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All About Laptop Display Reuse

LVDS, eDP, connectors and controllers - let's learn it all

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Hobbyists have tons of laptop displays ("panels") handy, yet aren't equipped to reuse them. This project is a one-stop knowledge database that will get any hobbyist up to speed on how exactly you can reuse them and what makes them tick.

Let's talk:
- Laptop panel parameters - coatings, contrast, viewing angles, TN/IPS/etc,
- Connection types and interfacing - LVDS/eDP/TTL and what do they actually do?
- Connectors and pinouts - how to wire a LVDS cable
- How to securely mount a laptop panel?
- Touchscreens
- How to connect a random panel - 0% to 100%
- Mating laptop displays and SBCs, i.e. RPi
- Laptop displays and microcontrollers?
- Different PC connection types (VGA/DVI/HDMI/DP) and their benefits/drawbacks
- LVDS/eDP controller types - from cheap to expensive, + about controller ICs
- Embedding controllers in your project - power, space and interfacing
- Reprogramming and hacking controllers' firmware
- Cabling and noise
- Common faults

Pages:

- How to find info on your LCD panel?

- [WIP] Making use of an LVDS laptop panel

- Common LVDS laptop panel pinouts

- Common LVDS cables for controllers

- eDP controller boards

- MT6820-B board information

- MT6820 board checklist for no-image debugging

- Rewiring a MT6820 cable

- What's the deal with FIX-30P-D6 cables?

Demos:

- [WIP] Reusing an Acer Aspire 5100 LVDS cable

- [WIP] Reusing an Asus X200CA touchscreen

Why laptop displays?

Laptop displays are in this interesting niche where we could be using them so much more, if only we knew how. They're small, thin, featureful and portable - yet easy to get and cheap. They're way more powerful than small MCU-connectable SPI/I2C LCD screens, more lightweight and power-efficient than desktop LCD monitors, significantly cheaper than portable monitors... In fact, when you buy a portable monitor, what you get is essentially a laptop LCD with a controller board slapped on top of it, in a nice case and with a not-so-nice pricetag.

There's a lot of uses for laptop screens!

  • Workbench displays for testing and datasheets
  • Portable monitors for work on the go
  • Outdoor monitors for kiosk applications
  • Arcade machine displays
  • User interfaces for SBC-powered equipment (i.e. a home automation console)
  • DIY digital picture frames and smart mirrors
  • Server closet displays for debugging
  • Video walls
  • Art installations
  • ...

You might very well be unaware that you could really use a couple of small and cheap displays somewhere on your hacking journey! For instance, here's a "desk duty" laptop of mine I use for datasheets and movies every now and then, which came with a low-quality 1366x768 screen. Its usability was vastly improved by putting a decent MT6820-driven 1650x1050 screen in front of the original one and using that as the main screen:

It seems obvious that we should be able to give any old laptop display a new lease of life. However, sadly, hobbyists do not know how to do that, and information available on the Internet often boils down to "just buy a pre-made controller". I aim to reach a point where you can pick up any LVDS/eDP screen and quickly read up on everything that makes it tick, even if nobody programmed a controller for it and put it up on eBay - and then be able to follow tutorial to get it up and running, whether it's with a converter board, or maybe your SBC's or motherboard's LVDS output, or maybe with the Raspberry Pi DPI interface!

Want to reuse your display?

Check out the "Pages" section above for information that could help you. Have some questions that these pages don't cover? Join our chatroom, or leave your question down in the comments section!

Want to help this project?

I could use help from:

  1. People making their displays work and documenting their journey here on Hackaday.io
  2. Contributors to this knowledge database
  3. Javascript developers interested in collaborate on writing an EDID library for an online EDID parser/generator
    • Click "Join this project" and let's talk about it!

Want to check out laptop display-based projects?

See this list where I collect such projects published on Hackaday.io!

hx6810.bin

MT6820 board firmware dump from the W25Q40.V 512KB SPI flash chip that's connected to the HX6810-A IC

octet-stream - 512.00 kB - 05/22/2021 at 10:29

Download

  • eDP controller boards

    Arsenijs07/25/2021 at 12:45 0 comments

    This is a list of eDP display controller boards, with their parameters and some notes on each specific board. More boards will be added as I buy and test them.

    a. HDMI-only board with flashable resolutions

    • Chip: RTD2556
    • Power input: 12V, 5.5-2.1 barrel jack
    • Audio: 3.5 output
    • Resolution: depends on firmware
    • eDP connector type: 30-pin

    These boards are typically available cheaply ($12/piece) with 1080p firmware flashed in.

