Tuesday, April 14, 2009

Classic LED 7-Segment Displays

Just recently I have been addicted to old LED displays as they are small and bright and I love the classic look. We can see them in vintage calculators and vintage led watches. However these displays consume significant amount of power, so they are not used in watches and calculators anymore. As they are replaced by LCD, these LED 7-Segment displays are not in production anymore and difficult to obtain.

Now, I have 2 models of the classic LED 7-Segment as shown in the picture below: HP 5082-7414 from HP is on the left. It’s a 4-digit Red LED 7-Segment very nice for wristwatch. The one on the right is an 2-digit Red LED 7-Segment from an unknown maker. It can be used in a wristwatch too (with a little bit bigger case).

LED 7-Segment Display HP 5082-7414

Based on my inspection, I have made symbols for these displays with Eagle 5.4.0 free version. The displays are common cathode and the symbols are below

LED 7-Segment Display HP 5082-7414 schematic

The PCB footprints are as the following (DIP 12)

LED 7-Segment Display HP 5082-7414 PCB footprint

I have made simple clocks using these displays and PIC16F887. The real thing looks much better than the photo. The displays are bright red and sun light viewable. Very COOL!!! They are on my computer desk and I love to see them very often.
bubble-7-segment-clock

LED 7-Segment Display HP 5082-7414 clock

LED 7-Segment Display HP 5082-7414 digital clock

Each clock consumes about 0.25W (50mA, 5V) when the PIC16F887 operates at 250kHz (display refresh rate is about 61Hz). The amount of consumed current can be reduced significantly if I use some current limit resistors. But the displays will be dimmer than without resistors. I will try to use PWM for reducing the power consumption as I don’t want to put 8 resistors into my design. The schematic/PCB and firmware including source code in MikroC will be made public once I have complete all of the designs. I will even have kits for sell if my time permitted.

16 comments:

PIC said...

very classic

azila said...

Hi.. I'm a beginner to PIC. Actually I'm doing a semestral project on digital thermometer using PIC16F877. I want to use 3 digit 7 segment as display unit. Could you please help me on the source code and also the schematic as well? I'm really appreaciate your help. you can email me at azila_shoib@yahoo.com

RicardoATB said...

Hi,

I've been reading your articles lately and I give you "thumbs up" for your accomplishments!

Nowadays, I'm building my first 7-segment clock with PIC16F628A. As soon it start works I can send you a photo of my breadboard.

Hugs

Chuck said...

Hi
I'm trying to make a 4-digit Red LED 7-Segment display clock for my car. Could you PLEASE send me the schematic & source code for the clock you have on this site. Can I use the pic16f628A IC?
You can email me at sbcm07@hotmail.com
Thanks
Chuck

chamitesh said...

excuse me please send circuit diagram for "clssic led 7-segment diplays"
my emailid is ch.amitesh@gmail.com

chamitesh said...

kindly send circuit diagram for the project:"Classic LED 7-Segment Displays"

silent said...

please send the somplete pjct if u dun mind,i need it...:(
email:- ahmed_rohaan@yahoo.com

QwiateQ said...

Hi,

could you send eagle library with hp display and maybe code for operate it. I would be very helpful. Please send at qwiateq(at)os.pl.

Thanks.

Edsel da Silva said...

Hello, nice project, would you send the source code and the schematic please. edsel_187@hotmail.com

wlemi73 said...
This comment has been removed by the author.
wlemi73 said...

Hello, could you please send me diagram for Classic LED 7-Segment Displays. I will be use led HP 5082-7414. Thank you in advance.
My email mirek.lebiedzinski@goldi.pl

kbibi said...

hello can you send to me the source code and the shema for pic 16F877A or pic 16F84 and thank
kbibi99@yahoo.fr

Melvin Steele said...

Hey,
I need the Eagle Library, I would appreciate if you send it to me.
Thanks for your help!

Best wishes
Melvin Steele
(melvin.ste@gmail.com)

bobricius said...

Hi, great job, can you send my eagle library for this displays? Thanks. Peter.
bobricius@gmail.com

joel absalon said...

hello ilike you porject. please send circuit diagram in this email joel_absalon23yahoo.com. thank you. :)

szebee said...

Hello!

I like this watch! Congrats! Could you please send me the schematic & source code to email adress? szebeecrx@gmail.com

Thak you!

Kind regards,
szebee