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Re: Collecting information on alternative displays - please contribute
Posted: Wed Jul 05, 2017 7:07 am
by marketus
Does anyone know how to reduce brightness level on the screen? I reduce it to 0 through the display's button pcb but it still is too high to play at night. Also the battery will last more time, I think could be interesting. Any thoughts?
Re: Collecting information on alternative displays - please contribute
Posted: Wed Jul 05, 2017 1:07 pm
by RogerX
So I happen to have a number of 5v to 12v DC-DC step-up converters. Can someone smarter than me explain the pros/cons of using this to power the screen at the expected 12v, as opposed to modifying the screens?
I am assuming you'd be losing efficiency on the step-up and there's probably already a stepdown happening on the board, which is more loss?
Edited to add: I would be adding an extra component to the build, which is cumbersome enough already. But I guess my haziness comes from not knowing what the actual display board is doing from a voltage standpoint. Is it using 12v for certain components? Or is it blanket dumping the input down to 3.3v and/or 5v for the display logic and backlight/LCD? I think these DC-DC converters were like 94 cents each if you bought 10 of them.
Re: Collecting information on alternative displays - please contribute
Posted: Sat Jul 08, 2017 11:34 pm
by tinkerBOY
RogerX wrote: ↑Wed Jul 05, 2017 1:07 pm
So I happen to have a number of 5v to 12v DC-DC step-up converters. Can someone smarter than me explain the pros/cons of using this to power the screen at the expected 12v, as opposed to modifying the screens?
I am assuming you'd be losing efficiency on the step-up and there's probably already a stepdown happening on the board, which is more loss?
Edited to add: I would be adding an extra component to the build, which is cumbersome enough already. But I guess my haziness comes from not knowing what the actual display board is doing from a voltage standpoint. Is it using 12v for certain components? Or is it blanket dumping the input down to 3.3v and/or 5v for the display logic and backlight/LCD? I think these DC-DC converters were like 94 cents each if you bought 10 of them.
Yes more loss.
Most 3.5" car lcd screen takes 12v, turns it to 5v, then lastly turns it to 3.3v. This alone is already redundant.
Here's what happen if you use 5v to 12v:
5v ==> 12v ==> 5v ==> 3.3v
Which makes it even more redundant and you will have some wasted power from stepping up and down. The further the input and output apart the more power/current is needed.
Most just find where the 5v output on the board and connect the 5v power there. Why not just connect the 3.3v from the Pi to the 3.3v pin on the lcd board? Because the Pi is not recommended to give too much current from the 3.3v pin. Well what about a 3.3v regulator that takes 5v power and outputs 3.3v for the lcd to use? Well the lcd already has a 3.3v regulator.
Re: Collecting information on alternative displays - please contribute
Posted: Sat Jul 08, 2017 11:51 pm
by tinkerBOY
marketus wrote: ↑Wed Jul 05, 2017 7:07 am
Does anyone know how to reduce brightness level on the screen? I reduce it to 0 through the display's button pcb but it still is too high to play at night. Also the battery will last more time, I think could be interesting. Any thoughts?
I tried this on my BW screen with brightness reduced to 0% but still too bright when playing at night. I also noticed the power consumption is the same whether the brightness is at 0% or 100%.
Do you have a picture of your lcd board? Does the board use the AMT630 chip? Mine gets hot. How about yours?
- IMG_1416.JPG (1.36 MiB) Viewed 11406 times
Re: Collecting information on alternative displays - please contribute
Posted: Sun Jul 16, 2017 10:47 pm
by tinkerBOY
Has anyone tried this screen yet?
https://www.ebay.ph/itm/141031751479
Only $14
Re: Collecting information on alternative displays - please contribute
Posted: Wed Jul 19, 2017 9:50 am
by bouke
Found this screen today on Aliexpress, seems to be an updated version of the "Kedei" HDMI screen. Same resolution although this one specifically mentions it is IPS, maybe the other was TN? It also features buttons which can be used to access the screen menu.
