KeDei HDMI screen feels sluggish

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perseus404
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KeDei HDMI screen feels sluggish

Post by perseus404 » Wed Feb 06, 2019 3:50 am

Hi everyone :)

I have decided to build myself a Game Boy Zero and wanted to take this easy, step by step, so I first just ordered the HDMI screen from KeDei that some people are using and wanted to test it with my Pi 3 with a fresh install of the current RetroPie Image before starting with anything else.

In the RetroPie menu and running a rom (tried different) the movements feel very sluggish (think it describes it better than laggy). Hard to explain, but for example the slide animation when choosing a system in the RetroPie menu is slower than normal (compared to normal HDMI monitor attached to the same system) and the sidescrolling in the games (Snes Aladdin for example) lags minmal but noticeably (no smooth gaming).

Now, I have never used such a small screen and comparing the experience to a modern smartphone screen or any normal sized HDMI monitor is probably expecting too much of it.
So I wanted to ask here if somebody can give me some idea of what to expect from these screens. Is this small lagging normal or is this some setting issue/hardware issue in my case? Are composite screens better in that way (though less clear)?

Some troubleshooting I did was:
- hooking the Pi up to a normal HDMI monitor -> movements fast and smooth (so it must be the screen)
- powered the screen using its own micro usb port and with RPi 3 GPIO pins -> no difference
- used hdmi_boost=4 and disable_splash=1 in config.txt -> no difference
- hooked screen up to Windows PC (no native resolution possible) -> a video played fine, but mouse movement lagged

Settings in config.txt (rest is unchanged):

Code: Select all

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
hdmi_cvt 480 320 60 6 0 0 0
Thanks for your help :)

------------------------------
Edit: Screen Info
KeDei 3.5" HDMI in version 1.1 from 2018/5/8

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VeteranGamer
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Re: KeDei HDMI screen feels sluggish

Post by VeteranGamer » Wed Feb 06, 2019 4:38 am

perseus404 wrote:
Wed Feb 06, 2019 3:50 am

Code: Select all

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87
hdmi_cvt 480 320 60 6 0 0 0
Thanks for your help :)

------------------------------
Edit: Screen Info
KeDei 3.5" HDMI in version 1.1 from 2018/5/8


please upload a video of what you are calling sluggish....

especially as most people are using cheap and low power out putting PSU to power their builds.....

if your using a Powerboost 1000c or a Generic PSU
or a low powered USB cable
(i'm not suggesting that this is definitely the cause, but your not providing enough power)

then try using one of Helder Retro PSU
and maybe applying the power mod to the screen itself


also you kinda right... dont compare a $20 3.5" LCD to a normal HDMI monitor (have realistic expectation)




.





.

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tinkerBOY
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Re: KeDei HDMI screen feels sluggish

Post by tinkerBOY » Wed Feb 06, 2019 5:50 am

Yes it’s laggy but resolution is great. I still prefer DPI though.
Game Boy Zero Controllers available @ tinkerBOY.xyz
tinkerBOY Controller v3.0 - built-in usb controller, usb audio, and usb hub
tinkerBOY Controller v2.0 - GPIO buttons and builtin PWM Audio and Amplifier
tinkerBOY Controller v1.1 - simple pcb button
* DPI Adapter - better display for GBZ
* keyboard converters - IBM XT/AT Soarer's Converter | ADB to USB Converter

perseus404
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Re: KeDei HDMI screen feels sluggish

Post by perseus404 » Wed Feb 06, 2019 8:15 am

tinkerBOY wrote:
Wed Feb 06, 2019 5:50 am
Yes it’s laggy but resolution is great. I still prefer DPI though.
Thanks for the info, did not find that thread! :)
Might try DPI should I do a second build (improving on all the mistakes I am going to make in this one :D )
VeteranGamer wrote:
Wed Feb 06, 2019 4:38 am
please upload a video of what you are calling sluggish....
I uploaded one to youtube (had to play one- and left-handed) and tried to capture what I mean. Always hard with small lags, cause it is just subjective perception, maybe it is normal for these small LCD displays.
https://youtu.be/bj-iUDSLnG0

Regarding your suggestion with the power: I was planning on using the Powerboost 1000c, though for the time being the screen was drawing power from the Pi's GPIO header (case for the video). Pi was running on the foundation's original power adapter via micro USB.
I tested unplugging the screen from the header and connection via normal HDMI cable and powered it extra through its own micro USB port before and there was no difference. This time though i switched the power adapters and USB cables for screen and Pi (dont have that many) and I think there was a slight improvement. Also Pi was showing its undervoltage warning now so yeah guess the power input seems to be a problem. I will keep an eye on that Retro PSU, especially since i am thinking of going with the Pi 3 (already have a spare one) instead of a Zero..

