Worklog [2024 Contest Entry] The Xela - An RK3588S Powered Handheld

[AlexGorby]

Hi all,

During the summer of 2022, I made my own, fully custom emulation handheld based on the raspberry pi 4. That project pushed my limits on my 3D modeling, engineering and general design skills. At the end of it I had a working portable... and it was pretty terrible. Maybe I'm being a little hard on myself here, but there were just a LOT of these little issues that made the experience of using it kind of terrible. Buttons wouldn't register unless pressed just right, I could only squeeze in mono audio with no headphone jack, I had absolutely NO way to determine battery percentage and the handheld would just die without warning, ergonomics left a lot to be desired and so on.

This project aims to be my Pi Handhelds bigger, cooler, and all around more successful younger brother.

At the heart of this project will be an Orange Pi 5, this SBC has some insane emulation power and should be able to run GameCube, Wii and PS2 with minimal compromises (Maybe some light-weight Switch Emulation?). The board will be running Android 12, allowing for access to the latest and greatest emulators as they hit the platform, as well as Google Play Services.

As for the rest of the feature list, I plan to do the following:

• 7 inch, IPS Display at 1024x600, with Capacitive Touch
• 8000 mAh Battery (Should give me plenty of playtime on a single charge)
• Active Cooling
• Stereo Speakers
• Full 16 button custom Controller with dual full size analog sticks
• Battery management system for displaying battery charge and low battery signal.
• USB C PD Charging
• Stylish, ergonomic case
• Emulation Station Front end for a super polished User Experience
• Bluetooth & Wifi Support: Audio + Controller support
• Other cool things as I think of them

I've dubbed this handheld the Xela (bc I'm very creative and can spell my name backwards) I'm still not 100% sold on this name, so it may change before this project is complete.

 

[StonedEdge]

Best of luck! Sounds like a cool project

 

[AlexGorby]

Hey everyone,

I have a lot of updates to share for this project, like a LOT of updates. I should’ve done a better job updating the worklog publicly as the project progressed, but oh well, we’ll get ‘em next year. I still have plenty of pictures and info to share.

This project absolutely drove me to my limits with my understanding of electronics, especially with battery power and all things related to it. I’ll walk through the design of this handheld issue by issue to give you all the full picture.

As I said in my original post, this was not my first time making an emulation handheld. I had some experience on a project I did in 2022 with the Raspberry Pi 4. My largest gripe with that handheld was that it didn’t feel great to hold in the hands, making play sessions longer than like ten minutes noticeably uncomfortable. This was an issue I desperately wanted to avoid on this project, so I perused Wesk’s scan repo to look for something a little more ergonomic to base my design off of.

The Duke is a controller will live on forever in my mind as the controller that’s just way too big for its own good. However, that controller has a certain amount of charm (and heavy personal nostalgia) and it inspired me to maybe make an ashida type emulation handheld with the Duke.

I gave up on that dream almost immediately as I was designing it. Despite how much I wanted it to be an ergonomic handheld, I also wanted it to be a bit more portable than a cinder block. This design would also compromise my screen size... in case I needed another reason to abandon it.

I decided once again to go with a design more akin to the horizontal GBA

Here's a wireframe of the design I ended up with.

Now that I had my general form factor figured out, I could start ordering parts and start progressing on this project.


The Screen I ordered from Ali-Express was honestly gorgeous. Thin bezels, mounting points for the Orange Pi 5, Super vibrant colors, and a single ribbon cable as its connection made this perfect for what I needed. Except- It needed its own specialized android build in order to function correctly. Sure, that’s fine. I’ll load it up onto a 256GB micro sd card and start working on it. Nope. For some ungodly reason, the image wouldn’t boot on any micro sd card larger than 64GB. Super annoying, but I can work around it. I’ll have the USB 3 port accessible from the outside of the case and run games off that.

First time with screen in action, running Mario Sunshine on Dolphin

The Orange Pi 5 also features an M.2 slot on its back that would be perfect for an OS, but this is occupied by my Wi-Fi / Bluetooth module :/

I also found out a bit late in the design process (when I was waiting for the screen to arrive) that the screen was upside down to what I initially thought it would be. The ‘chin’ of the screen was at the top instead of the bottom. Again, a little annoying but I redesigned the case for a better fit.

