Inside a wireless DMX receiver

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I feel guilty making a video about this sensibly designed system that paints it in a bad light, but we've had a pretty rough time with these units on a show that uses these in mobile risers (podiums) with video floors that the performers stand on, side RGB LED channels, RGB under-glow lighting and three costumes with 150 channels of DMX controlled addressable LEDs.
Even with external aerials on top of the risers positioned away from the metal structure, and many attempts at finding an optimum location for the multiverse transmitters that take a data feed and transmit the required number of lighting control networks, we have had very patchy results. There's a good chance that this is due to the awkward outdoor RF environment with lots of moving bodies to block the RF signal, and a metal stadium structure that doesn't lend itself well to bouncing the signal to improve its reach. But whereas previous systems like the excellent Astera Titan Tubes performed well with nothing more than an occasional delayed response when they struggled to get a solid signal, these units have done very un-showbiz things like crashing or failing to reconnect to the signal. That's resulted in missing the DMX video server trigger signals and sections of lighting either jumping through fades or locking up completely.
There's a good chance that these units will fare much better in an indoor environment with nice RF reflective walls, but they really need to tweak their software to make them reconnect properly in the instance of signal loss.
Hopefully the firmware (which we updated) will evolve with time and the bugs will be ironed out. Most of the lighting crew use City Theatrical test equipment (DMX-cats) and their DMX dimmers perform well, so hopefully this is just an issue that was more visible due to our less than ideal outdoor stadium.
Supporting the channel with a dollar or two on Patreon helps keep it independent of RU-vid's quirks, avoids intrusive mid-video adverts, gives early access, bonus footage and regular quiet Patreon live streams.
/ bigclive
#ElectronicsCreators

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6 окт 2024

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Комментарии : 439

@warphammer 2 года назад

I gave a bit of advice for someone making a... similar lighting control device for a large theme park. Eventually the decision was to pre-load the show over wifi onto the card, then merely send it a go signal with a timestamp on it. Then the GPS-laden board would just... play the show, all the myriad units running without any input at all (except maybe a stop signal if they ever had to for some reason), using the GPS for time sync. Worked a treat in a tricky RF environment, but of course the downside is you need a completely canned, almost invariable show, without fiddly humans and their imprecise timing involved.

@KeritechElectronics 2 года назад

"Fiddly humans and their imprecise timing" was such a lovely way to state it! :D

@lucidlx 2 года назад

Absolutely a great way to go. I have also done systems that broadcast a timecode over radio, with the cues stored locally in the receiving device. That way, as long as the receiver gets a snippet of timecode, it can run cues with it's internal clock, even if the radio drops out. Of course this still only works well with a locked down timecoded show.

@retrogamestudios6688 2 года назад

Need more input....atleast more details to concur

@retrogamestudios6688 2 года назад

How many universes

@Richard-dc5he 2 года назад

@@retrogamestudios6688 Doesn't matter. Timecode/RTC-driven shows are common, I've put together such systems from a mere 4 universe all the way up to around 150-200 universes, give or take a few dozen. I forget the details, it didn't really matter. You just need a controller that can store the show and play it back synced to timecode, with a sufficiently-accurate set of Real-Time-Clocks that can be remotely configured to start each segment at a precise time. Said controller lives in the remote end, and the core sends the "Go at this point in the future" commands over the unreliable link - several seconds before it actually needs to start. That last detail is the critical one. You need to know exactly when the cues must fire *several seconds* before they must do so. Which tends to make the method useless for most shows that involve squishy humans.

@EsotericArctos 2 года назад

The "multiverse receiver" looks suspiciously like an ESP8286 chip with a branded cover on it. This system looks like it could work quite well in an environment that was fairly RF quiet, or maybe using the 900MHz band, but I can imagine 2.4GHz would be pretty noisey. Thanks for tearing this down for us. I didn't feel you painted it negatively, more just that it was troublesome in your environment.

@NEWDIABLO96 Год назад

When I saw it I was thinking the same (ESP-32 actually), but pin count and tracing don’t match up

@howlingwolven 2 года назад

You should be able to get those receivers with 868 MHz (UK/EU UHF) LoRa modules in them. I’m personally not a fan of using 2G4 if I can help it, it’s just so crowded a band these days.

@PatrickColeman 2 года назад

915MHz (the US open band) is allocated to 3G/4G here, iirc. You won't compete well with a local mobile cell running at tens of watts (and Vodafone will send goons when they triangulate your position). Our open bands 868MHz or 433MHz are often quite usable in the UK depending on where you are, and the lower frequencies are absorbed less well by water-filled humans so they carry further. You can also check for clear bands and interference on site with a cheap USB software defined radio module and open source spectrum analyser software like gqrx.

@MicraHakkinen 2 года назад

@@PatrickColeman The downside of using 868 or 433MHz is that you're restricted to a low duty cycle, among other limitations. I doubt you could run a DMX universe on that frequency without busting a few regulations.

@samjonesmartin 2 года назад

@@MicraHakkinen 433MHz can also be stomped over by amateur radio ops with a fair amount of power and most repeater outputs in the UK for analog voice are at 433MHz. Been a few story's of people being locked out of there cars and garages because if this.

@gregreynolds5686 2 года назад

@@MicraHakkinen At 869.5MHz you are allowed 10% duty and 500mW.

@jonmusgrov 2 года назад

if you use the open frequencies allow in the local area you'll still be contending with all the audio equipment used at the venue. with a lot of performers using one frequency for their mix/instrument and one if the use iem, it won't take many to saturate the available frequencies. ideally if possible always run cables.

@alexatkin 2 года назад

Oh dear, two of those resistors are upside down, the electrons will fall out. No wonder its causing problems. ;)

@amtrak1007 2 года назад

I have an airport locally with these multiverse distro cards in the carpark lighting poles. I ended up having to use the 900mhz option here in the states to get it to work reliably. Cool to see this product make an appearance on your channel.

