Problem receiving DMX

Projects Programming
1

Hi!
I'm trying to build an Arduino DMX Receiver to control WS2812 led tape. So far I've managed to control the tape with a simple button, but now I'm stuck at the DMX part.
My setup is:
Arduino Nano
UART TTL To RS485 Two-Way Converter (ER-CIA00485T)
ArtNet Gate (ProMyk v1.2)

I'm sending DMX from MA dot2 onPC - it works perfectly, tested with a led par fixture.
To test if Arduino is receiving DMX I connected an led to digital pin 9, and the TX & RX pins of the RS485 converter to the TX & RX pins on Arduino. I combined the Blink code with DmxSerialRecv example from DMXSerial library, so that the led would be on for the number of seconds set with DMX, and if no data is received it would blink.

#include <DMXSerial.h>

#define dmxAddr     1     // dmx starting address
#define ledPin      9     // pin, where the LED is connected

void setup() {
  pinMode(ledPin, OUTPUT);       // initialize digital pin as an output.
  DMXSerial.init(DMXReceiver);   // initialize DMX receiver mode
  DMXSerial.maxChannel(1);       // limit the number of DMX channels to read in
}

void loop() {
  unsigned long lastPacket = DMXSerial.noDataSince();  // Calculate how long no data bucket was received

  if (lastPacket < 5000) {
      digitalWrite(ledPin, HIGH);           // turn the LED on 
      delay(DMXSerial.read(dmxAddr)*1000);  // wait for a number of seconds set through dmx
      digitalWrite(ledPin, LOW);            // turn the LED off 
      delay(1000);                          // wait for a second
   }
  else {
      digitalWrite(ledPin, HIGH);        // turn the LED on 
      delay(1000);                       // wait for a second
      digitalWrite(ledPin, LOW);         // turn the LED off 
      delay(1000);                       // wait for a second
  }                      
}

IMG_20211003_152430
IMG_20211003_1524301920×1291 170 KB

Unfortunately the led is constantly blinking, so I'm not receiving any data. I tried swapping the TX & RX pins and using different software (QLC+), but the result is always the same. I also tried running some code examples for DMX with neopixel, but never got any output on the led tape.
Is there something wrong in my setup? Am I missing something in the code? Any tips would be appreciated :smiley:

2

You have some nice pictures but they do not help me much. Can you post a schematic, not a frizzy picture showing all of your connections. Your code spends all of its time in delays. While in a delay it cannot do anything else.

3

How do you set the mode for it ? It can either receive or send, but not both at the same time.

have you tried swapping the leads of the DMX cable ? DMX has inverted logic compared to Serial.

4

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