Cheap mass communications ideas

Go To Last Post
34 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Hi guys,

My turn to ask for suggestions.

My daughter-in-law is a costume designer for a children's performance academy. Today she asked me for suggestions of how to add lighting effects to 60 costumes for a presentation in January 2014.

Her initial idea is to synchronise the individual leds to either the music and/or the performer's movements. I like the WS2812 RGB devices and these could be wired into the costumes with conductive thread, but the means of activating them all at the same time to the music begs the question... what comms to use for 60 performers on a single stage at the same time. There will be lots of organic obstructions, so I am open to suggestions.

I envisage using one of these 18560-based power packs.

Cheers,

Ross

Attachment(s): 

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I'd try to use RFM12 or RFM22 in 433MHz or similar that's legal for you. You'd have to drive that with a microprocessor in each player unit.

Alternative: Use XBee Series 1 at 2.4GHz - and their virtual-wire capability. The central base can be a Series 1 Pro, higher power, and have a good antenna. No microprocessor needed, no code on the player end. Has about 5 digital lines that can be toggled or used as one-shots, based on what you do with the software on the central station.

In either case, a broadcast address can be used to blink the lights from a transmitting controller connected via USB/serial to a laptop. There, the complicated software could written in, say, Visual Basic for Microsoft Studio Express. It could also eavesdrop on the audio leaving the PC for the PA system. Audio on PC from mp3 file(s).

The hard part would be the code to blink the lights based on an audio equalizer or FFT or some such.

A friend has all-off-the-shelf Christmas lights (110VAC, not LED), and a controller that does the audio analysis and uses a script for music, etc. No doubt, an overkill here.

Being a one time event (?) doing the wireless simply, without doing a from-scratch protocol would seem important.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

also these... same form factor

http://jeelabs.com/products/jeenode

use an AVR

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I'm pretty sure I read some "news" article recently where this was done at some event(sorry I can't be more specific - didn't get enough sleep to wash the toxins out of my brain last night.
I think I remember they used IR, even though that sounds unlikely.

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
I think I remember they used IR, even though that sounds unlikely.

Yeah, i also remembered having heard of this one, but viewed IR as being inappropriate for a dancing group, since the movements of the performers would surely block the IR beam frequently.

Einstein was right: "Two things are unlimited: the universe and the human stupidity. But i'm not quite sure about the former..."

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks Steve. Some interesting reading material.

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Yes, the designer was on 'Freaks and showed his audience bracelet, but I couldn't find it when I did a search with "bracelet" and "audience".

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

http://rhb.me/2012/11/synchronized-led-ring-construction-details/

Yes, it's true, I just like filling in that captcha...

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

it at the european song contest.
And they could control different areas, so it sounds correct that it was controlled by IR.
Good IR is cheap and easy to deal with, and since the transmitter can be powered from AC, just run the IR LED's hard, and have a lot of them.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:

it at the european song contest.
And they could control different areas, so it sounds correct that it was controlled by IR.

There was a discussion of this here at 'freaks just after the event. Some 'freak that attended actually pried open the gadget afterwards and we had a tech discussion. Should be fairly easy to locate the thread, since the approximate date is known.

It could be that the discussion was piggybacked onto a one or two years ealier thread re ESC.

[I am currently - last few days - CAPTCHAd for every post I make. This is horrible - I'm beginning to think pictures of fornication is not that bad on a tech site...]

As of January 15, 2018, Site fix-up work has begun! Now do your part and report any bugs or deficiencies here

No guarantees, but if we don't report problems they won't get much of  a chance to be fixed! Details/discussions at link given just above.

 

"Some questions have no answers."[C Baird] "There comes a point where the spoon-feeding has to stop and the independent thinking has to start." [C Lawson] "There are always ways to disagree, without being disagreeable."[E Weddington] "Words represent concepts. Use the wrong words, communicate the wrong concept." [J Morin] "Persistence only goes so far if you set yourself up for failure." [Kartman]

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

sparrow2 wrote:
it at the european song contest.
And they could control different areas, so it sounds correct that it was controlled by IR.
Good IR is cheap and easy to deal with, and since the transmitter can be powered from AC, just run the IR LED's hard, and have a lot of them.

