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View Full Version : PJ Link implementation



gazzer82
28-08-2008, 12:48 PM
I currently have to provide two CAT5 connections at each projector, one for the projectors web control interface and one for an IP Serial Box to control the internal shutters.

What would be great would be PJ Link built into Catalyst so i can control the internal shutters of the projectors via the same CAT5 network connection i use to access the internal web interface, thus removing the need for two cables and also the IP Serial Box.

I'm sure it's pretty low down on the list but Richard if you get a chance . . .

Cheers

Gareth

SourceChild
28-08-2008, 01:11 PM
Gareth,

You should be able to use the same Cat5 wire. As long as the protocol used on the serial box is TCP/IP you can connect the two of them. Each device can be assigned to a different subnet if you require separation. However, you shouldn't really need to separate the nodes.

One issue you'll face is the ability to run both devices. Ethernet does not daisy chain. You would still be required to have a switch (technically just a hub would be fine) at the projector to send a signal to each node. I'm inclined to believe that the extra ethernet cable is worth more than the extra switch in terms of cost savings and reliability.

gazzer82
28-08-2008, 01:24 PM
Thanks for that, yes that is what i do at the moment, if i have a situation where i have several projectors at one location i will use a switch at that end and feed all devices from that, or if it is a single projector then i will send two Cat5 from the switch at the rack end, but it still means i need the IP serial boxes to make it work, and also additional network switches which are all things to go wrong/break. I am a big fan of making things as simple as possible.

I have managed to kind of do this with catalys as it is using applescript to open a telnet session to the projector (which is all PJ Link is as far as i can tell) and send the various commands that way, but it takes a little while for the session to become active before you can send commands, so not very suitable for swift shutter commands. I guess i could be a little bit intelligent and write something in X-Code that will respond to applescript that keeps the session open and sends the commands, but it's another thing to go wrong!!

Cheers

Gareth

SourceChild
28-08-2008, 01:35 PM
Honestly, if you're familiar with Xcode try writing a simple serial command stack that you can run as a dynamic shell script. Use Applescript to initiate the shell script commands to do the following commands:
Open Shutter
Close Shutter
Power On
Power Off
etc.

Basically, just write your own serial interface for projector control and that way you can have a single serial device running both and you don't have to use the clunky slow ass web interface for the projectors.

In fact, if you're any good with interface builder, write an application with buttons on it which perform projector operations and then link operations to Triggerable events for SAMSC-Lite to run.

gazzer82
28-08-2008, 01:52 PM
Yeah i wouldn't say i am an expert, but i can put a basic application together, and i also have a fair bit of experience with interface builder. You've challenged me now to try and do this, and in fact having a GUI where you could choose a projector to control, and also query the current status would be quite handy. So i think i will see what i can do, standby for a very very rough alpha in the hopefully not to distant future.

Would this be of any use to anyone else?

Cheers

Gareth

SourceChild
28-08-2008, 02:08 PM
Yeah,

I wouldn't say I'm an expert in Xcode (yet). I have however spent the last six months learning it a whole hell of a lot better. It's amazing the things you consider when you know how the code works.

Just wait til you see the new control console I'm working on. I'll give you a hint... Think Multitouch and a 24" 1920x1200 version of the iPhone type control interface.