Hacking the HC-8+ in Hollywood

[JonnyMac]

Most of you know that the movie and TV business is important to me; I'm an actor (even in SAG/AFTRA) and love everything about movies and TV (okay, most "reality" TV I could do without).

One of the clients I get to work with is Alliance Studio -- a collaboration between Steve Wang and Eddie Yang.

With the proliferation of CGI, practical effects have been minimized in films (which is sad, really). In an interesting twist, the folks at Alliance have been putting their considerable skills into building displays for the gaming (all CGI) industry -- and they work with some big hitters: companies like Blizzard and Riot.

While I can't show you photos of the current project until it goes public, I can show you the control panel and some thoughts on programming. This display uses three HC-8+s, but they're really treated as two controllers. If you look carefully, you'll see an RS-485 link between the top and middle controllers. The top controller runs 16 outputs by using the middle controller as a DMX slave (no reprogramming required -- just moved the SM switch to the middle position and set the DMX address to 9 [%0_0000_1001]).

Inside that controller I have this simple method that lets it behave like it has more than eight channels:

pub set_level(ch, level)

  if (ch < 8)
    leds.set(ch, level)

  dmx.set(ch+1, level)

Yes, this is ridiculously simple, yet very powerful. The mainline code doesn't care where the output is physically connected, it simply calls set_level() and the details are handled there. If the output is local to the main control (ch less than 8), it sets the level for that channel. After that it sends the value via DMX. Note that channels in the program are 0..N, where DMX channels are 1..512 -- this is why there is the +1 in the dmx.set() method.

I could, of course, extend this to even more channels. The reason I didn't for this project is that for the amount of animation (not complex, but a lot of it), I was sure I'd need more than eight total cogs. The lower controller handles a focal element of the display, so it made good sense to isolate. We've only done the preliminary programming for a client review; we'll finalize it tomorrow so that it can ship to a convention. As soon as the display goes public, I will put pictures in the Completed Projects section.

For those of you that haven't seen what I've done with the HC-8+ here in Hollywood, check these threads:

-- http://www.efx-tek.com/php/smf/index.php?topic=2132.0
-- http://www.efx-tek.com/php/smf/index.php?topic=2023.0
-- http://www.efx-tek.com/php/smf/index.php?topic=1943.0

On the other side of the country, John B worked with our friends at Waverly Hills (Louisville, KY) to create a light tunnel using five HC-8+s controlling 18 strings of WS2801 (smart) RGB LEDs -- thousands of individual LEDs. In this case, the slave controllers used DMX but not just for levels; all of the controllers had a custom animation engine that would accept color and animation commands through the DMX stream.

I hope I can inspire more of our customers to hack the HC-8+ -- it's fun!