@lequart 2 года назад

Hi Clive, I work in the Entertainment production industry and if I had to guess, the first place would be the LED screens. LED screen emit a large amount of EMR (electromagnetic radiation) which wreak havoc for the RF environment. We alway use directional antennas well away from LED screens. I’d say you’re not able to get your Omni-directional antennas far enough away from the EMI produced by the LED screen. Add the relatively small wave-length and short transmission of 2.4GHz, PLUS the added noise of a stadium full of consumer devices. I’m not surprised your DMX RX/TX are struggling. That’s my guess.

@RonLaws 2 года назад

i think having everything including the kitchen toaster these days running on 2.4Ghz is a big part of the problem, we really need purpose bands for specific applications, 2.4 being wireless LAN (legacy now) 1.6 maybe should be opened up for video and 900 (for example) for low-bandwidth application such as DMX and other things that don't need huge amounts of throughput but need reliability

@testthisfordecficiencies 2 года назад

2.4ghz Wi-Fi is still much in use. Regardless of the frequency used, interference will always be an issue at some point. It is all about managing it.

@jhdemous1970 2 года назад

900 mhz is only available in the US currently.

@itmaybeokay 2 года назад

Reminds me of a wireless video link system I was using - that was just, working great in rehearsals -- but once the room filled up with people, dropped connections, streams out of sync - total postproduction nightmare. Scanned the spectrum for some kind of rogue AP that may have been causing it - but eventually settled on doing a little lab-test - sure enough, the things were SO reliant on line of sight, that 5 people standing in a row in the radio path dropped the signal to the point of cutting out. Luckily the receiver of the unit had a 1/4-20 thread on the bottom, so standard practice just became to mount it way way up high on a tall tripod over peoples' heads, and we haven't had an issue since. If they are using ESP's inside their custom reciever- they'd have to write it into their firmware - but perhaps a mesh configuration would be the way to go. This way the nodes can just hop hop hop to each other and perhaps the edgemost unit has clean LOS. Otherwise, perhaps highly directional antennas on the hub might help. I have definitely seen auto-reconnect issues on 8266's. Generally I just write some watchdog code that pings a server every 90 seconds or so and hard-reboots if it can't phone home, but that's on an ESP running on generic TCP/IP - not sure what the network stack of these looks like. I presume if it was an option, you'd have already pursued it but - have you considered just hardwiring them?

@bigclivedotcom 2 года назад

Wiring was not an option as these risers were wheeled out a reasonable distance in the dark at multiple points during the show in a short timeframe.

@ketas 2 года назад

but you're pro's. can't you use actual comms freqs? ism is ism for a reason. i know wireless mics at least here use other freqs. some are ultra low power and iirc free, some licensed. that's for .ee at least. but those 2.*ghz, 8**mhz and 4**mhz ism bands are overfilled with stuff. imagine everyone coming with phones and having bt on, maybe someone even has wifi ap on, real fun going on on the spectrum i could imagine

@sootikins 2 года назад

Auto-reconnect issues with 8266s? Gasp! Surely you jest. /sarcasm I've done a lot of 8266 stuff lately and auto-reconnect is definitely the weak spot. Pain in the arse to deal with especially when you have an 8266 acting as an AP to some 8266 stations. I ended up writing a bunch of code that makes them ping and pong each other every few seconds and hard boot if the connection is lost. Shouldn't need to resort to such violent measures... grrrr... thanks for letting me vent my frustrations ;-)

@Alacritous 2 года назад

@@ketas Using licensed spectrum can be quite pricy in some places. The hardware is more expensive AND you have to have a site license to operate it. It's not included in the cost of the product.

@johndododoe1411 2 года назад

@@Alacritous This show was big enough to get a site license for a frequency block. Problem is getting equipment that can be configured to licensed site frequencies as needed, while not inviting unlicensed idiots to activate that function. Perhaps a standard format for a government signed electronic license certificate allowing a specifief frequency and date range, which professional and prosumer equipment can check before falling back to consumer frequencies. Things like that tiny RF can need to be made to do that rather than having each equipment brand do their own checks. Then there should be a test band with 2 channels that design labs can trivially get a license for in the format used by government site licenses, just so designers can test their "licensed operation" feature in a random office building far from actual venues and EMC labs. Getting that test license should be cheap, but with effective policing of attempts of widespread use by the ignorant masses.

@SomeMorganSomewhere 2 года назад

Yeah, I'd say you're correct in your assessment of the mysterious structure between the modules, it's probably for a mixer/diplexer.

@dougle03 2 года назад

Always going to be a bit of a compromise given a single antenna trying to cover 900mz and 2.5ghz....

@johndododoe1411 2 года назад

@@dougle03 Hopefully the antenna itself would be swapped, but the connector is shared.

@Murgoh 2 года назад

I thought it was a miniature flux capacitor to eliminate latency by moving the input signal a fraction of a second to the future.

@johndododoe1411 2 года назад

Maybe it's an RF amplifier with impedance matched DC power. Or maybe it duplexes receive and transmit paths that are both in the same can.

@divingquokka 2 года назад

@@Murgoh Just my thought!

@strehlow 2 года назад

That seems like it would have been a good opportunity for the manufacturer to have an engineer on hand to collect data and assist with troubleshooting.

@paulabraham2550 2 года назад

The thing at about 5:45 that you weren't sure about; I'm pretty sure that's a flux capacitor.

@matt.604 2 года назад

It's just missing the plu tonium.

@jonmusgrov 2 года назад

it was thinking the same if you put 1.21 gigawatts through it it'll transport you back to the 90's before 2.4ghz was so swamped

@--Zook-- 2 года назад

was gonna say the same. knew there would already be a comment...lol

@moto083c 2 года назад

The spot is vacant because it hasn't been invented yet

@farmersteve129 2 года назад

2.4GHz is a minefield for such stuff where continuity of signal is important, but the firmware really ought to be able to gracefully handle such problems. I'd also suggest that from what I could see the PCB track layout could be somewhat improved and there may be some hidden issues there.

