Blink Lure DamageMaX512 - for Witches, Werewolves and Wampires - Page 1
Forum section: electronics / projects

author: RoGeorge
author_rank: Super Contributor
timestamp: October 14, 2022, 07:05:31 pm
content: Halloween is coming!It's time for a DMX512 Blinker.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 14, 2022, 08:40:03 pm
content: DMX512 is a protocol used to control the lights in concerts, automate theater stage changes, for home automation, and so on. There is plenty of info aboutDMX512, but briefly said:- can send commands to devices like laser heads, light dimmers, curtain motors, or anything else that is either an on/off device, or an analog one with many intensity levels- can be used together with a computer or with some other MIDI controllers for live shows, or for pre-recorded shows- devices can be spread over a large area using RS-485 daisy chain wires, each device has its own address(es)- the protocol is very simple and easy to use/decode even by discrete logic or by a small 8 bit MCUIn the pics it's a DIY DMX512 device. It receives commands by USB, from a computer. Can send the commands to other devices in the field, through the RS-485 transceivers, or it can decode the incoming DMX512 data stream and control a few local outputs.

author: RoGeorge
author_rank: Super Contributor
timestamp: October 24, 2022, 02:42:14 pm
content: Better be ready, it gets serious, "This Is Halloween":Here's what to do:Step 11. First thing, installQLC+. This will teach a PC to speak DMX512. The protocol is very simple. On a serial port, at the speed of 250kbps precisely, a chunk of bytes are sent one after another, 8 data bits, parity None, 2 stop bits. The very first byte is usually zero, to tell 24 up to 512 DMX values will follow. These numbers can control stage lights, direction of laser heads and so on.- aUniverseis such a serial wire through which up to 512 DMX values can be sent as 25...513 consecutive bytes.- the receivers on such a wire are calledFixtures. Afixturecan be a bulb dimmer, a laser head, a spot, etc.- the fixtures are daisy-chained, or else said the same serial wire goes from onefixtureto another, and thefixturesare all receiving the same DMX data which was sent to theirunivers. Therefore, to know what DMX values are destined to whom, eachfixturehave aDMX Address. TheDMX addresscan be set from micro-switches to be found on eachfixture, and can be between 1 and 512 (binary, so 9 micro switches per fixture, 1 for each bit). DMX addresses are chosen so they don't overlap. Often, afixturecan consume more than one DMX value. Eachfixturewill respond only to those DMX values corresponding to their DMX addressrange. For example, if afixtureis an RGB head that needs 3 bytes, one byte for each color, then thefixturewill light according to the the 3 consecutive bytes, starting with the byte that has the same index as theDMX addressof the RGBfixture.- theTerminator.Fixtureson a stage can be widespread, so they usually need long wires. The physical layer is RS-485 (which makes the link possible up to 400 meters or 1200 feet) and the cables have 120 ohms impedance. The wires of eachuniversemust end with a 120 ohmsterminatorresistor. Usually,fixtureshave each a terminator inside, and switches to enable/disable it. Only the lastfixtureshould have the terminatorenabled.- the QLC+ program we have just installed on the PC is aDMX controller, can send command to one or moreuniverses, eachuniversewith its own lightingfixtures. TheDMX controllercan send manual command, for example from sliders on the PC screen, or by reading the physical knobs and buttons of a MIDI controller (or maybe a MIDI keyboard), or it can control thefixturesaccording to internal timers, or it according to music or video, and so on.Overall, aDMX Universewill look something like this, where thefixturesare called Slave Device:Diagram fromhttps://en.wikipedia.org/wiki/DMX512

author: RoGeorge
author_rank: Super Contributor
timestamp: October 27, 2022, 03:45:21 pm
content: Step 21. For the hardware controller part, get a serial port that can work at the required 250kbps plus some RS485 buffers. The most common device that can be recognized by almost any DMX software, including by the QLC+ installed in the previous step, is probably the USB to serial bridge known as the USB OpenDMX, or the Enttec USB DMX interface. It is based on a FTDI USB to serial TTL bridge, followed by RS485 buffers.I've used anFT232RLsited on a 0.1 inch perfboard, like this:The 485 buffers areSN75176. The schematic is the typical application from the linked datasheet of each chip, put together.When plugged to an USB port the device should be detected as an UART. In Linux check with lsusb:Code:lsusb | grep FT232Bus 003 Device 009: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) ICIf the DMX interface is not accessible, add the Linux user to the 'dialout' group:Code:sudo adduser $USER dialoutThen, open QLC+, click on the 'Inputs/Outputs' tab -> 'Mapping' tab and check the corresponding 'Output' checkbox. The receiving data LED of the RL232 should light indicating the QLC+ is continuously sending DMX data to the OpenDMX interface.