Alternate Pixel Controller

P

P. Short

Super Moderator
Staff member
OK, I've wasted a few hours this afternoon working on a derivative of the px11 controller from a few years back. This board is roughly 2" x 3" with 4 14-pin PICs (of which there are about 8 different parts that could be used) and a Wemos Mini D1. The default build would support up to 1200 pixels (4 output channels of up to 300 pixels each). One major benefit of this design is that it would be totally open-source (including placing the gerber files in the open OshPark library), so that people would not be as dependent on various storefronts in this era of supply-chain problems.

Obviously this board design might want some refinement, and I'm not going to do much more with it until and unless there becomes a need for it (hopefully not). The PIC firmware would be an easy modification to the PX11 firmware, and hopefully the Wemos software could be easily ported from current designs. Anyway, it's something that might be worth thinking about.
 

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A more modular version. These boards can either stack (not really recommended), or overlay each other (the right connector of one board overlaying the left connector of the next board). The rows of connectors are 1" apart, as are the centers of the corner cutouts, so these boards can sit nicely in some of the CG enclosures (certainly the CG500, of which I have several). Also, these will be less costly for me to prototype.

As before, there will be adjusting before sending out for prototypes (at the very least, moving the connectors up, adding a bypass capacitor, and some silkscreen text, and possibly some status LEDs).

Not shown would be a carrier for the Wemos module (which would also include voltage regulators and possibly a 74HCT125 for buffering the signals going to the PICs).
 

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This looks really neat Phil. I'm not a pixel guy but I do like the playing around aspect of them(I have a few px1's just for that). I love the whole bringing pixels back to the diy roots(even though you've done all the work, but it's still more fun than just buying things).
 
That's likely the form factor that I'll use for the Wemos shield, as all of the boards have mounting holes/openings on 1" centers in both directions atm.
 
With 14-pin DIP sockets, is this essentially a board with four PIC16F1825 chips, fed by data from the Wemos? It's a nifty idea, Phil!
 
I'm now totally confused. Why does anybody care about this, other than being nice guys trying to avoid hurting my feelings? This is only meant as a fall-back solution for later in the year if the supply chain conditions make it difficult to obtain store-front controllers. Apart from being diy so that people can obtain (i.e. make) controllers if the bigger guys have problems, it will likely be more expensive, less capable, and require people to break out their soldering irons and PIC programmers.

After thinking about it while attempting to sleep (us older guys sometimes have that problem), I'm now a bit concerned about the throughput of the system. The difficulty is not performance at the PIC end of things, but I'm worried if the Wemos will be up it. Looking first at the pixel output side of things, I'm targetting for 1200 total pixels at 40 fps, which would require the PIC input bus to support 40 * 1200 * 24 = 1.152 Mbs. This is well within the constraints of both async serial channels and the SPI bus. There are two different ways of modifying the px1 code to support this, as there is no longer the Renard protocol in play. My main concern is whether or not the 8266 can be programmed to simultaneously receive that much data over Wifi while sending that same amount of data out to the PICs using conventional IPv4 protocols. If this presents a problem the fallback position is decrease the number of PICs associated with each 8266 board, as they are cheap and seem to be quite available.
 
I believe I saw that the 8266 cannot simultaneously do an ADC read and connect to Wifi at the same time. So I think you've got a point there. Currently I see ESP32's in at $3.25 on Ali.
 
1pet2_9 said:
I believe I saw that the 8266 cannot simultaneously do an ADC read and connect to Wifi at the same time. So I think you've got a point there. Currently I see ESP32's in at $3.25 on Ali.
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I think that you're replying to the wrong thread.
 
You said you didn't think the 8266 could send and receive at the same time, and that the 8266 is cheap and available. it seems the 8266 cannot even receive ADC and Wifi at the same time, and the ESP32 is cheap and available, too.

But I can bow out; no matter. I don't have a dog in this race.
 
There was another thread that has had a little activity regarding the 8266 ADC, and I thought that you meant to comment on that.

As I understand the ADC vs WiFi issue of the 8266, the problem is that the ADC is used to help measure the WiFi signal strength when the WiFi is active. If it turns out that the ESP32 improves throughput, I'm willing to go that route. I'll know pretty soon if there are issues with using an 8266-based board for this project.
 
