Shop OBEX P1 Docs P2 Docs Learn Events
LED moving display questions — Parallax Forums

LED moving display questions

T&E EngineerT&E Engineer Posts: 1,396
edited 2005-10-05 13:28 in BASIC Stamp
I am new to the BASIC stamp and have a .BS2 version that came with my BOE-BOT. I am using mainly the Educational Board for experiments with the BASIC stamp.

I have always wanted to build an LED·moving display sign and I tried a few years ago with IC's and transistors, etc.. but never got it to work right.

Does anyone have any information on designing a LED moving display sign using the BASIC Stamp BS2?

I currently have made an array using 20 (columns) x 7 (rows)·red LEDs 10mA each (or think of it as 4 * (5x7) LED sections). I saw some other similar designs using 5 x 7 displays which I could not find easily so I made a large array myself using some perf board and lots of LEDs.

What size resistors to use? I am thinking of 100 ohms across each of the 20 columns.

Any help would be greatly appreaciated so I don't have to re-invent the wheel if it is already done. I have seached Google and some Stamp sites and found bits and pieces which certainly may help but not provide the big picture in it's entirety.

Thanks,

Tim···· turn.gif

Comments

  • Jon WilliamsJon Williams Posts: 6,491
    edited 2005-10-04 22:35
    You'll need a display multiplexer like the MAX7218 (which will do an 8x8 array, so stacking three will give you 24 x 8). Still, that's a lot of memory to manage and unless you were just going to send fixed information out of an EEPROM table, you'd need a BS2e or higher to get Scratchpad RAM that you could use to store and manipulate your column data.

    Warning -- this is NOT a beginner's project.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Jon Williams
    Applications Engineer, Parallax
  • Sun1ShineSun1Shine Posts: 10
    edited 2005-10-05 13:28
    Cheap and cheerful quick scrolling LED display can be created by using a LED display badge (they are normally powered by a cr2032 battery), one programmed by a serial port, and then outputting text to it via the BOE or WAM serial port. I have already done this with my WAM (Homework board). This is $20 or so and only requires your serial port and the correct sequence of control characters to the badge. I have a brand new case of these and could provide one (plus cables batteries and software) if you are interested.
Sign In or Register to comment.