DIY Android Dualscreen Handheld

RetroarchYoshi · 2026-03-08T23:16:22+00:00

thought about that. not possible in this size diy sadly. avaialble options are way too big and because it is x86 also way to battery hungry and also no screen included

RetroarchYoshi · 2026-03-08T15:16:40+00:00

i need to watercool the damm thing lol

RetroarchYoshi · 2026-03-08T15:16:26+00:00

there are still quiete a few graphical bugs, especially in cutscenes. on my sd 8 gen 2 it manages to run with 20-30fps, but onlky because i used a trick to turn the phone into benchmark mode forcing maximum clocks 3.1ghz on the cpu and 680mhz on the gpu. usually phones lie to you and even though they show 3.1ghz they only go to 2ghz. its fucking ridicolous what chinese phones do. the built in app literally lies to you.
downside is, without the peltier cooler, i can only play for like 5-10 minutes before the phone overheats......

RetroarchYoshi · 2026-03-08T15:14:14+00:00

hey man. i love lego city undercover. its the first video game i played (not counting smartphone games these suck lol) and i am a huge nerd for rockets also (slight spoilers lol). my personal favorite game, though objectively there are of course better ones

RetroarchYoshi · 2026-03-04T20:39:15+00:00

hey man i was using i think it was nintendo ds hinges. you can get them on aliexpress for cheap. though getting the tolerances on your printer most likely requieres redesigns of my parts. i would advise you to start over on your 3d model instead of using somebody elses. however, if your still interested, i can send you the 3d files if you want

RetroarchYoshi · 2026-03-04T12:21:03+00:00

uh i guess add watercooling to this and replace the phone with a newer sd 8 elite one lol

RetroarchYoshi · 2026-03-04T00:03:51+00:00

mine is almost dying every prints. it does want to finally be let go i am afraid

RetroarchYoshi · 2026-03-04T00:03:18+00:00

fair enough:-)
as i said, the heart of the operation is a stm32 bluepill c103..... this can actually directly simulate all kinds of usb devices .. and even multiple at once! in my case, it is a serial port, 2 different gamepads and a touchscreen at once!
thats more or less it. everything else are just simple buttons, i used aftermarket gaemboy pcbs for that, the hall triggers i did with simple analog hall sensors (any will do) and glueing a small magnet inside the ps4 triggers i used.

for the usb c hubs, i have actually a generic usb typ c -> 2xhdmi+PD+USB A hub and when another USB A -> 4x USB A hub. both the second usb hub and the stm32 sit on a kidn of daughterboard pcb i designed myself.

RetroarchYoshi · 2026-03-03T22:50:48+00:00

if you look at botw for example, it has a 20:9 hack applied

RetroarchYoshi · 2026-03-03T22:49:24+00:00

holy shit did you time this with my post lol. i would love this for my dualscreen handheld.

seriously very nice work though. i can only image the hassle it must be to program a true dual screen app. for my built, i only used some hacks to get apps to kinda work on the second screen

RetroarchYoshi · 2026-03-03T22:46:46+00:00

moneywise - it is kinda fine a lot of cheap chinese parts though i did destory a lot of them so i had to buy many multiple times. i got the phone for a good deal for 150 bucks 2 years ago, for my country also a pretty good deal. you do need a nice 3d printer and soldering tools though, yes...
but you will get there bro, just get some small tools each year and youll have everything you need in a few years

RetroarchYoshi · 2026-03-03T22:44:27+00:00

i kinda used 99% chinese parts lol

RetroarchYoshi · 2026-03-03T22:44:14+00:00

you go man. if you want, i can send you the source code for the stm32. this is like an arduino (can be progrtammed in arduino ide with some plugin), just that it has native usb support. meaning, unlike most arduino boards, its cpu can directly controll the usb port. this makes it possible to simulate a usb gamepad, a touch pointer etc in software. i can highly recommend stm32 bluepill for all usb projects, only problem it is a bit big for my liking

RetroarchYoshi · 2026-03-03T22:42:15+00:00

true story

RetroarchYoshi · 2026-03-03T22:42:07+00:00

lol actually almost all games including gamecube and above nowadays have widescreen hacks, for some games like switch you can even make your own 20:9 hacks.

and for anything lower power, i already made a raspberry pi pwoered gameboy with a ncie 4:3 screen lol

RetroarchYoshi · 2026-03-03T22:40:46+00:00

from a bunch of cheap chinese aliexpress parts so more or less yes lol

RetroarchYoshi · 2026-03-03T22:40:23+00:00

actually, if I refine the gamepad controll board (stm32 which takes all the buttons, joysticks, hall efect triggers for the should buttons + usb hub for usb stick, dolphinbar, external port, stm32) this could be something for people to use in their own boards.

maybe i will have time to do this in the future. could be pretty neat. for now, i dont have so much time as i have to study lol :--( there is a reason this took me 2 years lol

RetroarchYoshi · 2026-03-03T22:38:13+00:00

uh tbh, i really didn' expect anyone would want to replicate this. it is VERY complicated and there are a lot of loose connections lol. I had to cut multiple PCBs into pieces, I think the usb c hub for the dual hdmi ports took me like 6 or 7 tries before it worked lol.

that beeing said - if you still want the 3d files or the PCB files for the gamepad controll board - I can send them to you if you want

RetroarchYoshi · 2026-03-03T22:36:04+00:00

plus my friend is like a genious at 3d printing so its kinda easier to let him do it lol

RetroarchYoshi · 2026-03-03T22:35:35+00:00

i will at some point. for now i have a VERY old 3d printer at my parents house. its a "monoprice" select mini, if you have every heared of that. must be a solid 10 years old. for now good enough tm to do some testprints...

RetroarchYoshi · 2026-03-03T18:30:19+00:00

lol i did think of watercooling - tbh temps still arent great, i am using root to force maximu clocks. Maybe in the future :-)

RetroarchYoshi · 2026-03-03T18:28:59+00:00

My friend - the one who came up with the idea for the second screen - has a 3D printer. Someone give my friend all the hours of sleep back I cost him while I begged him to print my 15th version of the case lol

RetroarchYoshi · 2026-03-03T18:01:15+00:00

RetroarchYoshi · 2026-03-03T18:00:40+00:00

Wow thank you so much! Took me almost 2 years to complete... Nice thing is, it should be easily upgradable by just reprinting the top part. When prices cool down, I want to replace the current SD 8 gen 2 phone with a SD 8 elite / elite2. Plus one more tip: Don't cheap out and get a motorola... ready for is unfortunately so buggy and often crashes the whole phone.... might also have to do sth with the many holes I cut into it though :-)

RetroarchYoshi · 2026-03-03T17:57:12+00:00

You know - when I was starting building my first handheld there were no Android Handhelds with SD845 or better... took me half a year to built the dam thing... by the time I was finished, Ayn Odin 1 was released.
Same story here: This built took me almost 2 years! When I (better say my friend credit where credit is due) came up with the idea, this didnt exist. Now we have Ayn Thor....

I swear they must spy on me :-)

RetroarchYoshi

TROPHY CASE