LED Display - Questions!
GeorgeG
Posts: 5
Hi there,
I'm planning to build a "simple" LED Display, although I have some questions that need to be answered.
First of all, I'm gonna use 64 (red, or maybe blue) LEDs.
PLAN 1:
Use one 74HC164(N) to control 8 74HC374(E) that control 8 LEDs each.
PLAN 2:
Use another "controller" (74HC164) that has more outputs (more than 8, maybe 64 if that exists )
Whats your opinion, or what else can I do?
Thanks in advance!
I'm planning to build a "simple" LED Display, although I have some questions that need to be answered.
First of all, I'm gonna use 64 (red, or maybe blue) LEDs.
PLAN 1:
Use one 74HC164(N) to control 8 74HC374(E) that control 8 LEDs each.
PLAN 2:
Use another "controller" (74HC164) that has more outputs (more than 8, maybe 64 if that exists )
Whats your opinion, or what else can I do?
Thanks in advance!
Comments
Maybe a MOD can move it please? [noparse]:([/noparse]
Not sure where you intended to post this message since it makes no mention of a BASIC Stamp, SX or Propeller microcontroller. The ‘controller’ you mention is actually a parallel to serial shift register. It’s unclear from your post how you plan to interconnect these device. 64 LEDs can easily be controller (including brightness) from a single MAX7219 IC or an array of 74HC595 chips (without brightness control).
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support
Im gonna make the Display show different things.. [noparse];)[/noparse]
There are several Nuts and Volts columns on Parallax's website that demonstrate the use of various
I/O extenders with Stamps. They're all downloadable. The StampWorks manual is also downloadable
and has a section on the use of the 74HC595.
www.parallax.com/Resources/NutsVoltsColumns/tabid/272/Default.aspx
www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/txtSearch/stampworks/List/1/ProductID/144/Default.aspx?SortField=ProductName%2cProductName
http://forums.parallax.com/showthread.php?p=696682
It was built for the Propeller, but that is of little importance, as the program can be adapted to any processor
and thought this would be a great project. If not I will put it on the back burner until I am able better understand the spin code myself.
Thanks,
Al
Charlieplexing arranges the LEDs in a way so you can also set a column (-) and a row (+),
reducing the number of needed pins from - say - 8+8=16 for 64 LEDs to 9 (which would even cover 72 LEDs)
The drawback is that it is quite tricky to use current amplifiers, as they have to have three states.
The Propeller has the advantages that ALL its pins can - in principle - source and sink 50 mA which is fine
for multiplexing 64 superbright LEDs without any resistors (and even exceptable for standard LEDs...)
And "scrolling text" is a program of its own of course...
http://forums.parallax.com/showthread.php?p=684565