    Read more »

  • [WIP] Demo - reusing an Asus X200CA touchscreen

    Arsenijs07/25/2021 at 08:46 0 comments

    I bought two of these touchscreens on eBay, complete with controller boards and frames. I had one 11.6" display available to me already, and another one wouldn't be too hard to source in the future if I decided to. But first, gotta successfully reuse one of these to make sure my idea works.

    [ TODO: pic ]

    This one is certainly a USB device - most of modern laptop touchscreens are - so most of the laptop webcam reuse tips will apply. I need to find VCC, D+, D- and GND. There's 4 pins on the connector, so I don't have to worry about pins like EN and RST being present - they are on some touchscreens, but not this one.

    The connector receptacle isn't something that I have a plug for when looking through my collection of random wire ends. This means I have to solder to the touchscreen board, sadly.

    Read more »

  • Project plans

    Arsenijs06/14/2021 at 11:57 0 comments

    I'm building this project as a knowledge database, complemented with a 0% to 100% guide for laptop display reuse. I want to take everything I know about this topic, lay it out somewhere, add new research where needed, and provide assistance to people in our project's chatroom. I'm also using this project to help me introspect and take notes on my own ability to follow the goals I set for myself - what helps me put ongoing effort into projects, when do I pause it, and once I do, how and when do I resume it?

    Over the next X months, I'll be adding information on topics I've already achieved things in during the past years:

    • CCFL inverter reuse (having reused multiple different inverters)
    • eDP screen reuse (in fact, I'm working on the LVDS articles first because it's more popular, but most of the screens I work with are eDP)
    • Laptop display assembly reuse (having reverse-engineered a display assembly for Lenovo Flex 2-14)
    • Touchscreen reuse (having built myself a touchscreen-equipped external monitor)
    • Triaging and quickly sorting through a large pile of laptop screens (as I have about 50 different ones from my laptop repair days)
    • Reusing screens with broken backlights and/or cracked LCD panels (for instance, I use the acrylic panels from laptop LCD backlights a lot in my projects).
    • Hacking the available controllers to achieve lower power consumption and better "sleep mode" abilities.

    I'd also like to work on the topics that I haven't yet worked on or that are more technical, like LVDS and eDP internals, term disambiguation, TTL to LVDS conversion nuances, different controllers' power requirements, managing high-speed LVDS/eDP interface and CCFL noise in your projects, and how to securely mount a laptop display so that its brittle parts are protected from the harsh reality of the outside world.

    Along the way, I will be assembling lists of information and projects, for instance, a list of all the commonly available LVDS and eDP controllers, their nuances and parameters, links to interesting projects where the "laptop LCD reuse" aspect really shines, others' blog posts with insights into i.e. the technical side of LVDS/eDP or other things I can't cover or won't have time to cover myself.

    One of my endgoals, apart from completing this knowledge database, is filming a video, about 10-20 minutes long: "How to reuse a laptop display - from start to finish". While I'll be working on guide articles, such as this WIP one, I can imagine a video reaching as many people as possible. This would be a decent way to help people understand the whole reuse thing, especially those people who are better at following videos than they are at following text guides.

    Read more »

  • MT6820 board checklist for no-image debugging

    Arsenijs06/14/2021 at 11:57 0 comments

    When it comes to reusing old laptop screens on a budget, MT6820 (also known as MT561) is a great board - for just $5, you get a VGA-capable board, a rewire-able cable and a button board. Here's more info on the MT6820 board, if you're curious.

    Let's assume you got one, followed the info available here (or somewhere else) to make it work, and it... doesn't. What do?

    Important note - this mainly talks about "no image"/"garbled image" scenarios, I'm not talking about "no backlight" scenarios, since backlight is usually taken care of by an inverter, an entity that has to be debugged separately.

    1. Check that the panel voltage is set up correctly (likely, to 3.3V)

    This kills the crab screen. If you've powered up your setup with the wrong voltage setting, the panel might be broken already. However, if you're sure your screen is 5V-powered, then it will require 5V to work and likely will not work with 3.3V. Having said that, overwhelming majority of laptop screens are 3.3V-powered.

