Q Light Controller+

Hi all

I ran a recent show using show using these very effectively. They are about US$10 from Aliexpress
You have to make your own box with power supply.
I had to add a diode on the receiver unit as the fixture it was connecting to was sending data on the dmx line when it does not get data. This would make the wireless receiver unit start transmitting with no way to switch back. And since it is on pole up high... Adding a diode cut off this incoming signal and it could sync with my transmitter unit.

Just adding my 2 cents to this post. While I am very new to DMX I can confirm these units do indeed work great.
I have a an outside event where I need to send DMX signal across a lake(~200m) and simulcast up a forested embankment. So far the test runs(at the venue in question) have proved the concept. Very happy with the range and stability of these cheap units. Here they are boxed up.

One of the requirements for this event was to simulate lightning. I have to synchronise "lightning" lights with thunder clap audio track. But that's a story for another post

Hi
What are the names or where to find those wireless devices - please.
WHat to search for on Aliexpress.

A quick note about these devices ... they work well in static situations where you can find a 'clean' channel. Our tour used them on and off and there were several instances where we had to re-channel ALL the dongles ( lowering a truss in preshow sucks. ) because of conflicts.

Ok folks a few words about these wireless DMX boards and modules from the likes of Donner etc.

If your DMX show relies on everything being absolutely reliable DO NOT use these type of wireless DMX products!

There are lots of reasons for this. Let me explain.

I've reverse engineered the radio protocol these units/boards use to transmit & receive DMX wirelessly. They're all based on clones of the NRF24L01 wireless chipset and feature a power amplifier for transmission (beyond legal 2.4GHz IISM band power levels in most countries), with a low noise amplifier for reception. The output power level from the NF24L01 chip is 0dBM, but after the PA stage you're likely to get +10dBM - adding the 3dBM gain whip antenna likely makes these devices exceed legal power limits on most countries. There might be a get-out here because they don't spend all their time transmitting, so maybe they escape the legal limitation due to their duty cycle being around 10% (that is to say, the legal limits are usually based on average power level, which when a device isn't transmitting all the time would be lower). An 8 bit MCU performs translation between DMX & wireless data - or vice versa.

They are NOT frequency hopping devices. They do NOT seek to find a spare radio channel to operate on. The 'channel' selection thing (where you cycle the onboard flashing LED between one of 7 colours) does NOT decide what frequency/channel it operates on!
When you first power up a receiver, it goes looking for a transmitter on one of 127 channels. If it finds one with the same ID number as it is set to, it will start spitting DMX out.

If DMX is found at its input when it's powered on, it'll begin to transmit shortly after doing a channel 'scan'. During this scan it doesn't actually look for a clear channel, it's only really looking for one of its own kind. So if you have a wifi device nearby when you turn a wireless DMX transmitter on it might very well pick the same radio frequency as the wifi & start blasting all over it. There is literally NO way to control what radio frequency these devices operate on without modifying the firmware on the boards.

I've used these devices in my mobile DJ setups for years now (fitted the boards inside all my lights) & have never had any issues with them other than a few boards going faulty over time - but I don't typically use them over long distances & have so far not run into any problems with interference or signal strength. I've also ran two different sets of lights on different IDs in the same room without any issues (ie 2 DMX universes).

If you want PROFESSIONAL, RELIABLE (and FCC approved) wireless DMX for a critical application, look elsewhere such as the awesome (and much more expensive) W-DMX products.

Wow .. really nice breakdown here. Well done! I use these often and learned more about em .. given the problems i've had I can see them in a .. ahem .. new light and given I use WiFi on the stage anyway .. I'll probably move everything else over. Much appreciated!!

See also, the max frame rate these things can deliver is about 33hz. That's with fully loaded DMX frames going into a transmitter. Send fewer channels & you can have faster updates. Yes, really

Come to think, that might be why trying to use a tx/Rx pair to sync up identical lights (master/slave) sometimes won't work (it seems to depend on the fixtures) . Haha!

More news!

I've done further reverse engineering investigation and found that if you send less channels in your dmx solution (ie less than a full universe) the net frame rate over the wireless link can increase. This is because a transmitter only sends wireless packets for the amount of dmx frames it gets.

So if you only need 256 dmx channels or less set your dmx system to send only that amount then you can benefit from an increased frame rate for smoother fades etc. I doubt most people would ever notice the difference, but once you see frames being skipped you can't unsee them I find.

See also, I've detailed how I reverse engineered the protocol on my blog which you can reach here:
https://juskihackery.wordpress.com/

With this information it's quite easy to cook up your own compatible transmit/receive system using only a cheap Arduino type processor and inexpensive NRF24L01 module connected to its SPI pins.