Currently only 10 dollars, seems almost too good to be true but I guess I will find out.
https://nl.aliexpress.com/store/product ... 0.0.Ijt1R8
//Edit:
Price is now back up to 34 dollars but I guess they will have a sale again soon.
Re: Collecting information on alternative displays - please contribute
Posted: Mon Jul 24, 2017 4:25 am
by Renalti
bouke wrote: ↑Wed Jul 19, 2017 9:50 am
Found this screen today on Aliexpress, seems to be an updated version of the "Kedei" HDMI screen. Same resolution although this one specifically mentions it is IPS, maybe the other was TN? It also features buttons which can be used to access the screen menu.
Found
this one at only 17 EUR, it seems to be the same?
However, they wrote it only support Raspbian. Does it mean it won't work on RetroPi/RecalBox ? Why would I get
this one when for the same price I can have full HD and touch screen?
Could someone please explain to me, so that I don't order bad/incompatible screens?
Thank you all
Re: Collecting information on alternative displays - please contribute
Posted: Mon Jul 24, 2017 5:43 am
by tinkerBOY
Renalti wrote: ↑Mon Jul 24, 2017 4:25 am
bouke wrote: ↑Wed Jul 19, 2017 9:50 am
Found this screen today on Aliexpress, seems to be an updated version of the "Kedei" HDMI screen. Same resolution although this one specifically mentions it is IPS, maybe the other was TN? It also features buttons which can be used to access the screen menu.
Found
this one at only 17 EUR, it seems to be the same?
However, they wrote it only support Raspbian. Does it mean it won't work on RetroPi/RecalBox ? Why would I get
this one when for the same price I can have full HD and touch screen?
Could someone please explain to me, so that I don't order bad/incompatible screens?
Thank you all
I think both of the screens you linked are basically the same, both hdmi and have touch screen. About the price it's normal on aliexpress to find cheaper ones but expensive from different sellers. Its like direct factory selleres vs resellers.
Re: Collecting information on alternative displays - please contribute
Posted: Mon Jul 24, 2017 5:49 am
by tinkerBOY
zeroboy wrote: ↑Mon Jul 24, 2017 5:43 am
Renalti wrote: ↑Mon Jul 24, 2017 4:25 am
bouke wrote: ↑Wed Jul 19, 2017 9:50 am
Found this screen today on Aliexpress, seems to be an updated version of the "Kedei" HDMI screen. Same resolution although this one specifically mentions it is IPS, maybe the other was TN? It also features buttons which can be used to access the screen menu.
Found
this one at only 17 EUR, it seems to be the same?
However, they wrote it only support Raspbian. Does it mean it won't work on RetroPi/RecalBox ? Why would I get
this one when for the same price I can have full HD and touch screen?
Could someone please explain to me, so that I don't order bad/incompatible screens?
Thank you all
I think both of the screens you linked are basically the same, both hdmi and have touch screen. About the price it's normal on aliexpress to find cheaper ones but expensive from different sellers. Its like direct factory selleres vs resellers.
Oops sorry my mistake i opened the wrong link.
If you just want a simple setup get the composite screen. Otherwises get the hdmi which will probably give you a nicer image quality but needs some more work to put inside the GBZ.
Re: Collecting information on alternative displays - please contribute
Posted: Mon Jul 24, 2017 6:21 am
by Renalti
zeroboy wrote: ↑Mon Jul 24, 2017 5:49 am
Oops sorry my mistake i opened the wrong link.
If you just want a simple setup get the composite screen. Otherwises get the hdmi which will probably give you a nicer image quality but needs some more work to put inside the GBZ.
Thank you @zeroboy for the reply! I read somewhere on this topic that the linked "HD screens" where actually low-def converting to "fake" HD. Anyway, I'll still grab one, just for fun, and try it!
Thank you