    2. Is the keypad board plugged in correctly?

    Read more »

  • [WIP] Demo - reusing an Acer Aspire 5100 LVDS cable

    Arsenijs06/14/2021 at 09:01 1 comment

    Laptop displays in their natural habitat use different cables than the controller boards do. These cables are, of course, not designed to work with a MT6820 or a similar board, the cable usually has a proprietary connector of some kind on its end that needs to be snipped off and replaced with a 2mm pin socket that a MT6820 board could accept, or connected to a small adapter board and an appropriate receptacle. That sounds like quite a bit of work, but actually, these cables are quite nice and often worth reusing.

    1. These cables work with the original display assembly - they fit nicely through the holes in the hinges, so if you're rebuilding a laptop with a new motherboard (i.e. building a Pi-based laptop inside another laptop's shell), reusing the original cable is a decent idea if the controller-suitable cable is too bulky.
    2. These cables are often well-shielded and won't radiate or receive as much noise, which is good if you plan to use them near sensitive circuitry of some kind.
    3. In case of CCFL screens, these cables also carry the inverter connections and plug into the original inverter used, which means you don't need to solder wires to the inverter and can use the original connector.
    4. Sometimes, they carry USB signals on a separate pair of wires, that USB is typically used for a webcam or a touchscreen, and you can reuse these wires as you see fit
    5. These cables are flat, which is a bonus for sleek designs.

    The main problem, of course, is figuring out which wires on the proprietary end of the cable correspond to which connections. How do you do that?

    Read more »

  • LVDS cables for controllers

    Arsenijs05/29/2021 at 11:42 0 comments

    These are  cables that can be used together with universal and panel-specific controllers from China. If you have a suitable controller but the cable is not compatible with your screen's pinout, it won't work ;-( The headline is usable as a search term on eBay/Aliexpress/etc. so you can find a suitable listing.

    FIX-30P-D6

    A cable with the FI-X 30-pin connector that uses a single-llink 6-bit pinout - if you have a 1280x800 screen, this is what you'll be using, in all likelihood.

    Cable pinout


    FIX-30P-S6

    Read more »

  • What's the deal with FIX-30P-D6 cables?

    Arsenijs05/24/2021 at 12:52 0 comments

    I've previously mentioned that, funnily enough, single-link 30-pin CCFL-panel LVDS cables are commonly referred to as FIX-30P-D6, and dual-link cables for the same kind of panel are referred to as FIX-30P-S6. I've also mentioned that, in my experience, there's single-lane panels that don't work with dual-lane cables, with different results - from having no picture to showing rainbow colors, green-tinted screen or similar glitches. (My current theory is that some laptop panels short the unused pins for the extra LVDS lanes that the panel doesn't use, and this makes the MT6820 controller go haywire because its LVDS output pins are shorted to GND).

    I'm not even mentioning the fact that single-lane cables tend to be more expensive than dual-lane cables, even though they have less wires in them.

    All of that is nice to know.

    However, what the fuck does this thing mean?

    Read more »

  • [WIP] MT6820-B board information

    Arsenijs05/22/2021 at 04:38 0 comments

    Overview

    • VGA to LVDS converter with jumper-programmable resolution
    • Dual-lane and single-lane LVDS support
    • Has support for EN+ADJ inverter output
    • Has a pin header for wiring up VGA signals
    • 13 different resolutions supported:

    Resolutions (ranked according to subjective preferability ;-P), plus jumper combinations for different LVDS modes :

    Read more »

  • How to find info on your LCD panel?

    Arsenijs05/21/2021 at 16:49 1 comment

    Find the panel model number


    The most important step, arguably. It's going to be written on the back of the panel, on a sticker somewhere.

