Kind of OT: RS-485 to DMX-512
Trying to get a lighting controller to talk to 1986 vintage microprocessor based lighting control packs. The PHY layer of DMX-512 (lighting control protocol) is RS-485. Anyone have code samples that could be used as a starting point, or should I break down & buy the USB to DMX-512 cable?
Trying to get a lighting controller to talk to 1986 vintage microprocessor based lighting control packs.
This is my world!
The PHY layer of DMX-512 (lighting control protocol) is RS-485.
Yes. Given that it's 1986, are you 100% sure it's DMX-512? If so you are good.
Anyone have code samples that could be used as a starting point, or should I break down & buy the USB to DMX-512 cable?
You can get a cheap ($7) FTDI based USB to RS485 dongle from amazon or eBay. The FTDI chip can't natively do the proper break space but they have a trick of resetting the chip to get the proper spacing for the restart of next set of 512 channels transmitted. With this adapter (which is similar to the $50 EnTec OpenDMX) you can use free software in windows like FreeStylerDMX or QLC+, or if you wish to go the linux route there is the Linux OLA package which can do Artnet and 1.31 sACN in and translate over to physical DMX512 (via RS485 dongle.) OLA has a web interface that lets you tickle the channels with a web fader board, and could easily be scripted. At the laser enthusiasts gathering I go to I've done a presentation or two on running OLA on a PI to do cheap Artnet/1.31 in over to DMX512. I can dig up the slides. Actually, since the presentation is on the evil cloud I just opened up access and here is the steps to install the OLA bits on debian/pi: https://docs.google.com/presentation/d/1MqJrwKCAL_tw4t-VnQWevSvXTlszwFy-clEC... - Ethan O'Toole
As Ethan pointed out, the trickiest part about DMX512 w/ a UART is getting the extended break length right for the cycle restart and matching the 250 kbit/s rate. Beyond that, the transport layer matches EIA-232/485. And DMX512 isn't so non-vintage computing related. I did some faux lighting panels for a Thinking Machines CM-2 recently. The controller is built around an ESP32 with BT/Wifi. I thought about adding support for artnet so the 4096 individually dim-able LEDs can be controlled with standard DMX universes :) Have to finish the project in January. Would be a good way for non-technical museum people to setup lighting patterns. -Alan On 2018-11-30 16:46, Ethan O'Toole via vcf-midatlantic wrote:
Trying to get a lighting controller to talk to 1986 vintage microprocessor based lighting control packs.
This is my world!
The PHY layer of DMX-512 (lighting control protocol) is RS-485.
Yes. Given that it's 1986, are you 100% sure it's DMX-512? If so you are good.
Anyone have code samples that could be used as a starting point, or should I break down & buy the USB to DMX-512 cable?
You can get a cheap ($7) FTDI based USB to RS485 dongle from amazon or eBay. The FTDI chip can't natively do the proper break space but they have a trick of resetting the chip to get the proper spacing for the restart of next set of 512 channels transmitted.
With this adapter (which is similar to the $50 EnTec OpenDMX) you can use free software in windows like FreeStylerDMX or QLC+, or if you wish to go the linux route there is the Linux OLA package which can do Artnet and 1.31 sACN in and translate over to physical DMX512 (via RS485 dongle.) OLA has a web interface that lets you tickle the channels with a web fader board, and could easily be scripted.
At the laser enthusiasts gathering I go to I've done a presentation or two on running OLA on a PI to do cheap Artnet/1.31 in over to DMX512. I can dig up the slides.
Actually, since the presentation is on the evil cloud I just opened up access and here is the steps to install the OLA bits on debian/pi: https://docs.google.com/presentation/d/1MqJrwKCAL_tw4t-VnQWevSvXTlszwFy-clEC...
- Ethan O'Toole
And DMX512 isn't so non-vintage computing related. I did some faux lighting panels for a Thinking Machines CM-2 recently. The controller is built around an ESP32 with BT/Wifi. I thought about adding support for artnet so the 4096 individually dim-able LEDs can be controlled with standard DMX universes :) Have to finish the project in January. Would be a good way for non-technical museum people to setup lighting patterns. -Alan
CM/2? Where!? The one at the Mountain View Computer History Museum? I only know of that CM2 in the wild, along with the Frostberg CM-5 at the NSA museum up the road in Maryland. A Cray and a Thinking Machines were my two "grails." I managed to get one, and the sheer weight let it be the final big machine grail :-) When I saw the CM-5 at the NSA Cryptographic Museum I was floored to find out it was some 9' high and is likely to cause difficully going into a truck. Not to mention through a normal door! - Ethan
Computer Museum of America which will open in Summer'19 (along with a Cray exhibit with dozens of machines). -Alan On 2018-11-30 19:34, Ethan O'Toole wrote:
And DMX512 isn't so non-vintage computing related. I did some faux lighting panels for a Thinking Machines CM-2 recently. The controller is built around an ESP32 with BT/Wifi. I thought about adding support for artnet so the 4096 individually dim-able LEDs can be controlled with standard DMX universes :) Have to finish the project in January. Would be a good way for non-technical museum people to setup lighting patterns. -Alan
CM/2? Where!? The one at the Mountain View Computer History Museum? I only know of that CM2 in the wild, along with the Frostberg CM-5 at the NSA museum up the road in Maryland.
