OPTA and DMX with Integrated RS485 Hardware

Official Hardware Opta
1

I want to control LED lights using the DMX protocol and the integrated RS485 hardware of OPTA.
I found the ArduinoDMX.h library with its example code, but I haven't achieved any results. (I tried using a 120-ohm resistor).

I think the problem might be figuring out which pins the RS485 hardware is connected to.

Does anyone have any ideas why it’s not working?

/*
  DMX Blink

  This sketch toggles the value of DMX channel 1 between 255 and 0.

  Circuit:
   - DMX light
   - MKR board
   - MKR 485 shield
     - ISO GND connected to DMX light GND (pin 1)
     - Y connected to DMX light Data + (pin 2)
     - Z connected to DMX light Data - (pin 3)
     - Jumper positions
       - Z \/\/ Y set to ON

  created 5 July 2018
  by Sandeep Mistry
*/

#include <ArduinoRS485.h> // the ArduinoDMX library depends on ArduinoRS485
#include <ArduinoDMX.h>

const int universeSize = 16;

void setup() {
  Serial.begin(9600);
  while (!Serial);

  // initialize the DMX library with the universe size
  if (!DMX.begin(universeSize)) {
    Serial.println("Failed to initialize DMX!");
    while (1); // wait for ever
  }
}

void loop() {
  // set channel 1 value to 255
  DMX.beginTransmission();
  DMX.write(1, 255);
  DMX.endTransmission();

  delay(1000);

  // set channel 1 value to 0
  DMX.beginTransmission();
  DMX.write(1, 0);
  DMX.endTransmission();

  delay(1000);
}
2

I've no experience with an OPTA, but this web page may be of help:
https://docs.arduino.cc/tutorials/opta/getting-started-with-rs485/
There seems to be some additional work required to calculate the preDelay and postDelay values which are used by the RS485 setDelays function call.

See if that helps.

3

Decrease the duration of this delay to 60 ms instead of 1000:

the ArduinoDMX library is not very efficient and if you block by a long delay there is no refresh or generation of the DMX. You have to refresh by executing the DMX.begin, DMX.write and DMX.end.

I use other DMX libraries but they are not compatible with the Opta.

pert 4

@fdu01 please use English when posting in the forum's English language categories.

You are welcome to compose posts in your native language, then run it through a machine translation service (e.g., Google Translate) and post that translated text.

We do have a dedicated forum category for discussions in the French language: Français