Pixel mapping supplies

Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
Hi all,
We are hoping to do Curious Incident of the Dog in the Nighttime and would like to branch out into pixel mapping. We would like to create a similar grid feep with pixels at the intersections of the grid. Comes out to be over 400 pixels. I am assuming that we need to purchase Very bright RGB Bullet Leds that can also be controlled via DMX. So we are not sure what LEDs to go with and which controllers. The brief search I did turned up a lot of products but they seemed to mostly prewired tapes ropes etc and we would need something that we can determine positions of.

Any product recommendations, or resources are helpful
Thanks!
 

Lynnchesque

Active Member
Joined
Feb 28, 2019
Location
Fresno, CA
How big is the grid? For something large my first thought is something like the chauvet festoon. But 400 pixels is a lot. Some kind of pixel tape solution is probably the most economical, but im not sure how far apart you can order your pixels spaced. Woe to be the tech cutting and re soldering 400 pixels to space them out.
The other thing to consider is that 400 pixels will eat up 3 universes of dmx. Make sure your show control will handle that, or maybe invest in something like madmapper which gives (nearly) unlimited Artnet universes.
 

Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
I am looking at 3'x3' grid with a pixel at each intersectiion, so its a lot for sure and there has to be the ability to link them together without having to cut tap and solder, that seems like a recipe for failure.
I am aware of the three universe requirement and I am working on that front now in preparation. We have an Ion XE20 console so I am hoping the mapping will be doable.
 

sk8rsdad

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Premium Member
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Aug 15, 2008
Location
Ottawa
Totally possible with the Ion. There are companies on Aliexpress that will make a grid or strings with whatever spacing you want. Metric spacings are readiliy available. Imperial measurement will be custom order. When I did Curious Incident I ordered WS2813 weatherproof strips from Xnbada since it was less expensive and more effective for what we were trying to do. We didn't have the budget or rigging capability for floor projections.

The DMXkings LeDMX4 PRO is a reliable controller that drives a lot of pixels.

This floor is run by an Ion Classic so the Ion XE won't even break a sweat.

1592999891474.png
 

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soundman

Well-Known Member
Joined
Sep 4, 2003
Location
Nashville TN
Hi all,
We are hoping to do Curious Incident of the Dog in the Nighttime and would like to branch out into pixel mapping. We would like to create a similar grid feep with pixels at the intersections of the grid. Comes out to be over 400 pixels. I am assuming that we need to purchase Very bright RGB Bullet Leds that can also be controlled via DMX. So we are not sure what LEDs to go with and which controllers. The brief search I did turned up a lot of products but they seemed to mostly prewired tapes ropes etc and we would need something that we can determine positions of.

Any product recommendations, or resources are helpful
Thanks!
What about something like these LED 'chips' You would need to find/build a ton of 3' 3 wire JST jumpers or work with the seller to get some made with 24" tails to save on connections.

I would suggest a demo in the space if possible. I'm not sure how well the dots will read under stage lights.
 

Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
Totally possible with the Ion. There are companies on Aliexpress that will make a grid or strings with whatever spacing you want. Metric spacings are readiliy available. Imperial measurement will be custom order. When I did Curious Incident I ordered WS2813 weatherproof strips from Xnbada since it was less expensive and more effective for what we were trying to do. We didn't have the budget or rigging capability for floor projections.

The DMXkings LeDMX4 PRO is a reliable controller that drives a lot of pixels.
Thanks for pointing me in the right direction! The controller is cheaper than imagined and it seems like one controller could do the entire project. Yet cheap enough I could use more if need be for easier wiring, I.e maybe one per wall for example.
 

sk8rsdad

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Premium Member
Fight Leukemia
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Aug 15, 2008
Location
Ottawa
Something I am a little fuzzy on. If we wire a bunch of chip and or bullet leds together, how does each led know its address?
It's managed by the controller but is largely sequential. Pixel strings listen to a stream of bits that get clocked in. The first pixel on the string grabs the first N bits then latches. The next pixel grabs the next N, and so on. For an RGB string that would be 24 bits (3 bytes) per pixel. The controller takes care of assembling the bit string by transcoding the DMX, sACN, or Art-Net message it receives from the console.

Most controllers can handle a wide range of pixel protocols with settings that allow grouping of pixels, colour order (RGB, BGR, etc.), refresh rate, clock rate, zigzag, etc. The controller manages every pixel but the console doesn't have to. For my floor every line segment is a single RGB 8-bit LED to the Ion so 15 pixels per channel.

Another way to keep the channel count manageable on the console is to offload playback to the controller. The LeDMX4 PRO (and likely others) can store shows as files on an SD card and the controller can be patched in the console to act as a poor man's media server where a DMX address maps to a file playback instruction. It's not as much fun nor as flexible but it means you can build a show with some other software.
 
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Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
Also when you run hundreds of leds through the controller it seems like you would need
It's managed by the controller but is largely sequential. Pixel strings listen to a stream of bits that get clocked in. The first pixel on the string grabs the first N bits then latches. The next pixel grabs the next N, and so on. For an RGB string that would be 24 bits (3 bytes) per pixel. The controller takes care of assembling the bit string by transcoding the DMX, sACN, or Art-Net message it receives from the console.

Most controllers can handle a wide range of pixel protocols with settings that allow grouping of pixels, colour order (RGB, BGR, etc.), refresh rate, clock rate, zigzag, etc. The controller manages every pixel but the console doesn't have to. For my floor every line segment is a single RGB 8-bit LED to the Ion so 15 pixels per channel.

