Searching \ for '[EE]: Part reducement' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=part+reducement
Search entire site for: 'Part reducement'.

Exact match. Not showing close matches.
PICList Thread
'[EE]: Part reducement'
2002\05\17@141716 by Dennis Noordsij

flavicon
face
Hi,

I am making a few PCB's containing 4 7 segment LED displays, which are daisy chaised through 74HC164 shift registers, using 2 pins on a PIC to drive them all.

This all works fine, but for each PCB I currently use 2 shift register IC's (for a total of 16 output pins, 4 per 7 segment display), and for each 7 segment display a 74LS249 BCD-to-7segment decoder IC, which have open collector outputs so add one resistor per segment (total of 28 + 1 dp per PCB), for which I can of course use compact housings containing several resistors in one.

This adds up to 6 IC's and 29 resistors per PCB. i.e. over 150 holes to drill :)

I am wondering if anyone knows a more compact version, i.e. less parts. The price of this setup is fine, but simpler is usually better.

I have looked for 3 1/2 -in-one segment displays, but couldn't find any around here, so I can't rely on some obscure all-in-one unit. I can source most "regular" IC's here, so I'll build it from seperate 7 segment displays (common kathode). Any suggestions? Such as BCD convertors with more outputs, larger shift registers with enough grunt to drive the segment LED's? etc?

Regards,
Dennis

PS - I can use an LCD, but for this particular application I prefer the big bright easy-to-read-also-from-a-distance LED displays.

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\05\17@142811 by tundra

flavicon
face
Dennis Noordsij wrote:
>
> Hi,
>
> I am making a few PCB's containing 4 7 segment LED displays, which are daisy
> chaised through 74HC164 shift registers, using 2 pins on a PIC to drive them
> all.
>

<SNIP>

I have already completed such a project which can handle up to 8 LEDs.
The project can be found at:

  http://www.tundraware.com/Software/PIC/leddrvr2/

The zip file includes a PCB layout in Eagle format which I had Olimex
make for me.  The board is designed to fit twice on standard Olimex
proto panel, so you get 2 boards for about $40 US.

My design only requires one SIP resistor termination pack and two additional
pullup resistors.  The total parts count is pretty small - not counting the
LEDs themselves, it requires someting on the order of 25 components including
the PIC.

The hole count is high because the LEDs alone account for 112 (8 x 14).
I was going to make the PCB myself as a single-sided board, but it is not
practical for this kind of project, IMO.  You can see the finished board at:

  www.tundraware.com/Software/PIC/leddrvr2/leddrvr2-board.jpg
------------------------------------------------------------------------------
Tim Daneliuk
spam_OUTtundraTakeThisOuTspamtundraware.com

--
http://www.piclist.com hint: PICList Posts must start with ONE topic:
[PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads


2002\05\19@185624 by Bob Blick

face picon face
Why don't you matrix them?

-Bob


{Quote hidden}

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.


2002\05\20@025308 by Mircea Chiriciuc

flavicon
face
U can use HC595 shift registers to drive the display. So you will need only
4 IC's. The resistors have to stay for current limitting, but you can use
SMD resistors so U will have 86 holles less to drill.  ;)

Mircea Chiriciuc
EMCO INVEST


{Original Message removed}

2002\05\20@160144 by Harold M Hallikainen

picon face
       Have a look at http://www.allegromicro.com/sf/6276/ . This is a 16 bit
constant current LED driver. Two of these chips could drive your 4 digits
with no current limit resistors, etc. You'd do the bcd to 7 segment in
software.

Harold

On Mon, 27 May 2002 19:42:05 +0300 Dennis Noordsij
<.....dennis.noordsijKILLspamspam@spam@WIRAL.COM> writes:
{Quote hidden}

FCC Rules Online at http://hallikainen.com/FccRules
Lighting control for theatre and television at http://www.dovesystems.com


________________________________________________________________
GET INTERNET ACCESS FROM JUNO!
Juno offers FREE or PREMIUM Internet access for less!
Join Juno today!  For your FREE software, visit:
dl.http://www.juno.com/get/web/.

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listservspamKILLspammitvma.mit.edu with SET PICList DIGEST in the body


More... (looser matching)
- Last day of these posts
- In 2002 , 2003 only
- Today
- New search...