P. Short said:
I'm now totally confused. Why does anybody care about this, other than being nice guys trying to avoid hurting my feelings? This is only meant as a fall-back solution for later in the year if the supply chain conditions make it difficult to obtain store-front controllers. Apart from being diy so that people can obtain (i.e. make) controllers if the bigger guys have problems, it will likely be more expensive, less capable, and require people to break out their soldering irons and PIC programmers.
Click to expand...

I think it's because people like constructing their own things. There's more pride in the effort; it's more internally rewarding. When you purchase a piece of gear and implement it, it doesn't deliver quite the same level of personal satisfaction as when "I built it" is in there somewhere.
 
dirknerkle said:
I think it's because people like constructing their own things. There's more pride in the effort; it's more internally rewarding. When you purchase a piece of gear and implement it, it doesn't deliver quite the same level of personal satisfaction as when "I built it" is in there somewhere.
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YEP! That would be me!
I really like the PB16 just for that reason, Plus the open source. I can order my own boards, source my own BOM, then put it all togeather.
I have been learning how to use KiCad because of that project also. I hope to one day to be able to design ALL of my Own controllers AC and Pixel. It won't
happen any time soon but l'm learning more every year. I'm sure the AC controllers will come first, LOL!
I like building things and especially soldering!! Soldering boards 7 years ago got me hooked. I made up my mind then that I would pursue this as far as I could.
After all, is it not DO-It-Yourself. The way I look at it is I'm faking it untill I MAKE IT.
I'll be watching this, I might have to make a few of these just to learn something NEW.
 
While I'm still going ahead with the modular version (because I like doing things myself), this ends up being a bit pointless in light of the various ESPixelStick designs. Pixel splitters might be a bit more useful for people who want multiple outputs for whatever reason.
 
i would like to add, that there are people on here that do not have the knowledge to develope their own controllers from scratch. Some get the electronic side behind the logic, some are happy getting a circuit board and BOM and solder at home, others are slower and afraid to mess up and like a tested board delivered. This hobby, like almost all others, have different levels of abilities, and those of us that have a weakness in the development side (speaking for myself) love that others are doing and sharing this.

My only concern is understanding what all these new controllers do and how to use them in my display. I get that they run pixels. I know just enough to get my E682 (self assembled) controllers up and running with my SS24's (self assembled). But when i see these new controllers coming out, i wonder, what am i missing, how can i use this and add to my show.

just my 0.02
 
Agreed, and although it's not the original topic of this thread, I will put my 2 cents in. I stumbled on this site a years ago while looking for some interesting electronics projects to get into. Before here, I could only find little gadgets that had little or no use/interest to me.
So, I got to this site and was able to learn a ton(what a rabbit hole it turned out to be) simple due to the fact that the code was readily available, the schematics were readily available and the people here have always been more than willing to help with any questions.
So, mostly thanks to Phils designs, I've learned pretty much everything I know about electronics and programming pics(and quite a lot about C# programming to boot). I think that is somewhat missing from the pixel universe(pun intended).
So, when I see a pixel project, I pay attention for the learning aspect of it. I don't ever plan on adding pixels to my display.

Ok, stepping away from the podium now...ha
 
ctmal said:
I stumbled on this site a years ago while looking for some interesting electronics projects to get into
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Still off-topic, but for me it was stumbling onto computerchristmas.com when I was looking for information on SSRs.
 
ben&bobbi said:
i would like to add, that there are people on here that do not have the knowledge to develope their own controllers from scratch. Some get the electronic side behind the logic, some are happy getting a circuit board and BOM and solder at home, others are slower and afraid to mess up and like a tested board delivered. This hobby, like almost all others, have different levels of abilities
Click to expand...

Not just ability, but time. I've programmed mbed platform and STM's (which make Arduinos look like kids' toys), but the whole display takes a gargantuan amount of time, and I have to set priorities. I'm dealing with mounting issues on the house, engineering a good mega tree, weatherproofing testing, trying to route long data lines over coax, Renard's to test, and assuming Renard's even work downstream from a smart receiver I still have to integrate all those AC lights into Xlights. Even the ws2811 packet stripper is higher priority, because that lets me make pixel sticks and meteor showers without having to loopback the data line; but even that I don't have the time or the Arduino minis for. Oh yeah, and a day job.
 
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