Page 1 of 1

Wifi/Artnet to DMX device

Posted: Tue Apr 14, 2020 3:20 pm
by markus_b
I've created a small device to be able to drive DMX lights directly via Artnet, no DMX interface required. I've designed this to go directly inside a DMX device. This allows me to use a DMX light/device equipped like this with no DMX cabling, via wifi.

The hardware is pretty simple, a Wemos D1 ESP8266 wifi module with a Max485 level shifter for the DMX signals. The level shifter is turned off, when no matching Artnet data is received. This allows the light to be used with traditional cabling if desired.

I'm looking for feedback on my project: https://github.com/markusb/esp-dmx

Re: Wifi/Artnet to DMX device

Posted: Tue Apr 14, 2020 3:43 pm
by sandinak
This is slick. I do ALOT with ArtNet -> DMX ... been using a Raspi -> DMX Hat for most of mine and it' works rather well, but I like this as a simpler solution! some Questions:
  • I've had BAD luck using ArtNET-> Multicast .. with more than a few U, have you tested this with more than one U?
  • I've had GOOD luck using ArtNET -> Unicast .. last show was 54 U and worked mostly well.. assuming this will support Unicast?
  • Is this 2.4 or 5 Ghz?
  • are you supporting bi-directional DMX?
  • how do you set WIFI params?
  • is it remotely accessible via ssh/http for admin?
  • how do you set universe?
Do you have any examples of what it looks like created? Would love to see moar!

Re: Wifi/Artnet to DMX device

Posted: Thu Apr 16, 2020 12:34 pm
by GGGss
I'm not acquainted with this project but I can already say something about it...
sandinak wrote: Tue Apr 14, 2020 3:43 pm [*]I've had BAD luck using ArtNET-> Multicast .. with more than a few U, have you tested this with more than one U?
Wifi doesn't like multicast - you'd create too much noise. Therefore most Wifi Access Points are equipped with what is called 'storm control' - not allowing multicasts.
sandinak wrote: Tue Apr 14, 2020 3:43 pm [*]Is this 2.4 or 5 Ghz?
I hope 5 because the 2.4 will be flooded by guests looking for a signal... (I don't like wireless unless absolutely no other way)
sandinak wrote: Tue Apr 14, 2020 3:43 pm [*]are you supporting bi-directional DMX?
It's called RDM and QLC+ doesn't support RDM (yet?)
sandinak wrote: Tue Apr 14, 2020 3:43 pm [*]how do you set universe?
As a general rule, you have to add a zero-based offset; so U0 is U1 in Artnet.
Depending on the OP's setup, you have to set an Artnet base-universe and after that, the product takes care of the rest of the addressing. I've seen a couple of different setups here. If hardware or physical limits the use of channels, I configure an universe overlaps (2 devices get the info, but since only the 1/2 of ports are wired - the other device does its job having the same setting.

Re: Wifi/Artnet to DMX device

Posted: Thu Apr 16, 2020 1:15 pm
by sandinak
Good reply .. some quick notes:
  • re: wifi+multicast .. yes .. storm control can present a problem if it exists .. i've run 1-2 U over broadcast successfully tweaking params in OpenWRT based APs.
  • re: 2.4 vs 5 .. regardless of freq, if you hide the ESSID ( turn off broadcast ) that helps immensely with Guest association ( And of course WPA2 ) .. wireless actually works quite well if configured properly. I've ran 54 U over 2.4 successfully using unicast no problem ( DMX is a LOW 250 Kbps data rate compared to 802.11b 11Mbps )
  • re: RDM .. Yea .. I hope one day that can be worked in .. some of the auto-config stuff is pretty neat when it works.
  • re: Universe .. Zero-based config is correct, I was interested in how you set it per device .. EG is it hardcoded in the firmware.. etc.
Some other things that help:
  • Use a good router. I've had lots of success with OpenWRT on Archer C7 and WRT3200
  • Scope your venue before you setup and make sure the you're using the best channel(s) .. I use Wifi Analyzer on a spare tablet every time.. and adjust before setup )
  • Use as much power as you can legally and minimize distance between AP and Clients.
  • Any devices you can wire with Ethernet.. do so. Takes the load off of Wifi... Given the speeds we're dealing with you can even hop a few switches ( I think superbowl this year had 5 in line??!? Remember DMX is 250 Kbit/s .. so a few ms of latency doesn't mean much )
  • Separate networks where you can and it makes sense. My lappy QLC ArtNET comes in on the 5Ghz SSID and gets routed to the 2.4 Ghz SSID ( and ethernet ..)
  • Setup the AP such that clients aren't disassociated easily... last thing you want is the delay/load of re-association.
  • As noted above turn off ESSID broadcast (hidden).
  • Once you've setup all your devices .. use a Mac Filter to constrain to those devices. Make sure you add "uhoh" devices like spare lappy or phone.
  • Leave client isolation off .. so your lappy can talk to your fixtures... etc.

Re: Wifi/Artnet to DMX device

Posted: Fri Apr 17, 2020 5:55 am
by GGGss
add on: 250kb/s per universe in full continuous stream