EEVblog #928 - Jaycar DMX RGB LED Lights Teardown

[EEVblog]

Inside the cheap arse Jaycar SL3467 "Rave" DMX controlled RGB LED disco party lights scored for $1 from the dumpster sale. Did Dave get ripped off?
http://www.jaycar.com.au/multicoloured-led-party-or-stage-lighting-kit-with-stand-controller/p/SL3467

[Brumby]

Some useful bits there - but the overall idea was not executed too well.  $1 was a fair price.

If you're done with the gear, I'd be interested in the lights and control unit... might be able to make something of it.  Not really interested in the foot controllers.

Open to offers?

[boffin]

It's built to a price for sure, but it can still put out some serious light.

On the red channel that 1st panel has a blown LED or dropper (there's 4 LEDs that look like they should be lit), and probably draws closer to 2W if they were all working.  And yes, Red is generally higher efficiency. 
5W ea for the G and B , and you're looking at a 12W LED panel, which is probably between 80-100W incandescent bulb. four of those should put our some serious eye burning if you point them in the same direction.

Should be a snap to fix it up, and get it working, and it could be handy for some things (turn your head 180 degrees to read that LED panel). 

Even if you just wired each panel for +12/GND, it could be useful lighting for something.

[calexanian]

There appeared to be some unsoldered joints on the control board. Wonder if thats whats causing the failure. Otherwise you basically got some scrap for a buck. Here in my area we would use that for target practice out in a field somewhere.

[boffin]

There appeared to be some unsoldered joints on the control board. Wonder if thats whats causing the failure. Otherwise you basically got some scrap for a buck. Here in my area we would use that for target practice out in a field somewhere.

the unsoldered joints are just the other side of the push switches.  They just soldered 2 of 4 joints for speed (and cheapness)

[pickle9000]

Just for the housings I'd buy a few. Looks like an OK mounting system for the lights and it's easy enough to buy led panels that would fit in. Looks like they swivel. Would I used the rest of it? Probably not but it can always be donated to a person in need.

As for Dave a buck for a teardown video? That's a no-brainer,   

[nomis]

Note that the display actually seems to display something useful - it is just upside down in the video.

I can see Addr, dISP, SLAv, which are familiar to me from other cheap ass dmx equipment...

Note that the UI usually is pretty horrible though... 

[haybailes]

i picked some up as well from the sale
and one of the funny things i saw on my was the pins going through the board some were cut but most were not pic below
also the red leds have a patten but just have gone/blown, also pic below in a different spot from yours
i got board the other day and started putting an arduino with them for when i go camping because why not
keep an eye out on www.tinkersprojects.com i will post on here when i make something work if i can

[Twoflower]

Looking at the display I would think the DMX controller is not designed for down under. The product is meant to be sold on the other side of the world.

It looks if the pins were ripped out of the connector and stuck in the faulty socket.

[JimP]

Dave, while watching the video on the Jaycar LED Lights, you were showing the menu on the interface box and saying there was gobbletygook on the display.  I thought this too initially, but after a few seconds I saw what is happening.
When you first turned it on that it showed what looks to be "E 45", but it's actually "Sh 3" upside down.  If you turn the interface box upside down, you'll notice quite a few readable words (?) on the display.  At 3:55 it looks like "SLae", at 4:03 it's actually "Addr", at 4:04, it's "SLnd", at 4:06, it "Chnd". etc., etc.
I don't know wexactly what they mean, but I'm sure "Addr" is address, "CHnd" is probably channel, etc.

Just wanted to let you know the observation I made.  Although several have likely already alerted you to it.

Keep up the good job.

Regards,
Jim

[jitter]

For me the most interesting part would be the PSU. I mean a 100 W for $1?
It looks like a decent quality PSU and the caps used are Aishi. Not the most well known brand, but I've said it before on this forum, I've come to trust these Chinese caps as if they were Japanese branded ones.
Most recently I tore down two LED-bulbs that had done their promised 25,000 hours. The Aishi caps sat smack in the middle of the heat and measured just fine capacity and ESR wise.

So yeah, salvage the footpedal and the PSU, dump the rest.

[tigrou]

I'm wondering how is the DMX signal processed.
Is it done entirely by the Amtel16 microcontroller ? Is a 16mhz cpu fast enough to analyse (in realtime) a 250 kbit/s signal (and also at the same time drive the LEDs) ?

[thm_w]

I'm wondering how is the DMX signal processed.
Is it done entirely by the Amtel16 microcontroller ? Is a 16mhz cpu fast enough to analyse (in realtime) a 250 kbit/s signal (and also at the same time drive the LEDs) ?

DMX signal, its about 40Hz, 22ms max: http://ricardo-dias.com/2013/03/29/dmx512-protocol-at-low-level/
So some dead time if necessary, but its going to be handled by hardware UART so will not use much resources.
There would not be much analysis, if byte = address then process, otherwise ignore it.

The LEDs might take more work as its done with shift registers.

[eamoex]

Love Dave's videos, but this one should not have aired. We get it: Chinese make crap. Get over it. My guess is it's too big an object for a two-minute teardown and not sophistcated enough for a full-featured teardown or even repair. I dunno, but it did not feel right.

