Scrolling LED Stock Ticker - Page 1
Forum section: electronics / beginners

author: gohangasalamimalasagnahog
author_rank: Newbie
timestamp: January 15, 2012, 01:51:38 am
content: I had an idea a while back to make my own stock ticker. I posted about the potential topic here, but I abandoned that approach a while ago and forgot about the project until very recently because I got some parts and some time off to work on it. Still need some help with it though, so i'm posting this.The original thread if you're interested is here:https://www.eevblog.com/forum/index.php?topic=3690.0The project as it is now:I plan on making a bi-color (red/green) display that is 8 x 80this display will be controlled by an arduino running 10 shift registers driving the columns and 2 more shift registers sinking the rows.the arduino will also be connected to my computer which is constantly scraping up-to-date data and pushing it to the arduino.Details:I got a bunch of 8x8 red/green common-anode matrices. I will be using 10 of these chained together to form the display.12 74HC595 shift registers will be daisy-chained with the first 2 being used to sink the 16 rows (8 red, 8 green) via N-MOSFETs and the other 10 driving the 80 columns directly.I have already written some code to run on my computer to scrape yahoo finance for stock prices. It creates a matrix of 0s and 1s that represents which LEDs should be on (1) or off (0)This matrix is then pushed to the arduino which will drive the shift registers.i found a simple 8 pixel high font to use. hopefully the display will look something like this when done:My first hurdle is figuring out how to feed the matrix of 1s and 0s into the shift registers.If i have a matrix that says "HELLO":{{1,0,0,1,0,1,1,1,1,0,1,0,0,0,0,1,0,0,0,0,0,1,1,0},{1,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,1,1,1,0,1,1,1,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,0,0,1,0,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,0,0,1},{1,0,0,1,0,1,1,1,1,0,1,1,1,1,0,1,1,1,1,0,0,1,1,0}};how would i feed a line into 3 shift registers?i have only seen how to shift in 1 byte at a time in hex or decimal.using the second row as an example:I am assuming i would still have to do this one byte at a time? feeding in first the 8 bits in red, then the yellow, then the green?is there an easier way to do this? and how do i send them to the shift register without first having to create a decimal value representing each byte?I thought using an arduino for this would make it much easier, but i still can't find an easy solution.Any other advice, help, or feedback would be greatly appreciated.

author: Gridstop
author_rank: Contributor
timestamp: January 15, 2012, 03:11:11 am
content: What I found when I made my LED marquee was it was easier in terms of PCB layout to do individual 8x8 sections and multiplex across the columns rather than rows, where each PCB multiplexes separately. A single uC acts as shift reg & multiplexes the LEDs. Again, it was simpler in terms of PCB layout to use discrete transistors to drive the cathodes. Of course, if you really need two colors, it will get more complex.

author: rjcahoy
author_rank: Newbie
timestamp: June 28, 2015, 02:27:40 pm
content: Curious if you ever finished creating your ticker?We build commercial versions (www.risedisplay.com) but I have been seeing a lot of activity for the DIY community to build them for man caves.The way we do it is we use a linux device to render a bitmap image that sends it to a controller created by Sunrise (www.sunrisesystems.com) that just shifts it down the line for an infinite length.Interested to see what the DIY community is looking for and if there are any kits or things we could create to help.