Gorgeous Test Print:

I’ll breeze by the controller design pretty fast as the PCBs I needed made weren’t all that complicated. The Arduino micro would do all the heavy lifting using an xinput library. Basically I needed to have 4 pcbs made, as the face buttons and joysticks sit on separate planes to accommodate the full analog stick size. i had these ordered from JLCPCB and they game out fantastic!

Looking back, these could’ve seriously benefitted from some ribbon cables… I’ll maybe clean that up in a V2 of this project.

Power was my final and most difficult challenge of this project. Finding a power source that could both provide a solid 5v at 3A+ while fitting within my desired form factor was exhausting. I found a small pcb on ali-express that supported both PD fast charging, and the needed 15w+. I connected power via the GPIO headers on the Orange Pi. And for reasons I couldn’t pinpoint at the time, things were going wrong. The screen would sometimes register touch inputs that weren’t there and eventually stop working entirely. My analog joystick inputs would flicker down and left. Everything wasn’t working as it was supposed to, which was very frustrating this late into the process. I tried three different power boards, all were too big for my form factor AND didn’t resolve these issues.

I put this project on the backburner for probably 3 weeks before I picked it back up again. Then, for no reason in particular, I soldered the power wires directly to the GPIO headers.

It worked. Everything worked. The screen stopped flickering, the handheld stopped crashing, the controls were solid.

It was time for the final assembly.

Here are some juicy pics of the internals during assembly of the portable.

And here is the final result!

My Submission Video: (which contains a bit more info about some of these components, as well as some rambling about my previous handheld.)


**EDIT: I failed to mention this in both the video and this post, but battery life is around 3.5 - 4hrs when pushed (PS2 at a 2x Upscale), and around 6+hrs on lighter emulation (SNES)

All in all, VERY happy with how this project turned out.

I can't wait to see what the rest of the community has come up with! Good Luck with submissions, everyone!

 

[Stitches]

Great work!

 

[StonedEdge]

Looks great! A bit thick - but without removing the ports or designing custom PCBs, I think its hard to achieve a thin form factor. Really nice build

 

[AlexGorby]

Thank you!
True, its about as thick as a Wii U gamepad (when measured from the back grips to the faceplate) but it gave me plenty of space for a large battery

 

[Stitches]

But is the battery also the heatsink?

 

[AlexGorby]

I've got a couple heatsinks mounted on the Pi itself. The 30mm fan pushes enough air to keep it relatively cool (~65 - 70°C under heaviest load) So I'm hoping that the battery isn't absorbing too much heat... I have yet to even feel that side of the portable get warm to the touch!

Banking on the cooling system and the distance between the battery and heat to prevent it from becoming a heatsink lol

 

[Stitches]

Sorry, inside joke for the old people. The cooling looks good

 

[Luke]

Love it.

Mind sharing info on the battery + PCB you used?

 

[AlexGorby]

Of course! Inside is a 126090 Lipo Battery, 3.7V with 8000mAh that I got from amazon. I briefly tried 3 18650's but they were far too thick to fit into the form factor I wanted.

The PCB I ended up using for power was a powerbank PCB off ali-express. I don't think I can give an exact name, but ill provide the link to it here.
It was super small, but it was powerful enough to do what I wanted to with it.

In a perfect world I would've designed my own PCB to handle this, but that's a bit above my pay grade at the moment.

 

[RegDogg]

Of course! Inside is a 126090 Lipo Battery, 3.7V with 8000mAh that I got from amazon. I briefly tried 3 18650's but they were far too thick to fit into the form factor I wanted.

The PCB I ended up using for power was a powerbank PCB off ali-express. I don't think I can give an exact name, but ill provide the link to it here.
It was super small, but it was powerful enough to do what I wanted to with it.
View attachment 35997
In a perfect world I would've designed my own PCB to handle this, but that's a bit above my pay grade at the moment.

ngl agreed, LiPos are one of the best performing small form factor lithium batteries there are, hence why they are used in Radio Controlled vehicles, laptops, phones, etc.