What power mod are you referring to?
Edit: Found it here I think..

Thanks for the answers!
(now i will do some research on why low power input introduces lag to a LCD display ;) )

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correia5022
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Re: KeDei HDMI screen feels sluggish

Post by correia5022 » Wed Feb 06, 2019 4:27 pm

perseus404 wrote:
Wed Feb 06, 2019 8:15 am

I uploaded one to youtube (had to play one- and left-handed) and tried to capture what I mean. Always hard with small lags, cause it is just subjective perception, maybe it is normal for these small LCD displays.
https://youtu.be/bj-iUDSLnG0
Damn, thats really lagging. Guys is that normal??
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Re: KeDei HDMI screen feels sluggish

Post by infinitLoop » Wed Feb 06, 2019 5:11 pm

i just got one of these yesterday actually, but i hadn't planned on using it in a gameboy, since the reviews for using it for retropie are universally bad, and it's pretty hard to get it into a dmg case. i did just load up a retropie image on a pi3 as test after seeing that, but it's not nearly as bad as what's in your video. that's pretty gross. mine's actually not that bad - very playable I think. i know there are tons of variants of this model tho, and a lot of knock-offs too, so i'd imagine some are a bit better than others. not sure if it's something you can fix in the config. (i didn't tweak anything on this quick test)

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Re: KeDei HDMI screen feels sluggish

Post by perseus404 » Thu Feb 07, 2019 2:29 am

infinitLoop wrote:
Wed Feb 06, 2019 5:11 pm
i did just load up a retropie image on a pi3 as test after seeing that, but it's not nearly as bad as what's in your video. that's pretty gross. mine's actually not that bad - very playable I think.
Good to know that it is not normal that way.. what version and date was printed on yours? On mine it says v 1.1, 2018/5/8.
Also how did you power the screen in your quick test?

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Re: KeDei HDMI screen feels sluggish

Post by infinitLoop » Thu Feb 07, 2019 4:17 pm

perseus404 wrote:
Thu Feb 07, 2019 2:29 am

Good to know that it is not normal that way.. what version and date was printed on yours? On mine it says v 1.1, 2018/5/8.
Also how did you power the screen in your quick test?
i had the screen and the pi plugged into an external powerbank separately, and just connected via a short hdmi cable, not the gpio

mine is v1.1, 2018/5/8 as well, but i think i've seen people pry the board away to get a more accurate model number on there.

here's a short video - sorry its so shakey :(
IMG_5118.MOV
(3.33 MiB) Downloaded 32 times
and the back:
SpoilerShow
IMG_5119.jpg
IMG_5119.jpg (695.58 KiB) Viewed 644 times

here's genesis / sonic... but very hard to play with one hand, off-camera, on a keyboard :\
IMG_5122.MOV
(4.34 MiB) Downloaded 27 times

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Re: KeDei HDMI screen feels sluggish

Post by correia5022 » Fri Feb 08, 2019 7:26 am

infinitLoop wrote:
Thu Feb 07, 2019 4:17 pm

here's genesis / sonic... but very hard to play with one hand, off-camera, on a keyboard :\

IMG_5122.MOV
That's actually great quality...
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Re: KeDei HDMI screen feels sluggish

Post by perseus404 » Sat Feb 09, 2019 6:11 am

infinitLoop wrote:
Thu Feb 07, 2019 4:17 pm
i had the screen and the pi plugged into an external powerbank separately, and just connected via a short hdmi cable, not the gpio

mine is v1.1, 2018/5/8 as well, but i think i've seen people pry the board away to get a more accurate model number on there.

here's a short video - sorry its so shakey :(
Thanks for the videos! Performance looks way better than mine.. hmm.. I also tried with an external powerbank but did not achieve the same result.
I think I will return the screen and go for a composite one for my first build.. I rather have good performance and lower picture quality.
Also I am very certain I will one day do a second build to improve on several things, I will have a look at different screen solutions then again.

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