Propeller based DMX transmitter/receiver/tester...... where is it??
WBA Consulting
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While watching to banks of some theater style lighting flicker during a children's play on Sunday, I got thinking about what it would take to determine the root cause. The light unit is essentially a strip of 10 RGB lights and the first blue would flash on randomly when the unit should be fully off. Two of the light units were doing this. My first thought was a stray bit in the DMX stream, lol, but I know it could be several things.
1) Bad data coming from the light controller.
2) Bad parsing of the incoming data by the light unit.
3) Faulty blue LED driver in the light unit (which would mean nothing to do with the DMX stream)
4) ??
I figured if I could manually see the data from the lighting controller or send data to the light, I could determine which end contains the fault. Of course, being of an Engineering mindset, I first Googled "DMX Tester". I found the one listed below and thought that $275 isn't actually a bad price. However, I also thought to myself, the Propeller could smack that out...
http://nudeltadigital.com/dmxtester-2.aspx
So, here is the question: With all of the other DMX objects, projects, threads, etc out here, why isn't there code for a user friendly DMX transceiver?
1) Bad data coming from the light controller.
2) Bad parsing of the incoming data by the light unit.
3) Faulty blue LED driver in the light unit (which would mean nothing to do with the DMX stream)
4) ??
I figured if I could manually see the data from the lighting controller or send data to the light, I could determine which end contains the fault. Of course, being of an Engineering mindset, I first Googled "DMX Tester". I found the one listed below and thought that $275 isn't actually a bad price. However, I also thought to myself, the Propeller could smack that out...
http://nudeltadigital.com/dmxtester-2.aspx
So, here is the question: With all of the other DMX objects, projects, threads, etc out here, why isn't there code for a user friendly DMX transceiver?
Comments
Mine? It's under slow development process... :-)
Assuming the unit was DMX controlled, other causes of flickering are:
4) No terminator on the end of the DMX chain
5) The data line was overloaded. This depends a lot on the RS485 transmitters and receivers.
6) A dodgy lead. It happened to me recently and tracing the fault was complicated by some set covering one of the leads. The set guys had accidentally crushed one end of the cable.
There are a number of projects out there (arduino and pic). Ideally it would give you information on the entire data stream including timings of the break and mark after break lengths. I think one of the objects in the OBEX can do this? I too have thought about such a project but I have a mini scope and that I slap on the line and it does quite well at indicating the 'health' of the data stream.
In DMX, a device is either a server or client -- usually not both. I've attached my latest DMX objects in case they're helpful. to what you want to do. There are some chips that can independently RX and TX (like the MAX489); that might be helpful.
I'm not sure if it's still around, but Tim Swieter wrote a DMX object that provided analysis of the packet: length of break, MAB, packet size, etc.