@testthisfordecficiencies 2 года назад

That is what I would assume. Proper error correction and data retransmission should be in place.

@dc-4ever201 2 года назад

Signal overlap is a major problem. I didn't realise how much until I had a wireless hub dropping out constantly, then I downloaded an app that showed me all the wireless frequencies from other people's hubs in the area, I live in a busy city centre surrounded by other flats and was amazed to see, I finally found a channel that was less populated, but mostly I hardwire my PC and TV directly to the hub to save hassle.

@MotoBarsteward 2 года назад

I'm surprised you didn't recognise the Y shaped part. It's a flux capacitor. They forgot to fit it which is why it didn't work

@johndododoe1411 2 года назад

It was definitely fitted, look again.

@Mike-H_UK 2 года назад

It will be there in 2025, believe me. I'm getting the plutonium for the De Lorean.

@uzlonewolf 2 года назад

Trying to use 2.4 GHz for an event like this is just setting up for failure. It's absolutely nuts to use it. I do love those programming connectors though. They are the Tag-Connect TC2030 system and I love them as they do not require installing any parts on the board and are much more compact than standard 0.1" pads.

@rjgscotland 2 года назад

Yes this was my thought immediately, it was doomed from the start in that environment filled with thousands of meat-bags armed with 2.4 GHz transceivers. Better to use 433 or 868 MHz, or if the duty cycle limitations prove problematic for this application given the need for constant 2 way communication, then 5.8 GHz (although consideration of antenna placement and line of sight needs to be taken more seriously in that case)

@cameronsteel6147 2 года назад

Brings back memories of a New Years gig I did a few years ago where DMX needed to be shot from the foreshore out to the end of the breakwater at the local harbour. The proprietary wireless DMX modules we had just wouldn't reach the 300m across the water, so we ended up throwing together a solution with two Ubiquiti long range WiFi radios. The connection was reliable, but the ArtNet node on the far side was much less so, especially when the local youth found the emergency stop on the generator!

@hyperfluff_folf 2 года назад

Ohhhh why can i see this in my imaginary eye? 😅

@rowanjones3476 2 года назад

At least they didn’t just steal it!

@cameronsteel6147 2 года назад

@@rowanjones3476 There was some security present, so they probably weren't game enough lol

@ricknelson947 2 года назад

Sometimes adding a higher gain antenna will make the problem worse, because it will increase the interference signal along with the desired signal. One option is to try changing the polarization of the antennas at each end most likely from vertical to horizontal. You can achieve up to 23dB of isolation from the unwanted signal if the unwanted signal is the opposite polarity. Major drawback to horizontal polarization is that it tends to be more directional. The 2.4 GHz cameras are most likely a much stronger signal and impossible to compete with. They should have coordinated with your team. The show show should have priority over them.

@theoldbigmoose 2 года назад

Also when Clyde talked about remote mounting antennas... the dB loss per foot of that coax is phenomenally bad.

@mfx1 2 года назад

A more directional aerial such as a beam will in general improve the signal to noise ratio unless the noise is coming from the same direction in which case it wont make it worse, the ratio will stay the same.

@mfx1 2 года назад

@@theoldbigmoose Yes you're better off doing all your RF conversation near to the antenna and keeping coax as short as possible unless you have the budget for a RF over fibre setup.

@ricknelson947 2 года назад

@@theoldbigmoose agreed, was trying to keep my already too long of a reply from being too long. There are always gives and takes with coax at 2.4GHz. Sometimes the loss is negated and overcome by the gain achieved by getting the antennas in a better position. Other times, not so much.

@Bubu567 2 года назад

At 2.4 ghz, I can already say with high confidence your issue was interference. Sadly that is a troublesome operating frequency anymore. Too much traffic on that band now thanks to wifi and everything 'wireless' operating in that range. It could have also been software related unless SOMETHING was absolutely swamping all possible channels, which is also a possibility. I think they make gear that can diagnose such issues. In one situation in the past, I had to change the country of a device and put it on a 'non-compliant' channel to prevent interference, but that's just asking for other troubles.

@casemodder89 2 года назад

THIS ! everyone got their fckn earplugs and bluetooth on all the fckn time. plus wifi in order to notice every possible way to enter the internet for free... wireless rõde mikes, live camera streaming and stuff doesn't help either.

@jazzdirt 2 года назад

Wireless DMX is also in itself still buggy as F. Even in a radio clean situation.. I've been testing quite a lot of them, for they would make my job so much easier.. But it tends to not work when you really need it to work.. It's still way to unreliable even in testing setups inside a faraday cage...

@matiastripaldi406 2 года назад

Imo this is a design issue. You're making a device intended to be used wirelessly in a venue full of people, which all have phones that will probably be connected to a sitewide wifi network. Who thought using 2.4ghz was a good idea in the first place? There must be other frequency ranges available to manufacturerrs

@backacheache 2 года назад

@@matiastripaldi406 perhaps if they used a 5g mobile phone network as the backhaul itd be better, that protocol is designed for crowded environments

@Aquatarkus96 2 года назад

@@backacheache Why couldn't we give the entertainment industry those frequencies and let everyone else compete for space in the 2.4 ghz band ;)

@mumblbeebee6546 2 года назад

Thanks for the insight ;) into the kit you use - and sorry to hear that you had so much pain with it - 2.4GHz is pretty swamped in show locations sadly. And once the effing Teradek units on the back of the cameras get powered on, everyone else can just pack up and go home. Teradeks are famous for spamming every single channel of the WiFi spectrum… I suspect that spread spectrum and encryption have to make another evolutionary leap before automation systems have some peace from the high bandwidth bandits… (signed: a high bandwidth bandit)

@mfx1 2 года назад

I worked for a long time in the RF world and still make stuff that relies on RF but my golden rule is if you can use cables then use F'ing cables don't use RF just to save time/cost. If you're going to use RF then build in failsafe fallbacks where the punters see something normal even if it wasn't what or when you intended, that's far better than them seeing glitchy crap.

