lot of "red flames" on generic parts and sell for high profits so they are very convincing when they talk with shops that make these parts.

so... what do you want to do with these? As it seems like we are the only ones with the need for it! PM me. Cheers!
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 20
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I am going to be forced to useing Graphical LCDs, but they have a problem lasting in direct sunlight(and my application is focussed on 50% daylight exposure)....
Logged

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 548
Posts: 27387
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

So instead of 4 digits, can you use 2 two-digit displays and put your own colon in?
Or perhaps make your own panel up with 4 digits and 2 LEDs for the colon.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Anaheim CA.
Offline Offline
Faraday Member
**
Karma: 47
Posts: 2930
...
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

If you do some searching you might find your part, Surplus... I have one that almost fills your bill completely... Has 3 sets of colons,Dp's, it is a .3" display, 4 Digit 7 Seg Green display... I have 23 or 24 of them... Matsushita LN543GKN8, There were MANY different types of clock and clock/multifunction displays made. There were a lot of VFD types made as well specifically for clocks some were 7 seg and some were similar to nixies as they had an element for each numeral. That any of them are still being manufactured is still another question. They were at one time quite common and might well be found surplus. Diallight made a dual stacked led indicator that would have been perfect as a colon display and I am reasonably sure that in the DL76XX series of .56 displays there was a colon display as well as a '+/- 1' I have some of those too. The DL76xx series (at least the ones I have, 48 pcs red) are .56 7 seg red displays. I bought about 200 misc displays from Ebay for 10 - $20.00. So much for old history. I do hope my maundering was of help.

Doc
Logged

--> WA7EMS <--
“The solution of every problem is another problem.” -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Pages: [1]   Go Up
Jump to: