504 Cue PC Controlled Efire panel
Original build based on design by Joe Zastrow
PC Control adaptation by Larry Embrey
PC Fire upgrade
New case (~$85)
USB 2 DMX cable (~$100)
DMX Converter (~$300)
50 Micro Relays (~$50?)
2 Breadboards ($3.99/ea radioshack
I considered quite a few formats for this migration to PC Controlled firing. Each had it's pro's & con's.
I considered; DIY parallel port X-mas light system, Midi, and DMX.
The X-mas light package showed great promise, but the labor involved setting it up and having to create software were a big drawback.
Midi also looked good, It already have built in ability to tie to music timecodes so synching would be straightforward, there were some off the shelf analog output devices, but support was lacking.
I eventually settled on DMX as it is an the most common format for light show production sequenced to music. Pretty much any concert you see, or DJ at a party is using DMX for his lighting and effects. Another added bonus is that there are already premade pieces of equipment that will output multiple channels of 0-15V output, no need to create complex circuits from scratch.
There are also off the shelf software packages to allow setting what channel to activate based off timecodes in music output from windows mediaplayer, winamp, etc. Another huge help is that my shooting partner already has DMX built into his DJ cart that we use for music output during our shows. I resisted DMX for a long time as it's one BIG drawback is cost. It is the most expensive of the 3 formats I considered.
The concept behind this upgrade is fairly straightforward, since I already had a running system and just wanted to add PC Control. I was originally going to rewire most of the system and build it so that my existing buttons or the DMX system would trigger the relays.
The relays would always carry the 24V system load, whether I was manual fire or PC controlled. Not only was this overly complex, but I had issues with potential mixing of voltage sources and much higher ampload on the batteries in manual mode to trigger the relays. So I stepped back and realized I could build it so the PC controlled relays piggy-backed the buttons as drawn below. This will save HUGE amounts of time and effort during this build up.
Integrating PC fire brings up a number of issues, especially safety. I will be integrating multiple safetys in the system to make sure there are no accidents during show set-up, continuity checks, etc. I already have a 2 key system for putting the system in fire mode, one for system power and another for allowing power to the buttons to fire. In test mode the only power going into the system is thru the continuity LED's, the buttons have NO power at all. I will be keeping that system and adding a 3rd key to select between manual fire and PC fire. Ontop of that I am going to incorporate some sort of deadmans switch. I am currently looking at a tether system like used on Personal recreation craft, move away from the panel, fall etc and off goes
shoot power.
I am doing this as we typically shoot 15min+ shows and I don't want to get finger cramp holding down a button the entire show, but I want a safety you don't have to think about to engage, so if I get hurt and fall it will stop shooting.
Another feature I am adding based on Joe's schematics is built in batteries with external charging. I will add pictures of the schematic later. As you can see I am adding a ton to the system, which is why I am going to the bigger case.
I am most likely also going to add a voltmeter so I can monitor he individual
batteries for charging as well as system voltage during a show.
Enough
blabbering for now.. on with the pictures..