Good job! That was the one!

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@Ross, do you have a link to that power pack you picture?

John

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

If you need to use 433(.8)MHz the cheapest way (at least here), is to buy 3 light switches with one remote (99Kr= $18US).

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Coldplay also did it on the Mylo Xyloto tour. You can find teardowns of the (AVR based) wristband online

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

60 NRF modules wouldn't cost much these days. You'd have to sew them into the costumes carefully so the kids didn't complain about the sharp corners and prickly pins. This would let you remote control them.

Maybe use some of those MMA accelerometers to try to pick up the kid's motion?

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Does it need to be that complicated?

I'd have thought that a 32kHz watch crystal would be stable enough, once synchronised, for any given performance length. So now all you need to do is to get them all into step.

Fit each one with a cheap IR detector diode and make a master IR transmitter. All you need is a pulse of IR to start them all off together.

#1 Hardware Problem? https://www.avrfreaks.net/forum/...

#2 Hardware Problem? Read AVR042.

#3 All grounds are not created equal

#4 Have you proved your chip is running at xxMHz?

#5 "If you think you need floating point to solve the problem then you don't understand the problem. If you really do need floating point then you have a problem you do not understand."

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

There's an idea. Preprogram them all, and all you need is a way to pace it with the performance. Or maybe the director would pace the performance with the kids' blinking costumes?

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

60 RF modules could get a bit expensive.

Additionally, depending upon the RF platform used one would need to make sure that there was a broadcast to all units packet, so that all of the kid's costumes would respond essentially simultaneously.

IR might work, with a lot of IR transmitters mounted above the stage aiming downwards at the kids. Each costume would need one, or more, IR receivers aimed upwards and in a skewed angle as a back up for when the primary sensor was blocked, or otherwise had a weak signal. One doesn't want 55 kid's costumes all working as desired, and a few scattered kid's costumes out of synch with the rest.

My first thought, if the goal is to primarily synch with the music, was to just put a microphone on each child's module. Clearly all of the kids on stage will be able to hear the music being played.

Running a Goertzel algorithm instead of a true FFT (DFT) would allow for some simple audio spectrum processing. Although, truth be known, for a simple 3 or 4 audio bands, Base...Treble, using op-amps and filters would be possible. (How about that, a tie in to the Where's all the circuits these days Thread.) But I wouldn't want to hand assemble the 60+ circuits with op-amp filters...

As a spin off, one might consider using ultrasound to control the 60+ modules. Each module has a "mic", but one that listens to 30KHz, above the human's hearing range. One has one or two piezo / speakers mounted aiming at the stage, and you send your data modulated on the inaudible ultrasonic frequency. Cheaper than RF, perhaps.

JC

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

There are some guys in the christmas lighting community using the NRF24L01 modules for pixel control. The modules can be had for around $1 through eBay. I'd search around on diychristmas.org and doityourselfchristmas.com. One member is running roughly 3k pixels wireless, driven by Vixen (free sequencing software).

Also, for an IR solution search for "head blinker" on those sites. There were a few guys reversing Disney's "Glow with the show" stuff and they implemented their own IR version of it.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Perhaps take a look at a Audio induction loop.
And how a electronic dog fence works.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@John

The power pack is a "generic" one although it did have a packaging name but that is long gone from my workshop and memory. Here is one on eBay. Typically they use the Li-Po 18650 battery rated at around 2500mAHr.

http://www.ebay.com/itm/2600mAh-...

And here is my local shop's price list for them. Probably some brand names available to you.

Cheers,

Ross

Attachment(s): 

Ross McKenzie ValuSoft Melbourne Australia

Last Edited: Sat. Oct 19, 2013 - 12:16 AM
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@guys.