Another way to keep the channel count manageable on the console is to offload playback to the controller. The LeDMX4 PRO (and likely others) can store shows as files on an SD card and the controller can be patched in the console to act as a poor man's media server where a DMX address maps to a file playback instruction. It's not as much fun nor as flexible but it means you can build a show with some other software.
So if you had a batch of Leds not in a string, or if you switched the order of leds, would the controller still communicate with them? I.e are each led preloaded with an address?
 

DrewE

Well-Known Member
Joined
Mar 18, 2019
Location
Vermont
So if you had a batch of Leds not in a string, or if you switched the order of leds, would the controller still communicate with them? I.e are each led preloaded with an address?
The LEDs need to be in one or more strings (electrically speaking) for the system to work properly.

They are generally not preloaded with any sort of an address. The protocol instead works something like passing out papers around a meeting room (well, an ideal meeting room): you take a stack, and hand it to the first person. He or she takes a copy of the top of the stack, and hands the rest to the next person, who takes the top one (the second one initially) and hands the rest to the third. Eventually the last person gets the last paper. If the papers were all different and had some defined order, you'd end up with the people holding the right papers in that order. If two people swapped seats before passing around the papers, they'd still get the papers in the right order by seat, but of course the people would end up with different papers since they moved.

The nice thing about this, or at least one nice thing, is that all the individual pixel brains can be identical and quite simple and hence inexpensive to manufacture. If they had their own identity or address, that would have to be programmed into each one by the manufacturer or user, possibly involving another manufacturing step on a not inexpensive tool (a chip tester or laser fuser most likely) and maybe more steps in fabrication to be able to create the programmable elements on the chip. The brain in the LED itself would also be a little more complicated, and hence probably physically larger and thus more expensive to make. Microchip manufacturing cost is directly related to the physical size of the chip (amongst other things).
 

Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
The LEDs need to be in one or more strings (electrically speaking) for the system to work properly.

They are generally not preloaded with any sort of an address. The protocol instead works something like passing out papers around a meeting room (well, an ideal meeting room): you take a stack, and hand it to the first person. He or she takes a copy of the top of the stack, and hands the rest to the next person, who takes the top one (the second one initially) and hands the rest to the third. Eventually the last person gets the last paper. If the papers were all different and had some defined order, you'd end up with the people holding the right papers in that order. If two people swapped seats before passing around the papers, they'd still get the papers in the right order by seat, but of course the people would end up with different papers since they moved.

The nice thing about this, or at least one nice thing, is that all the individual pixel brains can be identical and quite simple and hence inexpensive to manufacture. If they had their own identity or address, that would have to be programmed into each one by the manufacturer or user, possibly involving another manufacturing step on a not inexpensive tool (a chip tester or laser fuser most likely) and maybe more steps in fabrication to be able to create the programmable elements on the chip. The brain in the LED itself would also be a little more complicated, and hence probably physically larger and thus more expensive to make. Microchip manufacturing cost is directly related to the physical size of the chip (amongst other things).
i think i get it and that is an excellent anaolgy. So if the "papers" each named a color(mix of 3 channels). Ie red, blue, green, purple, orange, yellow in that order and you switched 2 of the people (leds), the color order would be preserved. So if i bought a bulk collection of individual leds and wired them into a string could I control them with one of the Sacn controllers mentioned above or do they need to be already wired into a strand?
 

soundman

Well-Known Member
Joined
Sep 4, 2003
Location
Nashville TN
i think i get it and that is an excellent anaolgy. So if the "papers" each named a color(mix of 3 channels). Ie red, blue, green, purple, orange, yellow in that order and you switched 2 of the people (leds), the color order would be preserved. So if i bought a bulk collection of individual leds and wired them into a string could I control them with one of the Sacn controllers mentioned above or do they need to be already wired into a strand?
The controller talks to the driver chip on each pixel. Individual LEDs will not work.

Check out something like https://www.adafruit.com/product/1655 that has a ws2811 chip onboard.
 

DrewE

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Joined
Mar 18, 2019
Location
Vermont
i think i get it and that is an excellent anaolgy. So if the "papers" each named a color(mix of 3 channels). Ie red, blue, green, purple, orange, yellow in that order and you switched 2 of the people (leds), the color order would be preserved. So if i bought a bulk collection of individual leds and wired them into a string could I control them with one of the Sacn controllers mentioned above or do they need to be already wired into a strand?
As soundman mentions, you do need proper pixel units, not merely generic LEDs that have no little brain (controller) in them. I probably should not have called them LEDs. That being said, yes you can wire up your own pixel units from...well, wherever you sourced them...into a string and use them with a compatible Sacn controller, rather than buying a pre-manufactured strand or tape or what have you. There are various form factors available from the usual places, including ones such as those soundman linked to where the LEDs and controller are all built into a single component, as well as controller chips by themselves for use with external (ordinary) LEDs if you're wanting to do even more electronic assembly and/or have more specialized needs.

(It's also unfortunately confusing that the little brain for each pixel is called a controller, and yet the box that formats and sends data to all the pixels in the string is also a controller.)
 

Frank

Member
Joined
Mar 23, 2009
Location
Maine
Where and how can I learn more about this technology and where it's used? Sounds like somthing I don't know much about.

Thanks!
 

Jackalope

Active Member
Joined
Dec 5, 2009
Location
Central Coast California
These replies have been so helpful! Thanks to all who threw in there expertise. I am looking forward to getting some of this under my belt soon.
Next question... Brightness. Which spec should I use to evaluate an LED's ability to compete with stage lighting and what minimum would you recommend?