image of my current laptop, the Dell XPS 17 9710.

2025-mar-04

finding the right components is hard.

what am I going to do about it?

an update on the laptop.

You may remember the last post I made about the laptop I was planning on building, using a Radxa CM5 and other hardware I'd try and make myself. Well, even though it's been three months, I can't say I've done much progress on it. Unfortunately, the time and budget constraints of being a college student have caught up to me, and I've had to put the project on pause very frequently. That doesn't mean I've been doing nothing, though; I have a tiny micro-update for you. First off, I think I've finalized the requirements. It needs to:

  • Have a battery capacity of at least 90 Wh.
  • Have a removeable/optional second battery to swap while it's running.
  • Have an HDMI-in port and a USB-out port for use as a monitor / keyboard for other computers.
  • Be able to be charged with 5v, 9v, 12v, 15v, or 20v.
  • Have Wi-Fi.
  • Have an OLED display that's at least 16".

I've also identified some nice-to haves:

  • PoE charging.
  • Ability to run in Tent Mode.
  • Ability to switch between having a Desktop Environment (I like KDE Plasma) and CLI-only mode (or maybe use dwm for window management?)

I also have some components in mind. The CPU is, of course, the Radxa CM5. For the battery, I'm thinking of using five MIKROE-4475 batteries in series, which would give me a total of 111 Wh, which I'll use with a buck converter based on the B560C to get the voltage down to 12v. As for charging, I found a special USB-PD trigger board that instead of just asking for 20v, it can negotiate for 5v, 9v, 12v, 15v, or 20v, and it will output the highest voltage supported. This, combined with a boost converter (I'm still looking for one efficient enough), will allow me to charge the batteries with any USB charger, but will prefer 20v whenever possible. As for that boost converter I mentioned earlier, I'll have to get a programmable load to test it, as I want to choose one with a high efficiency (not only to keep as much of the power as possible, but also to reduce the heat generated). I'm doing this because it's more efficient to buck the voltage from the batteries once efficiency actually matters (running on battery), than to have some of the batteries in series and have to use one boost converter for charging, and a second one to go from the batteries to the computer itself.

To have an HDMI-in port, I'm thinking of using a C790 HDMI to CSI adapter, which can take up to 1080p60, which is more than enough for my needs. I've already got an AX210 Wi-Fi card, which I'll use for Wi-Fi. Finally, I'm probably going for the ATNA60BX01 120Hz 3200x2000 OLED from the VivoBook Pro 16X, but Radxa's eDP docs are a bit lacking. I'll have to figure out how to connect it to the Radxa CM5, but I'm sure I'll manage somehow.

One last thing: Remember the glowing Apple logo from old MacBooks? I'm bringing it back. My school has a CNC that can cut aluminum, so I'll machine out a hexagon into the back of the screen, and fill it with AA3528VRVFS-A LEDs. They're 3.5x2.8mm violet LEDs. Since I plan for the bottom panel to be transparent, I'll cram a bunch of these into whatever PCB needs indicator lights as well.




One last last thing: I'm sure you've seen the anyon_e project ↗ already. For those who haven't, it's a laptop developed by a high school student using a RK3588 (just like the rCM5), with a 4K display, an NVMe SSD, and a removeable keyboard. It was released on the 22nd of January of this year. I'm not going to lie, I'm a bit jealous that he managed to finish his project before I did, but I'm also glad to know that the future of tech is in good hands with the new generations.