Again I usually love the videos and I don't mean to offense; I really frankly think this is hurting the blog's quality.

[Towger]

Is a 16mhz cpu fast enough to analyse (in realtime) a 250 kbit/s signal (and also at the same time drive the LEDs) ?

Upsidedown display: There is often an option to reverse the display direction. As with many of these cheap units they are not very intuitive and you really need to RTFM to work out all the menu options. In saying that most are the same in basic operation, but you are doing well if the manual matches the units operation 100%.

Build quality: I have seen worse in cheap led disco lights.  However they are not even CC driving the LEDs, even the cheapest allieexpress units are current driven these days.

MCPU: Expect their refresh rate to be slow and strobe like mad when videoed. Their dimming curve to be crap and snap out at the lower end.  Colour mixing to be bad and change as they are dimmed.

[NickS]

Chinese make crap. Get over it.

I'm slightly shocked that Jaycar (reputable Australian retailer) actually sold something that didn't even have a brand.
They sell some cheap stuff, but it's generally got a brand of some kind on it.

[Brumby]

I'm slightly shocked that Jaycar (reputable Australian retailer) actually sold something that didn't even have a brand.
They sell some cheap stuff, but it's generally got a brand of some kind on it.

Certainly, price considerations would have been high on the list, but I'm not.

"Rave" was printed on the carry bag - and that's enough to call it having a brand.  The gear itself is "branded by association".

[EEVblog]

"Rave" was printed on the carry bag - and that's enough to call it having a brand.  The gear itself is "branded by association".

Yeah, I think this (and the other "Rave" gear) essentially has no brand. At least I haven't been able to find the OEM.
Jaycar probably wouldn't have custom ordered the design of them, so likely it does exist somewhere else? 

[Vgkid]

Thanks for the teardown. Those lights and PSU are still useable, along with that foot switch.

[GabYoung92]

The most common fault on these units was that the LED's would burn out!

[jitter]

Love Dave's videos, but this one should not have aired. We get it: Chinese make crap. Get over it. My guess is it's too big an object for a two-minute teardown and not sophistcated enough for a full-featured teardown or even repair. I dunno, but it did not feel right.

Again I usually love the videos and I don't mean to offense; I really frankly think this is hurting the blog's quality.

I actually enjoyed the video, so the not airing thing is something I don't agree on and I also can't imagine why it would hurt the blog.
This particular tear down subject turned out to be of low quality (aka "crap"), but that was a design decision. This was designed and built down to a price, but the same factory might be churning out stuff for the pro brands as well (the usage of A-branded semiconductors instead of Wun Hung Lo's best on the control board might be an indication of that).
And not all the Chinese design and manufacture is crap, I would not have any second thoughts on using (e.g.) Mean Well PSUs despite the somewhat funny or tacky sounding name.

[pickle9000]

Hey Dave,

How about a "What is crap / crusty video?". A comparison between 1970's and 80 consumer gear and modern consumer gear. How similar some of the old stuff is to modern low end products. No need to get fancy early calculator, and then one from a dollar store. Perhaps include a price or two.

Building down to a price is a part of the game when production runs are high.

[Fungus]

I'm wondering how is the DMX signal processed.
Is it done entirely by the Amtel16 microcontroller ? Is a 16mhz cpu fast enough to analyse (in realtime) a 250 kbit/s signal (and also at the same time drive the LEDs) ?

Sure it is.

AVR chips have hardware to receive the individual bits then set a signal when a full group of them have arrived.

If it's 8 bits per byte then bytes are arriving at 32kHz. 16MHz is plenty fast enough to process that.

[Fungus]

We get it: Chinese make crap. Get over it.

This particular tear down subject turned out to be of low quality (aka "crap"), but that was a design decision. This was designed and built down to a price, but the same factory might be churning out stuff for the pro brands as well.

I don't like to see the use of Chinese as an adjective. It is a cheap shot (pun intended). I particularly think it is unfair when the customer, a Western customer, is ordering it for resale and seeking to maximise profits.

Yep. The Chinese are perfectly capable of making good quality stuff (everybody knows they're good at math!)

If they're exporting crap it's because the round-eyes are buying it by the container-load.

It's also because the round eyes aren't above exploiting people who are desperate enough to work for pennies per hour. People who live in glass houses...

Again I usually love the videos and I don't mean to offense; I really frankly think this is hurting the blog's quality.

Luckily for the rest of us, the blog isn't individually tailored for you.

[EEVblog]

Again I usually love the videos and I don't mean to offense; I really frankly think this is hurting the blog's quality.

Luckily for the rest of us, the blog isn't individually tailored for you.

Exactly.
And the video was as advertised, it was a teardown of a cheap Jaycar light.
Didn't turn into a great video because, well, turns out there wasn't anything interesting in it, and quite frankly I couldn't have been bothered doing anything else with it like reverse engineering it or experimenting. So, meh, I just uploaded what I had. I'm guilty of uploading a fairly boring and low-ish technical quality content video, sue me, that happens. 90% of the people who rated the video thought it was ok enough, so, well, there's your answer I guess.