A Cray and a Thinking Machines were my two "grails." I managed to get one, and the sheer weight let it be the final big machine grail :-) When I saw the CM-5 at the NSA Cryptographic Museum I was floored to find out it was some 9' high and is likely to cause difficully going into a truck. Not to mention through a normal door!
- Ethan
On 11/30/2018 4:46 PM, Ethan O'Toole wrote:
Trying to get a lighting controller to talk to 1986 vintage microprocessor based lighting control packs.
This is my world!
The PHY layer of DMX-512 (lighting control protocol) is RS-485.
Yes. Given that it's 1986, are you 100% sure it's DMX-512? If so you are good.
Anyone have code samples that could be used as a starting point, or should I break down & buy the USB to DMX-512 cable?
You can get a cheap ($7) FTDI based USB to RS485 dongle from amazon or eBay. The FTDI chip can't natively do the proper break space but they have a trick of resetting the chip to get the proper spacing for the restart of next set of 512 channels transmitted.
With this adapter (which is similar to the $50 EnTec OpenDMX) you can use free software in windows like FreeStylerDMX or QLC+, or if you wish to go the linux route there is the Linux OLA package which can do Artnet and 1.31 sACN in and translate over to physical DMX512 (via RS485 dongle.) OLA has a web interface that lets you tickle the channels with a web fader board, and could easily be scripted.
At the laser enthusiasts gathering I go to I've done a presentation or two on running OLA on a PI to do cheap Artnet/1.31 in over to DMX512. I can dig up the slides.
Actually, since the presentation is on the evil cloud I just opened up access and here is the steps to install the OLA bits on debian/pi: https://docs.google.com/presentation/d/1MqJrwKCAL_tw4t-VnQWevSvXTlszwFy-clEC...
Lighting packs are Strand CD-80 with the aftermarket Johnson Systems DPC-24 control modules, so yes, it's definitely DMX-512 Looking at the Open DMX USB as an option
Lighting packs are Strand CD-80 with the aftermarket Johnson Systems DPC-24 control modules, so yes, it's definitely DMX-512
Ah okay! I thought that was pretty early for DMX-512. I remember I had some Intellabeam fixtures and they were said to "mostly work with DMX-512." I used it with a LPT dongle someone made using a PIC and it worked, then got the Entec. I've had the Entec for some 10+ years and it's had the crap kicked out of it at events and held up well. No regrets, though the Entec Pro has a bit more support (the laser show software I use, Pangolin Beyond, I think only supports the Entec Pro -- but I don't use it for DMX so not an issue for me.) The cheap dongle is these: https://www.aliexpress.com/item/NEW-USB-TO-TTL-RS485-FTDI-Interface-Board-FT... They're everywhere. You have to wire it out. Also, note that "real" interfaces like the Entecs usually have a 5 pin XLR connector that is real DMX standard versus the 3 pin mic style that is usually used (at this point Cat5 RJ45 would be much better.) On the vintage tip -- I have a Status Cue console from High End Systems and am looking for the ISA card that goes in the PC that goes with it. The software is freely downloadable, I have a luggable Pentium 1 but can't find the ISA card anywhere. - Ethan
On 11/30/18 6:14 PM, Martin Flynn via vcf-midatlantic wrote:
Lighting packs are Strand CD-80 with the aftermarket Johnson Systems DPC-24 control modules, so yes, it's definitely DMX-512
Looking at the Open DMX USB as an option
I'll bring some USB RS485 dongles tomorrow, if I can find them. -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies
On 11/30/18 4:36 PM, Martin Flynn via vcf-midatlantic wrote:
Trying to get a lighting controller to talk to 1986 vintage microprocessor based lighting control packs.
The PHY layer of DMX-512 (lighting control protocol) is RS-485.
Anyone have code samples that could be used as a starting point, or should I break down & buy the USB to DMX-512 cable?
Python has libraries (not sure that's what you want). There are also Arduino libraries. You might be able to hack together a DMX sniffer with some RS485 Chips. I have a couple of USB RS485 dongles that would allow you to toss the Python Library onto any modern computer. -- Linux Home Automation Neil Cherry ncherry@linuxha.com http://www.linuxha.com/ Main site http://linuxha.blogspot.com/ My HA Blog Author of: Linux Smart Homes For Dummies
participants (4)
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alan＠alanlee.org -
Ethan O'Toole -
Martin Flynn -
Neil Cherry