@stuartfisher4210 2 года назад

Yup. Definitely. Working in the lighting field, this is one of my rules. Yes, wireless might be cool or convenient, but nothing beats a hard connection. Plus backup lines where appropriate/possible. You generally have to run power so you might as well run data too.

@mfx1 2 года назад

@@stuartfisher4210 Tricky for mobile platforms that use batteries or over water but for sending simple cues high power infrared is an option, I did a pyro thing many years ago which did have to be wireless and was a centrepiece so basically HAD to work, I used RF backed up by Infrared on two completely redundant systems even down to separate batteries and everything having two igniters albeit it was only operating over a short distance. For most RF stuff I'd be looking at 868MHz unless I had no other choice and particularly at low bandwidth systems such as LoRa.

@KJ6EAD 2 года назад

2.4GHz congestion is a significant problem for shows and conventions. Diversity to other bands and stronger address filtering are the only solutions I know of.

@yohojones 2 года назад

Your calm tone is so wonderful Clive. I really wish you had some longer form content to watch/listen to.

@bigclivedotcom 2 года назад

I do have some long rambling videos, but they get less views than short videos

@TiemeKuyper 2 года назад

One of the additional factors to deteriorated performance is the self-pollution. The VND14NV04 has not any EMC decoupling. It is directly coupled to the wiring which can come very close to the receiving antenna. Gate currents from the drivers will have harmonics far in GHz bands and feed through via the FET parasitic. The design should have some RF beads and decouple C's on the outputs. Might be an experiment to see whether the driving dutycyle to 100% might improve the situation so see if this is a factor. But indeed 2.4GHz as mentioned will not be the best freq to have stable communication. Further I see very little power decoupling on the board, even around the MCU.... I guess the unit will have hard times passing EMC certifications...

@cannotbeleftblank6027 2 года назад

No need to apologize. I have seen several instances of embedded devices that have this kind of failure: the lights are still blinking and it is doing its stuff but no peep of external communication whatsoever, or worse, crash completely. There's no excuse for it, test your firmware in 50 different settings and not just on the bench 1 meter apart, and expect the unexpected.

@muzikman2008 2 года назад

If it doesn't do as described reliably, you have every right to question it's integrity. Interesting kit .

@kiwiwelch3620 2 года назад

Love love love the technical breakdown of the components and architecture

@Graham_Rule 2 года назад

I thought my employers were mad to use 2.4GHz microphones in a public space with WiFi connected laptops. We used our 2.4GHz sound desk *once* before switching to wired only. And still we have had drop outs when too many people bring in their smart phones. Our capacity is around 150 people.

@seannot-telling9806 2 года назад

That RF part you were asking about happens to be the updated version of Professor Brown's Flux Capacitor. He went ahead in time and sneaked it back so he could afford to create his updated time car.

@RS-Amsterdam 2 года назад

Great video. It would be interesting if you can get hold of one of those Wifi jammers (a lot of them don't really work) and inspect them.

@microwave221 2 года назад

DMX Cat was basically Excalibur for shop-electric work, made life so much easier when testing the equipment I worked with or troubleshooting various complaints.

@256byteram 2 года назад

I worked for a company that developed a similarish product for industrial purposes. It could be used as a wireless cable substitution system but had a lot of internal intelligence around different protocols and automatic functionality. Our system was based on an off the shelf Zigbee protocol module and was incredibly robust, and it ran in the cellular frequency band instead of 2.4GHz. It looks like City Theatrical have made the rather bold decision to produce their own RF modules. I'd like to know why they went with that, given the R&D involved in getting these modules working, along with having them certified for use. Interesting stuff.

@NivagSwerdna 2 года назад

@5:55 the routing of traces in the top left is a bit pants. They should have nudged the uP lower to give a bit more wiggle room.

@jonathanfulcher602 2 года назад

Great content. Please do more of these sort of entertainment equipment teardowns!

@KeritechElectronics 2 года назад

Oooooh, it has a flux capacitor! (U3, J5-J7) LOL Interesting device indeed :)

@mikeselectricstuff 2 года назад

PCB tracks going rather too close to the large corner holes

@iamjadedhobo 2 года назад

Especially since there is enough room to route them with more clearance. Likely, the design rule checks have been setup for the TagConnect pattern which has those 4 big holes and traces that need to go between them.

@raygunsforronnie847 Год назад

Clive, the issue is the huge amount of broadband RF noise radiated by video wall panels. Serious, fire up the floor and put a spectrum analyzer antenna where the City Theatrical unit is placed and tell us what you find. I have stories about a performer who wanted to do a duet with his wife (a performer with her own career) and it included them sitting on LED floor. The RF noise floor *at the performer's IEM receivers* was 12dB over the IEM transmitter signal. The artist was "I'll fire you if you can't make this work" insistent on the choreography no changing and the LED floor be used. It got fixed by adding a transmit antenna that lowered from a lighting truss and got camouflaged as a piece of decor, but it was only a few feet above the performers. Your problem is less the wireless DMX device and mostly the insufficiently shielded LED panels and their data/power supplies.

@Richard-dc5he 2 года назад

The very best wireless system is very nearly as good as a cheap cable... 2.4GHz is a horrible mess, there are a _lot_ of devices that break the licence-free requirements, transmitting at higher powers and duty cycles than you're actually permitted to so - but it's very hard to prove who's doing it, let alone ask them to stop. And even when every device is compliant, putting ten thousand of them in close proximity tends to swamp some of them. In general you need a good directional antenna to have a hope of reliability once there's a lot of members of the public about - the camera systems often have someone operating a bucket antenna to try to ensure the link stays (mostly) up.

