DIY DMX Splitter Schematic

[ddproduction]

I've come across a simple schematic for a dirt cheap DMX splitter/isolator, just wondering if anyone might have tried building this before, and/or have any comments? Also any comments on grounding the input and outputs?

 

http://www1.subether.net/~mike/DMX-Splitter.jpg

[david.elsbury]

This thread of mine from a few years ago may be of interest:

 

http://www.blue-room.org.uk/index.php?showtopic=22960

Also, your link appears to be broken?

 

David

[dbuckley]

Link works for me :)

 

Whereas that schematic arrangement looks like it would work, it has a fugly input arrangement tha will seriously load the incoming DMX line, so I would not recommend it. To do the isolation bit requires separate power supplies for both the input and output side, and for multiple outputs, for each output (or group of isolated outputs). The common Chinese-built eight way opto-iso has five mains transformers in the box!

[timsabre]

It is not what you'd normally call an isolated splitter, which would have every output isolated from each other. And as dbuckley says the input design is poor. However if you only want one isolated output and you don't have a lot of other devices on the DMX line it will work.

[matt c]

As an electronic engineer, that looks horrible! But as Mr Buckley implied, it would probably work, but I wouldn't use it.

 

I'm starting to think I should set up a small business making little widgets like DMX splitters.

[Tom Baldwin]

If you do try to build it, there appears to be a minor typo in the regulator part number - should almost certainly be 7805, not 7508.

[ddproduction]

I noticed that one! If I get bored, I might see if I can make any improvements and build one for the sheer affordability, and report back.

[timsabre]

I'm starting to think I should set up a small business making little widgets like DMX splitters.

I can save you some trouble here because I have got a small business like this and little widgets do not make much money unless you can sell loads... And DMX equipment is too specialised to sell loads.

[ddproduction]

Perhaps an opportunity for a BlueSplit project?

[timsabre]

Best way to do it would be with a 75176 on the input, then optoisolators to multiple 75176s on the outputs. Power these with NMA0505 isolated power supply modules for each output. At a fiver a go these aren't cheap though.

[Mystic]

I remember doing the calculation some years ago of the price of the components and plugs (5pins aren't cheap), and it was clearly a better bargain to buy a cheap chinese one than to make it, not counting hours of work (cheapo DMX splitter at thomann).

[Nicktaylor]

Parts probably at least £20. Time spent who knows? It might work. Best to just buy one second hand IMO! Or this one new!

 

http://www.thomann.de/gb/stairville_dmx_splitter_4.htm

[the kid]

I remember doing the calculation some years ago of the price of the components and plugs (5pins aren't cheap), and it was clearly a better bargain to buy a cheap chinese one than to make it, not counting hours of work (cheapo DMX splitter at thomann).

 

I might be wrong in remembering but that 4 way is actually 8 way, both the 3 and 5 pins on each out will work as out at the same time.

[Nicktaylor]

the kid

 

I remember that discussion. It sort of came down to the fact those sockets are physical parallels without isolation. It might work or you might get a signal bouncing back and corrupting the stuff on its parallel. I guess it depends on how mission critical the differnt DMX runs are?

[timsabre]

I remember doing the calculation some years ago of the price of the components and plugs (5pins aren't cheap), and it was clearly a better bargain to buy a cheap chinese one than to make it, not counting hours of work (cheapo DMX splitter at thomann).

 

I might be wrong in remembering but that 4 way is actually 8 way, both the 3 and 5 pins on each out will work as out at the same time.

 

yes, but they are not isolated from each other if that is important

It is true that even without including a cost for build time, it would be hard to build one yourself for that price.