200 LED controller, individually selectable?

Discussion in 'The Projects Forum' started by stevefed, Aug 2, 2016.

  1. stevefed

    Thread Starter New Member

    Aug 2, 2016
    New member, long time electronics fan...not a complete noob; but...
    So I have a rock climbing wall in my house (don't ask...haha), and instead of using tape to mark the "route" I would like to use LEDs embedded in the plywood sheeting. For a smaller scale I might just use switches, but seeing as how the kids have hundreds of holds on the walls, I would like to start with a section of 200 laid out like the old battle ship game, 1-18 and A-K (not exactly 200 but seemed easier than 198). I have seen tons of LED projects, fading, chasing, blinking, etc. but have not quite found a design that utilizes a "controller" (I would like to use a keypad of some sort vs. dragging a laptop to flash code) to light up individual LEDs. I might need 7 or 8 lit up at once with the rest off; or if this is easy to some of you, might we try using RGB LEDs and lighting up a few "routes" with different colors? I have a little experience with coding and audrino/rasberry, plenty of time and budget of a few hundred bucks. can this be done? Much Appreciated! Man, I should have paid more attention in electronics class! Thank you in advance
  2. MrChips


    Oct 2, 2009
    Create a two-dimensional matrix of rows and columns.
    16 rows x 16 columns will give you 256 intersections. An LED is wired at each intersection between one row and one column.
    Use a microcontroller with two 16-bit output lines. The MCU scans rows and columns to select which LED is turned on. Scan at a fast enough speed and the LEDs will appear to be on constantly. Scan too slow and the LEDs will flicker. You want to access each LED at least 30 times per second to eliminate flicker.
  3. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    Last edited: Aug 3, 2016
  4. AnalogKid

    Distinguished Member

    Aug 1, 2013
    Something to note about a 16 x 16 array - that is an *electrical* array that describes the electrical connections. Physically, the LEDs can be placed anywhere on the wall. They do not have to form a 16x 16 grid when illuminated. And each intersection point between a row line and a column line is independent of all others; you do not have to populate every possible x-y location.

    atferrari likes this.
  5. stevefed

    Thread Starter New Member

    Aug 2, 2016
    thanks everyone, somehow I was stuck on the whole column/row thing, thinking it would light up the entire line at once and not the actual intersection of the row. I'll look into the neopixel - if they are not too spendy I would like the colored option. As for the array concept - that makes sense to me and I have a few sheets of plywood with random holes where perpendicular x/y won't work but nice to know they can still have an "intersection." Thanks! time to dig out the electronics box and wire up a small one.
  6. atferrari

    AAC Fanatic!

    Jan 6, 2004
    For a test, a 4x4 will do. Once you have grasped how it works, then go for the big one. More and longer wires and good oportunities of you confusing yourself! That's where the fun lies...