@74HC04 2 года назад

I am sure someone's already mentioned this, but the programming ports J1, J2 & J3 are designed for Tag-Connect connectors. I've used one of those footprints in one of my designs. They're great for adding a zero BOM cost connector to the PCB.

@mgancarzjr 2 года назад

Might even be able to get a terminal for debugging purposes if you connect a USB to JTAG bridge.

@testthisfordecficiencies 2 года назад

You can buy the multicerse chips. This is why the RF connector is on the module. Pretty cool for a manufacturer to do this.

@veraxis9961 2 года назад

To me, that small 3-way structure between the RF modules looks like it would be for an RF switch to a common output, which commonly comes in those 6-pin packages. I do not think that it would be a diplexer, as those tend to be larger in size and it seems unlikely that one would need simultaneous operation of both bands.

@neilgillies6943 2 года назад

Watched the tattoo on tv this year and remember those illuminated platforms with the singers - stunning show and always great entertainment. I can see the ending fireworks from my hoose too 😊

@UncleWalter1 2 года назад

I pretty much avoid all 2.4 GHz in critical production stuff, especially WDMX. I've had too many issues with that band being congested when people show up. Just about smart phone is pinging every wireless AP and every bluetooth device that's on is making a racket as well. Couple that with all those meatbags absorbing a bunch of the RF, you don't have a whole lot left to work with a lot of the time, especially outdoors with a lot of people.

@Dwdanieldotdd 2 года назад

If it is out of band interference from rf swamping (overloading the rf input thus desensitizeing the reciever) you can try a bandpass filter available from Murata in the sub dollar range to see if it clears things up. Good luck with it. A different receiver is likely to be much higher in price. Take care. Tootles... Wade

@Rich-TeaFPV 2 года назад

in the Fpv drone hobby, many pilots use a receiver link by a company called 'TBS', the receiver range is called 'Crossfire'. In the US it uses 915mhz but in the UK and Europe it has to use 868mhz. It has a reputation of being very reliable over long distances with exceptionally low latency. Also if your still keen on 2.4ghz the companies ImmersionRC and ELRS use 2.4ghz for low latency long range drone links. These guys are pushing the boundaries for high speed RC links in the hobby and maybe worth a look. Tony Cake of ImmersionRC really knows what he's talking about 😀👍👍

@Zadster 2 года назад

A Revision C board, and made in 2020, I wonder what their current design revision is. As an RF nerd, I would say a directional antenna on the receiver might help. Ideally on the transmitter too, but given the large physical area it all covers it may not be possible. It wouldn't need to be a long beam, just enough directivity to reduce the interference from phones, video etc on the same band. Maybe one that is circularly polarised rather than vertical. A flat patch antenna would be cheap and quite directional.

@johndododoe1411 2 года назад

This receiver being in the clothes of a dancer prevents directional antennas from ever pointing the right way, while a transmitter can be pointed to cover only the stage area needed, like a follow spot.

@SeabornNomad 2 года назад

Your videos are some of the best electronics nerd asmr and entertainment I've found. Thanks for the awesome content Clive!

@dougle03 2 года назад

Frequency choice is the core of the problem here. 2.4ghz is a very poor choice for critical comms where there are lots of people all totting a mobile phone... Might have been far better on it's alternative 900mhz version. That wifi chip is an SDR and they are poor at the best of times. DMX is not very bandwidth demanding so error correction can be cranked right up without noticeable latency. Anything wireless using public frequencies is always going to be a headache in a busy people environment. CT might want to look at adding an additional $1 RF chip to gain diversity (Just like all the radio mics and IEM's use), this way you can have a couple of patch antennas on the risers equalling a more robust signal, that and point a directional antenna at the risers when they are in play.

@SeanBZA 2 года назад

Problem is that the other bands you then run into needing to pay a pretty penny every year to renew license for the band, and the fee is not exactly cheap either. So 433MHz, 2.4G and 5G are all the ISM band where it is "free" but you also have to contend with a million other users. Probably best to invest in some directional antennas for this setup, both the transmit and receive side, and make sure they get aimed correctly, to minimise the interference experienced.

@dougle03 2 года назад

@@SeanBZA unlikely that the 433mhz band would have been saturated there in the castle unlike 2.4ghz, however the bandwidth over 433 is quite low, would be fine for the LED's but not the floor screens on those mobile podiums. Large shows like this can, I'm sure, afford licences for reserved frequencies (Like they did for their wireless mics and iem's), but none of the kit makers seem keen on doing it as the costs go up considerably as they would need frequency select interfaces ect....

@stuartfisher4210 2 года назад

Funnily enough I was chatting to CIty Theatrical at PLASA yesterday regarding their ColorFlex range. Looks great on a trade stand but interesting to hear from someone who’s actually used it.

@Black3ternity 2 года назад

Just a Network engineer but as soon as I saw the 2.4Ghz on the can I was just facepalming. The 2.4Ghz Band is "ancient" in Computer network terms and it is ALWAYS the issue with that. You only have a couple of overlap-free bands that can send and transmit with their full potential and as soon as they are full you get a mess. Not sure if you can "program" the unit with some computer or connectivity but you should check if you can reconfigure the channel they run on. If that is doable, check if you can set your stuff to Channel 1, 6 or 11. NOTHING else. These are the only Bands that do not overlap with other bands. Additionally if it has Auto-Hop enabled you should disable that because then the device does not need to re-negotiate anything and is fixed to a set channel (even if it's an overlapping one). I understand that range is priority and 5Ghz is bad for that. But there is no such thing as "rogue wifi devices" because on 2.4 Ghz everything is just messing it up. Microwave? Check. Electric motors from equipment? Check. Cable induction from powerlines? Check. Hundreds of cellphones blaring through the air looking for WiFi Accesspoints to connect to? Yep check aswell. If you can and have the permit, check for 900Mhz. The camera equipment has priority with 2.4Ghz because they will use bigger transmitters for sure to just blast everything. And your small transmitter / receiver unit will just get swamped out.

