PCB Routing Time!

First, here's the board in a 3D viewer so we have a nice cover image :-)

So it always starts with a rough plan of the component arrangement, that's the first thing I did.

Then came the final layout where everything is a bit more compact, and I'm confident I can route everything well without running into space issues. Of course, the board is also under 100x100mm to keep PCB production costs within budget.

Next, I routed the power lines. For VUSB, VEXT(ern), and VBUS, I used double the trace width, leaving everything else at its default values. Then I connected the display cable and easily achieved roughly equal trace lengths for each color.

Finally, I filled everything with vias around the important traces for the colors and the port. I have no idea if that makes any difference and reduces noise, but we'll see. The ground planes are of course also essential.

that's it for today, I have started with the repository, readme and bom.csv but jlcpcb has some problems on all my devices so I cannot log in to check prices for the actual pcb. well will see, hopefully tomorrow.

Schematic Speedrun

As described, I started with the 40-pin ribbon cable header and the 6-pin header. Copilot told me the Molex connectors should fit most AliExpress displays. I cobbled together the connections myself from other projects, and especially from the NHD-5.0-800480TF-ATXL#CTP display, which uses the same driver directly on the flex cable.

Then I added the USB port, decoupling capacitors, a power LED, and provided 3.3 volts for the ESP32. Incidentally, throughout the entire process, I always looked up the components on LCSC and entered them directly into KiCad, so I took care of that at the same time.

I then added an LED driver that generates the required PWM signal for the display and wired it accordingly.

And lastly, I added and wired up the ESP32. I only half understand how exactly the RGB565 works. I'll delve deeper into the programming, but I understand that each color has multiple data streams to display more colors. I connected a UART header and the four remaining GPIOs to a pin header so I can use other devices later.

Finally, everything is tidied up and properly labeled, and we're finished with the schematic! Tomorrow is Christmas, and I don't want to sit in my room working then, but I'll start routing the day after!

Story + Idea

A few months ago, I wrote a program for homemade cameras using the NDI SDK to send video in real time and manage and stream it from a central location.

The software is mostly finished. There's a program for the cameras and a Flutter app for controlling them, compatible with all common devices. Now, I want to build a small, tablet-like device solely for controlling and configuring the cameras and devices on the Arenacast network.

I found this LCD panel on AliExpress. The description mentions the ILI6122 chip/driver for the display, which, based on my research and the assumption that the ribbon cable has 40 pins, points to an RGB565 interface. I'm trusting the datasheets and results provided by GitHub Copilot and using an ESP32 S3 WROOM2 to ensure not only the display interface but also a connector for the standard I2C touch panel connection. This way, I can figure out the graphical stuff later when programming. As far as I know, there's even a library for the ESP32 specifically for using these kinds of displays.

Let's get started!