More LED panels: upgrading the scrolling display

Back in winter, I posted a review of RGB LED panels with a resolution of 64x32 pixels. That gave me a 192x32-pixel scrolling display. But as it turned out once again, your appetite grows as you eat, so I decided to double the resolution—not by making it longer, but by making it taller.
Anyway, if you're interested in this topic, come on in.


This time I bought the panels from a different seller, which was a little concerning since I was worried about compatibility. But the price was noticeably lower, so I ordered three.
After a relatively short wait, I picked up a fairly large, soft “candy” at the post office, and it wasn't even in a plastic bag.


A quick aside: the seller offers free shipping if you order no more than two panels. So I placed two orders, one for two panels and one for a single panel. The seller shipped them together in one large package. It had a tracking number and was easy to track.
Inside the padded envelope were the panels wrapped in the same material, along with a set of cables.


The package included:
1. Five short ribbon cables for connecting the data line.
2. Two power cables, each with two connectors. Makes sense: there are three panels, one cable wouldn't be enough, so they included two.
3, 4. No complaints about the cables; everything is very neatly made.


And here are the panels. At first glance, they're identical to the previous ones.



While testing the panels, I put an old one next to a new one and noticed that they are in fact different, although the differences are minimal.
The new one.


Compared with the previous order, the board layout and the positions of some components are different.


The panels have markings, so I'll include them here just in case they might be useful to someone.


One more difference: the panels have arrows marking the input and output, as well as the top. Very handy and practical.


The components are exactly the same as on the previous panels. You can find more detailed photos in the previous review.


A bunch of drivers and controllers from CHIPONE


During testing, I happened to notice that one panel had either been repaired or had a manufacturing defect, and had undergone some “pre-sale preparation.” This didn't affect its performance at all, but it did leave a bit of a bad taste. I took a photo mainly to show that this can happen.


As before, the panel measures 256x128 mm, and its thickness is about the same as a matchbox.


The panel is intended for indoor use, or for use inside an enclosure, since the LEDs have no protection against water, dust, etc.


The construction is exactly the same as before: the same pile of tiny self-tapping screws and a plastic frame. I won't take it apart, since I did that last time.


As soon as I got the panels, I called the friend I'd ordered them for. He brought along the scrolling display he'd built last time, and we started tinkering with it.


At first, we got a duplicate of the first screen on the second one, but with some lines shifted. The panels were connected in series.


In short, complete chaos :)


But let's leave the image alone for now. First, we absolutely need to test the panels themselves, since last time I had a dead red LED. The seller refunded part of the cost without any questions.
By the way, the scrolling display has been in use since January this year, and it's still working perfectly—there hasn't been a single dead pixel.

Press the “test” button on the control board and watch the different patterns.


But I was more interested in two things.
1. The brightness difference between the previous panel and the new ones. I don't have any instruments for this, so I had to judge by eye. They look identical. Even if there is a difference, it’s barely noticeable.
If you turn on white on all the panels, you can use the strip for lighting. But listen to how the power supply buzzes in this mode...


2. Dead pixels. We switch on a solid fill of each color in turn and carefully look for dead pixels. I couldn’t find a single one, so let’s call this test passed too.


After the initial tests, I opened the control program and set the panel mode to 192x64, but the output was still all over the place.


Using the “scientific trial-and-error method”—or, to be more precise, after making a few logical deductions—I connected the additional panels to the second connector on the control board. At first, though, I plugged them in backwards, and the device simply wouldn’t work. It turned out that the first wire in both ribbon cables must be oriented the same way. By default, the panel connected to the controller is the last one in the row, but as far as I understand, this can be changed.

The panels are connected in exactly the same way; the new panel is at the bottom, and the old one is at the top. The photo shows where to connect them.


First test. Unfortunately, the long ribbon cable that came with the first panels was left at my friend’s workplace, so I had to connect everything using short cables. As a result, one panel “slipped” out of the frame; there was no other way, with all the connections just temporarily rigged together.


Let’s try displaying the flower image from the first review. Back then, only what is now shown on the top row was visible. Now the image is easier to make out.


I found a few more images in the examples that came with the program. Here’s another one as an example.


And this is how it will look in real life.


The third image somehow ended up split into two parts right along the boundary between the panels. It’s actually one continuous image, with the sky at the top and wheat at the bottom.


The tests were done with a new version of the program. As far as I understand, its image output capabilities have been expanded, with color, gamma correction, and so on.


The panels were sent off for modifications that same day, and were already back at work the next day :)
My friend completely rebuilt the enclosure, and now the setup looks like this.


As a little extra, here’s a video from the previous review.





That’s it. The three panels came to $50.94, compared with $57.17 last time. No complaints about the build quality; everything works great, so I can definitely recommend them. It also turned out that a suitable power supply costs even less here than in China.