@tonyweavers4292 2 года назад

I'm suprised to see the buttons for testing are reversed. Terminal A is below button E etc.

@UpLateGeek 2 года назад

It's possible with that many people in the crowd, that quite some number of people had the hotspot option enabled on their phones, and it was transmitting on the 2.4GHz band. The way wifi works is that every (visible) network transmits a beacon at a regular interval, usually every 102.4ms. That beacon is transmitted at the lowest possible data rate, so a network with a long name can take up a substantial amount of time on the channel. If you've got hundreds of nodes beaconing, that can cause a lot of "interference", since only one node can transmit on the particular frequency at a time. Since there's only 3 non-overlapping channels at 2.4GHz, there's really not very many options to choose from, so the whole band can become congested at big public events very quickly, as modern devices monitor the whole band and switch to a less congested frequency dynamically.

@CraftMine1000 2 года назад

The signal status is probably signal to noise ratio of valid messages and thus dosent include how crowded the band is, hence why it's "good" when it's not

@richardgrier4721 2 года назад

Repeated here, because AS video is pretty darn good: A possible RF problem might come from a failure/fault in the switch, where feed-through from Tx bleeds into Rx (though not the other way). RF also isn't my area. Of course, Andreas Speiss would recommend that you test the antenna with a cheap VNA (video last week) to make sure that the antenna is suited to use at 2.4 GHz.

@jackhodgson 2 года назад

Hi Clive. Interesting stuff. Thanks. Question: Does WiFi in the UK use 2.4Ghz? It does here in the States, as does Bluetooth connectivity. A gathering that large, with a cell phone in every pocket, would be making a huge buzz of 2.4 RF. Here in the States, that's what I'd think could be your connectivity culprit.

@daveseddon5227 2 года назад

WiFi is 2.4GHz or 5GHz. Most of the Smart Home devices appear to be 2.4GHz but some will also use the 5GHz.

@strehlow 2 года назад

And of course microwave ovens are all in that band as well. Sure, they're well shielded. But with a ~1kW signal, it doesn't take much leakage to release noise that is strong relative to what these devices operate with.

@alexatkin 2 года назад

@@strehlow It boggles my mind anything still works on 2.4Ghz, given how saturated that band is. Really doesn't help smartphone manufacturers forcing everyone to Bluetooth instead of wired headphones.

@sootikins 2 года назад

They laughed at me 20 years ago when I expressed skepticism about "everything" going to 2.4GHz. "It's frequency agile" they said. "It uses super-duper whizz-bang encoding and voodoo magic protocols" they said. "It will never become too congested to work reliably" they said. Who's laughing now??

@elvishfiend 2 года назад

@@strehlow every time I use my microwave, it tanks my 2.4GHz wifi network

@gamerpaddy 2 года назад

that radio module is a 5995 multiverse. its a dedicated 2.4ghz DMX/RDM module the 5990 and 5991 modules are 900mhz, the 5994 and 5995 are 2.4ghz. and have different modulation types

@twocvbloke 2 года назад

900MHz in the UK is used by 2G GSM mobile phone signals, so that'll be why you can't use it here, as phones would interfere and vice versa, just seems a bit silly for everything to be packed into the 2.4GHz band, given that seems to be used for things like WiFi and Bluetooth as well... :\

@ulwur 2 года назад

The PCB routing around the flash memory chip.... The tiniest of traces just on the edge of the mounting hole.

@gordonm2821 2 года назад

R41 has been put in upside down this will cause back emf issues on the ocdc circuit

@jayhom5385 2 года назад

For some reason This is Spinal Tap came to mind with Nigel's wireless guitar.

@eebaker699 2 года назад

Great channel! Always like your tear downs. Maybe some other commenters are correct in thinking there's too much interference from other sources. Try this, place your operating device near or on top of an operating domestic microwave oven. The ovens operate at 2.4gHz amongst heaps of other things. See if it plays havoc on the operation. Might have to build a DIY directional antenna that just encompasses the stage area.

@andycrask3531 2 года назад

Not an expert on wireless by any means but we have had issues with nodes dropping off the network when there was a lot of noise, we had the option to change the channel as most devices use channel 1 by default. May be of no use to you at all but hey you never know

@williamarmstrong7199 2 года назад

In the UK I think the 900Mhz range is for emergancy services. 5 GHz though is avalible and with over 64 usable chanels a lot more reliable

@LeifNelandDk 2 года назад

Protection diodes probably in case the outputs are used for relays or motors.

@jerimiaus69 2 года назад

Thank you so much for this video 💙💙💙 I recently got into wireless dmx fixture building and this will be very helpful knowledge for my future endeavors

@ralphj4012 2 года назад

On some RF modules you can change the RF channel on which they operate, but this would only really be practical in fixed installations (experimenting with channels, spectrum analysers etc is no fun for temporary installations) and you would need access to the module config interface. J5, J6, J7 looks like an RF splitter (or a flux capacitor), but that's odd, the interface into these modules is usually serial data, RF is generally only used at the module's antenna output (you wouldn't combine those).

@kittenisageek 2 года назад

I run sound for a church. I had to go through and manually adjust the channels for all our wireless mics because we were getting interference from two different TV channels. We never got audible interference, but we would have mics randomly drop out due to the signal noise. As far as I could tell, we weren't actually using the same frequency as the TV. Instead, we were close enough to the broadcast station that the secondary peaks were overwhelming some of our channels with noise.

@lawdelpus 2 года назад

The component next to the rf unit is a miniature flux capacitor !