Thanks so much for your great suggestions. I will sit down with Jen and see what she really needs and be better prepared for her "no-knack" questions. :lol:

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Guys sorry for delay but I need to say... AWESOME...
This idea is that ideas that we have but to make it real, it is hard... The result is fantastic...

Regards,

Bruno Muswieck

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks, Ross.

John

Four legs good, two legs bad, three legs stable.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I'd probably go with the cheap nordic NRF modules for the receive end. Small, about 1.50USD per receiver, hard to beat. Just add your AVR, battery and string of addressable RGB LEDs. Shove the electronics into a little plastic box. Only a 3 pin connector out to the led strip.

Here's the trick:
They make higher power version of the nordic modules with external antennas. Only cost a few bucks more.

You get really good range when you use these with a decent antennae. But you do get odd 'dead' spots.

The nordic chip has up to 6 receive 'pipes'.

So I'd use two (or more) of the higher power transmitters, one on each end of the stage with good antennas. Transmit your control packets redundantly on two sequential pipes so you wind up with a reasonably reliable link. Pretty low latency too.

You could save yourself a lot of soldering / sewing if you can use one of the pre-made led strips / tapes.

Some of the newer individually addressable leds are just 4 pins. Power, gnd, data in, and data out.
For example: http://goo.gl/82xZdY

So they daisey chain with just three wires. They need a fast 800khc nrz data stream. Can do it on an AVR but it's a little tricky.

Very simple and flexible system, you can change your led 'show' at the master station and sync to the audio program or stage lights.

Could be a really slick system, not even that pricey. But you still need to deal with battery charging stations, any lithium battery safety issues, and lots of little details.

-carl

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Quote:
60 costumes

That is a very low quantity. I would use some off-the shelf RF technology (zigbee, bluetooth or perhaps nordic chips). The Ir would be good if these were 60k.

No RSTDISBL, no fun!

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I've been having lots of fun with the NRF's. I call them "Nordics." Just had to buy some more at 10 for $10.

If you don't know my whole story, keep your mouth shut.

If you know my whole story, you're an accomplice. Keep your mouth shut. 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Re IR,
I think the mouse ears are a pretty nifty implementation.

I saw a led costume dance setup using IR in the past, but they needed an array of emitters on the ceiling, and an upward facing IR pickup in the dancers costume's headpiece. It's another wire, and the location of the sensor is fiddly. Too easy to block the ir sensor.

But with the mouse ears, it's basically already a hat. Disney can flood the venue with the control IR carrier and get pretty good coverage with a cheap pickup in the ears. You need pretty powerful IR emitters, but they can do that at the park.

I like the rf solution for this application, less directional. You also don't need expensive arrays of IR emitters. Much less wiring.

These are just sooo cheap and easy to use. http://goo.gl/5yWGyu

This is one of the external antenna version. You'd just need a couple of these. One master and some repeater/slaves.

http://goo.gl/XaAFGh

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

Thanks guys.

@Carl you might be interested in these at a markedly cheaper price.

http://www.aliexpress.com/store/...

Cheers,

Ross

Ross McKenzie ValuSoft Melbourne Australia

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@Ross,

Not really if you factor in shipping for just 100. Much better in larger quantities. They must be cranking out miles of those led strip lights.

I linked to that guy on ebay because there were some additional technical notes in his listing, he's also shipping from the US. BTW, His 100 pc price is closer to .27 even beating aliexpress for these smaller quantities.

The drive waveform for those devices is somewhat annoying. Very timing sensitive. But a few people have figured out how drive them from AVRs or ARMs. Either bitbanging or using SPI in some weird mode.

-carl

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

@Ross
You are right. Much better in quantity.

If you actually buy a 1000 the price gets down to .15 each. That seems silly cheap.

Now if I only had a use for 1000 of them.

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

How about a current loop (such as is used for hearing aids)?

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0