Well, just an introduction. The DMX is a numeric protocol used lighting on stage control. You can find information here

So, when you have a lot of lighting or if you have long cables, you should use repeater. It’s also important as if you have an old calble, you may loose the communication during the show. I also use an isolator to separate the DMX network from the computer. But, I need a new small case splitter. It’s very easy to do and no need to program microcontroler. This article will give you the shematic and the component I used.

 The shematic

First the shematic. Click to enlarge:



The power supply

First, the power supply is based on a 7805 for the 5V. So you can connect a AC/DC bloc or an USB cable. The isolation is performed by a DC/DC MEV0505. I add the LC filter on the isolated 5V as explained in the datasheet.

The DMX bus

This splitter doesn’t decode the DMX. It only received the RS485 and than generate 3 RS485 outputs. Therefore, I use a MAX3082 on the input by enabling the receiver. DMX output is isolated by the ISO3086 by enabling the DRIVER.


The LED ACTIVITY is detected by the NE555. The DMX break marker should trig the NE555 and the activity LED will seems ON while DMX frame are transfered.


I have an EUROBOX 135x95x48mm which is huge enough for the PCB. The rear and front panels are 3D printed. it looks as this:

The prototype

You can find the prototype manufacturing in this article

Isolated DMX splitter : schema
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