@stepheneyles2198 2 года назад

Popped round to my local Poundland after watching this but they said they've got none left... Have to be quicker next time!! ;-)) Joking aside, nice to see something more dedicated than the standard consumer stuff. Never worked with DMX but as it's RS485 based, have worked on similar stuff. Thanks 🙂

@patrickquick4340 2 года назад

About interference. I recently ran a small show in a small room in a local pub. I pre-wired the lights with a DMX radio receiver for convenience of setup. All worked beautifully at home. In the pub room the lights would respond, then not respond and then respond again a bit later - not usable! Luckily the room was small so I ran a cable from the desk to the lights and all was well. Later I ran a wifi audit app on my phone and saw loads of high-strength 2.4GHz signals. It looks as though each of the residential rooms just above the room we were in had its own wifi AP and the sheer quantity and strength of signal was swamping the DMX trasnmitter's signal.

@patrickquick4340 2 года назад

PS we use the radio DMX units in the local village hall with up to 20m throw to multiple receivers and all works seamlessly.

@hattix6713 2 года назад

J5, J6, and J7 are for additional antennae and an antenna diversity switcher (U3).

@SaltyPuglord 2 года назад

Those ST Micro VND14NV04 "MOSFETs" are actually full-on integrated circuits. They have gate control, linear current limiting, overtemp protection, and the MOSFET all on the same die. Google the part number and take a look at the data sheet. (I'd give the link here, except RU-vid tends to treats any comment with a clickable URL as "spam-until-proven-otherwise.")

@johndododoe1411 2 года назад

Except when it's actual spam, sadly.

@g7mks383 2 года назад

A cable takes some beating for reliability. Very interesting thanks.

@brakgeluid Год назад

I spotted the issue immediately on the picture. The two R 050's that are upside down!

@markfergerson2145 2 года назад

U3 is clearly the advanced flux capacitor that permits the device to access multiple universes. ;) Yeah, it's probably what combines/splits signals to the RF modules and antenna. As others have said that band is saturated with everything from your setup, cameras and customer's wifi earbuds and whatnot. Might look into hardwiring everything you can to avoid more interference.

@br6768 2 года назад

That smaller space between the two RF modules ...looks like maybe for a Flux capacitor module? Mostly for time delay (or advance) driven at 88Ghz/hr. ..It's an expensive component requiring high wattage... almost 1.21 Jiggawatts to be precise. Ok I'm done lol

@Viewer19 2 года назад

That same thing happens in Times Square on New Years Eve all the 2499 devices conflicting, Everuthing works during set up then all hell breaks loose at showtime

@5Breaker 2 года назад

That thing you're not sure about is clearly a flux compensator. Can't you see that? :D

@mikgus 2 года назад

A bit disappointed that i had scroll down this far to find this comment

@Sparrotz 2 года назад

U3 must be an flux capacitor

@BjornV78 2 года назад

1:40 i can be wrong, but that antenna seems to be for 5Ghz and not 2.4Ghz. Normally antenna's for 2.4Ghz are longer. Besides that, the 2.4Ghz band is all filled up with WiFi signals of different kinds, what you can try is to change the channel of your 2.4Ghz connection. There are useally 13 channels, with channel 6 the most used one, changing the channel or set the channel fixed can help.

@williamromine5715 2 года назад

I don't know why I subscribed to this channel, because I am completely lost as what he is describing, but today I wasn't even sure what "universe" he is from. Then, I looked at the comments, and found a whole "universe" of inhabitants who live in his "universe". I'm the "alien" in this "universe", and I'm calling home for someone to come and get me! Until that happens, I'll still subscribe because his voice is so calming.

@DaveF. 2 года назад

Nice looking PCB. Your comments about interference just threw me back to an episode of Only Fools and Horses when Dell's knock-off dodgy brick-like mobile phone did nothing other than change the pub TV channel everytime he typed a number into its keypad.

@general0ne Год назад

That missing component between the two receiver modules is where the Flux Capacitor is supposed to be fitted!

@Gin-toki 2 года назад

The connector (J4) next to the micro controller is most likely a serial (RS232 compatible) debugging port. They're often left still functional after a product has been sold and can typically give various useful information when hooked up to a PC.

@johndododoe1411 2 года назад

Or it might be JTAG or microprocessor specific debug pins. Even JTAG 4-wire doesn't have a standard pin assignment in the TagConnect documentation.

@Gin-toki 2 года назад

@@johndododoe1411 Correct, it can be various things, however the programming socket is most likely the JTAG connector for the MCU. Also in my experience, the serial debug is typically a 3pin connector with 100mil spacing between the pins (as in the image) a standard pin header.

@johndododoe1411 2 года назад

@@Gin-toki Once a designer uses TagConnect plugs, they might as well use the smallest one (this one!) for 3-pin debug and specify pin assignment in the service documentation.

@Gin-toki 2 года назад

@@johndododoe1411 I'm not a big fan of that type of connector, the holse in the PCB takes up a lot of real estate. For the 3 pin connector, it's easy enough to trace it to the MCU and look in its datasheet to see if they're UART pins or something else. My guess is that they are :)

@johndododoe1411 2 года назад

@@Gin-toki Obviously the designer of this board liked TagConnect, so your dislike is not relevant. As a surface layer feature, tracing connections from 6-pin TagConnect to the chip should be even easier than for a through hole connector that might connect at any layer.

@jayzo 2 года назад

The 900MHz option would need to be 868MHz in the UK. I have a special radio system for a DIY drone using an 868MHz radio. I'd assume the radio modules are standard modules and can be swapped, so if there was a model with an 868MHz receiver you could desolder it and replace it with the 900MHz Radio module (probably the 2.4GHz radio too but I'd make absolutely no guarantee on that as I'm using a completely different device to base that information on. If you did decide to go that route I'd try and work out what Ofcom says about the frequency's usage limits (power and duty cycle limits on transmission) because the rules aren't that transparent nor very easy to understand if it applies in your _specific_ usage case, in fact I'm stopping using my 868MHz radios until I can get a definitive answer in case Ofcom appears out of nowhere one day and I get a massive fine get my drone's £200 radio system confiscated for unwittingly breaking the rules.

