LEGO DMX Fire Machine

Second LEGO DMX fixture: a Fire Machine 🙂
Similar script on EV3, listening to DMX channel 1 and reacting to just two values:

• 255 turns the BIC lighter ON
• 0 turns it OFF again

Working quite good with QLC+ as a DMX controller (at 9 Hz DMX frame rate) and other DMX fixtures on the loop (in this video a Fonestar PAR-18L set to DMX channel 2):

‘DMXfire.py’ script:

#!/usr/bin/env python3

from ev3dev2.motor import MediumMotor, OUTPUT_A, SpeedPercent
from time import sleep
import pyftdi.serialext

port = pyftdi.serialext.serial_for_url('ftdi://ftdi:232:AG0KAEQB/1', baudrate=250000)

#works good with QLC+ at 9 Hz
port.timeout = 0.0226

# clear input buffer (not sure if everything needed)
port.reset_input_buffer()
port.read(514)
port.reset_input_buffer()

channels = [0]*512
CH_FIRE = 1

fire = MediumMotor(OUTPUT_A)
fire.reset()
fire.position_sp = 0
fire.speed_sp = 1560

fireON = False

while True:
    port.reset_input_buffer()
    dmx_data = port.read(514)

    i = 0
    error = False
    for b in dmx_data:
        if i == 0 or i == 1:
            if b != 0:
                error = True
        else:
            channels[i-2] = b
        i = i + 1
    if error:
        # first 2 bytes should be zero ("start-of-packet procedure" and "start frame") 
        print("Error!")
    else:   
        if channels[CH_FIRE -1] == 255:
            if fireON == False:
                # turn Fire ON
                print('Fire triggered ON')
                fireON = True
                fire.position_sp = 3050
                fire.run_to_abs_pos()
        elif channels[CH_FIRE -1] == 0:
            if fireON == True:
            # turn Fire OFF 
            print('Fire triggered OFF')
            fireON = False 
            fire.position_sp = 0
            fire.run_to_abs_pos() 
    print("FireON: ", fireON)
    sleep(0.1)

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