I have a working LED Moving Display Sign!

T&E Engineer

I finally have a working LED Moving Display Sign that·scrolls across 20 columns using (3) 4017 ICs and a 4081 Quad AND gate IC.

It runs much better on a BS2px but will run on a BS2. I will also in a later version convert it to run on a SX28 as the code is simple but effective.

The code was converted from a PIC program I saw on the Web. It does not use any array variables so that will not be an issue for a later conversion to the SX28. There is plenty of code space left over with variables.

I will post it now for those interested with a link to the designers original circuit / code.

http://drew.hickmans.net/movingsign.htm


Thanks,

Timothy Gilmore


Post Edited (tdg8934) : 12/9/2005 3:20:02 AM GMT

T&E Engineer

I have posted a picture of my 20 column LED display in the original post.

I have a 2 min. WMV movie (2 MB) but it causes an error·when I try to upload it. PM me if you would like to see it. The quality isn't great but you can get the idea. I had to slow down the display 10 times to see the letters somewhat clearer. At full speed, the letters are blured when trying to create a WMV.

I think I have it complete for now and will start to work on an SX28 conversion next.

Comments....sugestions...

Thanks,

Timothy Gilmore

Forrest

Looks good - I'm glad to hear the BS2P was fast enough to run the display. What type of power supply are you using to feed your display?

T&E Engineer

I'm using a standard 7.5vdc 1A wall transformer going into the Professional Development Board (PDB) as purchased·from Parallax. Although VDD is regualted at 5vdc going to the stamp and the rest of the circuit as shown on the schematics.

Although I do think the brightness is acceptable, it is a little dim. I have a 5vdc 2A wall transformer, that may make it brighter if I don't regulate it. Hmmm.

This will also run on a BS2 but it is·slightly slow for my taste but may be ok for most applications.

Thanks,

Timothy Gilmore

T&E Engineer

I have ported over a SX28 version of the LED Moving display sign.

http://forums.parallax.com/showthread.php?p=561515

Thanks,

Timothy Gilmore

deno

Hello...I have been following your LED display sign posts...I have been working with the LED 8x5 display modules for some time and I have build complete units (2) for use on my boat to display time on one and voltage on the other.

I found that the BS2sx is much faster and reduces the "flicker' of the display comparied to the plane old BS2.

The voltage display uses 5 LED modules to display the battery voltage, and the time/date display uses 4 LED modules.· I did play around with trying to scroll the display, much like you see in the stores when you buy a lottery ticket. However, I decided to just display the "whole" value.. i.e. 12.67v. Then display a compairson of voltage on the next page, then back to the voltage reading again.· The same with the time and date on the other display.· Anyway, I thought you might get some ideas from my code, as I did get a scrolling idea from yours...thanks

By the way, because I am multplexing the columes at a fast rate and·I was able to get away with using 10 ohm resistors in series with the LED's for current·limiting with no burn out as of yet. This got my brightness up for viewing.

Deno


Post Edited (deno) : 12/8/2005 3:08:25 PM GMT

T&E Engineer

deno,

The code looks really good. I will examine it closer. I like how you have used a DS1302 as I was thinking of adding the time to my LED Moving display. What I really like is to hear that you moved to 10 ohm resistors for increased brightness. Are your resistors on the rows (8) or columns (5)*4?

In my·design it uses 100 ohm·going from transistor·power amplifiers into the rows. I would certainly like to change them out to get a bit better brightness. ·I tried changing to a 2 A power supply from a 1 A one and noticed no additional current draw either so lowering the resistors would be the next step.

Great work!

Thanks for posting your code.

Timothy Gilmore

deno

Hello again...the rows have the 10 ohms resistors.· Sometimes when I download a program change to the stamp, a colume of LED's will freeze "ON" while the program download takes place, but this is only for a couple of seconds or so, and I was nervous at first of burning something up, but so far so go.· This "freeze" only happens once in a while...so I don't really worry about it.

Deno

LoopyByteloose

You did an excellent job!

and you have got me thinking about a 16X16 grid to display Chinese characters one at a time.

I suppose you could disconect the LED power while programing.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

T&E Engineer

deno,

I changed the 100 ohm resistors going to the 7 rows to 10 ohm. I noticed a bit more brightness. However, I don't want to remove·them all together. It appears to be working fine.

I have also updated the code and hardware info for Altitudeap (custom project I did for him tonight) in the SX section that you may want to look at.

http://forums.parallax.com/showthread.php?p=561515

Thanks,

Timothy Gilmore




Post Edited (tdg8934) : 12/9/2005 3:21:08 AM GMT

dazed&confused

If you like the BS2 then you will really like the BS2P/BS2P40. Trust Me on this one, If your into $Basic, Like I am, You'll love the the Newer Chip!!!!__Much faster__More code.....Also see VER. 2.4 Editor DownLoad..

Lab Rat

i have found some resources for using an 8 bit shift register instead of the decade counter i think if it turns out right i can modify pre-existing programs that are demonstrated in the stamp works manual.
me being the fool i am i now have 70 LEDs oriented in the wrong polarity for the IC that i am using so i now have to put in 7 NPN transistors to get things back on track. i figured out that i screwed up when i was sitting in study hall and trying to figure out how to program it. since i was not about to dig out a soldering iron in the middle of studyhall i decided to try out the 74LS164 (8 bit shift register) that i was using. for those who ask where i pull parts from at school i have a few necessary parts and what not in a box with me that i carry from home to school it is my graduation project. well any how i set up the 74LS164 on my homework board plugged in a few LEDs and amused a few freshmen (how stupid they are) (REMEMBER i am only a senior in high school not trying to offend college freshmen) i must admit i amused myself too lol