@MrFixiit 2 года назад

U3 is for the flux capacitor

@NiyaKouya 2 года назад

Neat device, but opting for the 2.4GHz band was probably the worst decision, with all the other protocols (WLAN, BT, ZigBee and most likely a bunch more) already fighting for air time... If there's an alternative that uses a sub-1GHz band there's a really good chance that it would work with less issues.

@Spiderelectron 2 года назад

You can use 868 Mhz in the uk - but ony for short bursts, not for continuous transmission.

@transmitterguy478 2 года назад

The circuit board says 2019, probably designed in 2018. They probably never figured that 2.4Ghz device usage would explode as it has and probably has so much RF crap coming into the antenna, from other devices, the RF front end can't handle it.

@yellowcrescent 2 года назад

2.4GHz has gotten super crowded. Even in my own house here in the US, for some reason my living room is like a 2.4GHz twilight zone. Bluetooth and wireless devices that use 2.4GHz in there won't operate further than about 3 feet without severe interference. So like my wireless mouse, keyboard, wireless game controllers have a very poor signal. Out of curiosity I checked nearby signals with WiGLE Wifi (Android App), and it detected around 50 (!) other mostly Bluetooth/BLE and WiFi signals from who-knows-where. And I'm in a detached single family home. Although my living room windows point across a big greenway/right-of-way to the backyards of other homes, so I imagine that's the reason, and the shape of the room (half-vaulted ceiling) acts like a big reflector.

@davidfalconer8913 2 года назад

I am an RF engineer ( ! ) ..... try making your own ( 50 Ω dipole ) antenna , the two prongs should be calculated to be exactly ¼ wavelengths long ( or ½ wave from end to end ! ) use the formula V = F x W ( V is the velocity of light , F is the frequency ( Hz ) and W the wavelength in metres , there is probably an on line calculator for this ? ) this should match reasonably to 50 ohm cable , you can then move it or rotate it to try and block out the pesky camera folk ( ? ) , you might put the dipole outside the lighting room to see if that helps , you might try a sharp notch filter in line , but they can be very expensive ! ... if you are desperate you might be better off using 800 / 900 MHz RF bits - n - bobs ... BTW in my school days the theatre lighting used MONSTA rheostats ( and NO electronics ! ) set to about 75 % , the projection room was warm - n - toastie in the winter ! !

@todayonthebench 2 года назад

Using 2.4 GHz signaling is practically asking to have interference in a crowded venue. A lot of people will have the WiFi on their phones active and all these will sit there idly sending out their packets asking if there is any WiFi access points nearby among other things. Not to mention those who use their phone as a WiFi hotspot for their friends or their other WiFi using devices. Then there is Bluetooth operating in the same band, so add on all wireless headsets, a fair amount of smart watches, etc, etc. 433 MHz might actually be a lot quieter, but ideally one would want the thing operating in its own band, just like wireless microphones do.

@tautology_zero 2 года назад

J4 jumped out at me as being UART (and the pins from the MCU match it) - it would be interesting to solder some jumpers to it to see what it presents. It'd be nice to get a read of the SPI flash too as the MCU has 512 kB of onboard memory flash with 128 kB SRAM so shouldn't need external flash.

@seanet1310 2 года назад

2.4GHz is often very congested so it is often worth avoiding it and going to an alternative frequency where possible. Most regulators e.g OFCOM have multiple frequency bands that are allowable for short range devices like this. Without going to site with a spec an, it is hard to tell what might be wrong. If they are using fixed frequency, it could be an overlapping wifi or similar channel. They may be transmitting very low power and that could be a problem if they are designed for world wide use and complying with the lowest common denominator. They could have a poorly implanted frequency hopping design and getting out of sync between transmitter and receiver. There could be a rouge transmitter or faulty equipment with unintentional transmissions in the frequency band providing in band interference. The rf module may have poor out of band rejection. Hopefully firmware fixable but depends on the root cause

@starghost09 2 года назад

I have been doing lighting full time for many years now. Wireless is cool, but I avoid it all cost for DMX, it's just not at a proper standard of reliability for a show environment. If I absolutely must use it I use as few DMX channel as possible, that has seem to be a trick that helps with me in the US.

@MD_Builds 2 года назад

That RF module looks like a straight up ESP32

@benjaminsmith3625 2 года назад

Interesting seeing TagConnect on the board. I guess they program the boards individually and in the UK rather than just ordering the ROMs pre-programmed.

@fuzzy1dk 2 года назад

must be for debugging/development, for production you'd be using a test fixture with pogo pins, not plugging in a connector

@johndododoe1411 2 года назад

@@fuzzy1dk TagConnect is a handle with pogo pins. Well suited for low volume production with the option of putting that pogo pattern on a robot for ramping up production.

@rpavlik1 2 года назад

I doubt they have availability of factory programmed stm32 right now (honestly they probably don't have any availability 🤦), tag connect is just a few plated pads/test points and a stupidly expensive patented connector. ($50 for 6 pogo pins?) Whether or not it's used in production, may be useful to use in development.

@thephantom1492 2 года назад

Hey Clive, you should try some 2.4GHz directional antenna, some mini yagi. It would help ALOT for RF noise!

@wafikiri_ 2 года назад

5:50 It is obvious that it is a flux capacitor like that in the DeLorean.

@lesliefranklin1870 2 года назад

If I recall correctly, a lot of WiFi uses 2.4GHz. And some people use their mobile phones as "hot spots".

@carlubambi5541 2 года назад

Fantastic as always .!Wish I could buy you a drink .I bet your brother knows a few places .Oh wait .let's hit the bothy !He's got a nice stash there ! Set up some lights and a wood pizza oven and grill and we can open up a club !