Unexpected / uncontrollable DMX output

[ecoluke]

Hi,

Hardware:

1. I bought this shield: https://www.tindie.com/products/Conceptinetics/25kv-isolated-dmx-512-shield-for-arduino-r2/?pt=full_prod_search
2. I am using an Arduino UNO.

Preamble: I initially installed the conceptinetics DMX library. I was able to get the light to behave normally - channel 1 is master dimmer, 2=R, 3=G, 4=B.

The conceptinetics library uses serial to send DMX and I ultimately need to use serial to control the DMX as in your SerialToDMX example - which I am very excited about using - so I am trying to make this library work for that reason.

Issue: I installed the DMXSimple library and have managed to get some light to come out of my light - but it is confusing and makes no sense to me and I wonder if you might have any idea what is happening?

This is the code:

`#include <DmxSimple.h>

void setup() {

DmxSimple.usePin(2);

DmxSimple.maxChannel(32);

/* Set channel 1 on the light (total dimmer) to max (255) ** so that values for channels R (2), G (3) and B (4) are visible.*/ DmxSimple.write(1, 255);

}

void loop() { int x = 1; for (int i = 0; 256 > i > 0; i = i + x){ // Fade the green channel in and out DmxSimple.write(3, i); if (i >= 255) x = -1; if (i <= 0) x = 1;
} }`

What should happen is a green fade in and out - which works in the conceptinetics library.

What comes out is irregular red flashes.

Other weirdness: If I change the line DmxSimple.write(3, i); to DmxSimple.write(2, i); I still get red flashes but they are spaced differently. Any other channel - nothing.

If I change the line DmxSimple.maxChannel(64); to 32 or 4 or any other value then the red flashes also change their spacing.

Question: Do you have any ideas or suggestions about what may be amiss as I feel like I am really missing a big part of the picture?

Thanks,

Luke

[ecoluke]

Solution:

To anyone trying to get this to work:

I managed to get it to work on an modern UNO using this shield: https://www.tindie.com/products/Conceptinetics/25kv-isolated-dmx-512-shield-for-arduino-r2/?pt=full_prod_search

You need to add in the following code to the setup() function:

pinMode(2, OUTPUT); digitalWrite(2, HIGH); DmxSimple.usePin(4);

Then you need to set the jumpers:

EN DE TX-io RX-io

[haarts]

Sound similar to https://github.com/PaulStoffregen/DmxSimple/issues/3

[simon-lucas]

I believe @ecoluke 's code may not be correct – at least for the non-isolated version of the DMX Shield I am using. So, with the DMXSimple library, I made sure the pin being set for output in setup(), match the pin being used by the shield.

#define DMXPIN   4

void setup() {
  pinMode(DMXPIN, OUTPUT);
  digitalWrite(DMXPIN, HIGH);
  DmxSimple.usePin(DMXPIN);
  DmxSimple.maxChannel(5); //my number of channels


}

[wyethan]

I believe @ecoluke 's code may not be correct – at least for the non-isolated version of the DMX Shield I am using. So, with the DMXSimple library, I made sure the pin being set for output in setup(), match the pin being used by the shield.

#define DMXPIN   4

void setup() {
  pinMode(DMXPIN, OUTPUT);
  digitalWrite(DMXPIN, HIGH);
  DmxSimple.usePin(DMXPIN);
  DmxSimple.maxChannel(5); //my number of channels


}

I tried this code, and it didn't work at first. But when I tried to change the parameter of DmxSimple.maxChannel() to 512 or 256 or 128 according to this discussion (https://www.reddit.com/r/arduino/comments/3tmhge/tinkerkit_dmx_master_shield_not_working_help/), it did work.