    Of course, there's all kinds of text on stickers on the back of the panel. The model number is going to be displayed prominently, but not always. Need some panel model number examples, as in, what kind of number are you looking for? Here's some:

    Read more »

  • [WIP] Making use of an LVDS laptop screen

    Arsenijs05/21/2021 at 11:44 0 comments

    ! These are LVDS screen guidelines! For eDP screens, I'll have a separate guide later on =) !~

    Fundamental ways to make use of a LVDS laptop screen

    1. Use a pre-configured and pre-wired "screen-specific" controller
      1. Should work out of the box - plug&play
      2. Might have multiple display inputs - in fact, there's a common board which has 3 separate inputs (VGA, DVI and HDMI), and they're all separate inputs you can switch between, effectively giving you a 3-input display for all of your tinkering needs!
      3. Most expensive option - in fact, prices vary wildly, you can be overpaying from $5 to $20 for a controller "programmed for" a screen that is not actually hard to program a controller for, -the eBay listing price can be increased because of the screen rarity or popularity, the firmware will be the same.
      4. Power requirements are prohibitive for portable projects - will typically need 12V, unless the board is tweaked for better power consumption
      5. These boards often use linear regulators heavily, so power consumption will be high and a lot of power will be wasted as heat, which is bad for battery-powered applications
      6. If there's only a "TV board" controller available, with antenna jack input and a USB port, these functions will consume extra power and might make your project's UX a bit worse
      7. Might have a speaker amplifier on it - if that's what you need, great, however, sometimes it'll just be another power-wasting addon
      8. CCFL inverters provided with these screens tend to be bulky, so harder to integrate in i.e. a laptop rebuild. It is likely that you'll be able to use the original inverter, though.
    Read more »

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Discussions

joeleaux wrote 07/01/2021 at 04:02 point

I have a particular display from a Polaroid DVD player/tablet (PDT9000). Pinouts have proven impossible to find. 

  Are you sure? yes | no

Arsenijs wrote 07/28/2021 at 09:59 point

Hey! Somehow Hackaday didn't notify me about this comment =( Without looking into it, I'd say, given its size, it's likely to be a TTL screen (~25 traces for the image alone) or a small LVDS one (should be 8 connections for the image, 4 differential pairs), but do join our chatroom and send us photos. What's  the model number of the screen itself?

  Are you sure? yes | no

joeleaux wrote 4 days ago point

The display has a decal:
H-M090Q-09Q
Barcode
M090WSBN40-AA-01  170323/002720

So, it could be this one:
https://www.aliexpress.com/item/32832757729.html

  Are you sure? yes | no

Arsenijs wrote 2 days ago point

I'm looking through Google search results and there's a pretty consistent presence of "AT070TN90" in those, which is something you can easily get a datasheet for: https://cdn-shop.adafruit.com/datasheets/AT070TN90.pdf I suggest you compare the pinout - make sure it's the same amount of pins, GND pins go to polygons on the FPC and connect to each other, R/G/B data pins all go to thin traces to the LCD controller silicon rectangle, NC pins stay NC (but some might not). If you send closeup photos of your display's flat cable end, I can help you check that.

  Are you sure? yes | no

joeleaux wrote 2 days ago point

how can i send the photos?

  Are you sure? yes | no

Arsenijs wrote 2 days ago point

Come here: https://hackaday.io/messages/room/297230 and send the pictures by using the "image" button or drag&drop

  Are you sure? yes | no

helge wrote 05/23/2021 at 10:01 point

I don't think collecting data in a chatroom is the right way to go. I mean, it's going to look good on your project if you come forth with a bunch of aggregated information, but I'm not sure how I feel about the format.

As a bit of constructive criticism, here's my take using a [179868] prefix for a HaD.io page:

https://hackaday.io/page/10753-179868-154-lgphilips-lp154w01

I disagree with the notion that we're contributing to a project here. I see making a particular panel work as individual projects attributed to the people taking it upon themselves to document their work.


The review and aggregation of the insights is separate from that and shouldn't be mingled with the rest. I think that's only one or two steps away from grabbing the info and stripping attribution.

Edit: right, becoming a contributor to the project is relevant for the competition aspect of it. Well, I'd rather stay away from that. Hobbyists that are in it for the competition have been nothing but trouble in my life so far.

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 10:35 point

>>> I don't think collecting data in a chatroom is the right way to go.

Oh, I don't think that a chatroom is a good place for data that has to stay accessible and searchable, either! Only mean that I've documented my own ways of "how I keep track of my laptop panel collection" - https://cdn.hackaday.io/images/original//8623601621649175483.png . What I have, however, is more personal than publishable, and it's more geared towards my own reuse effort in terms of its contents.

Your page is definitely a step in the right direction when it comes to the kind of plan we're discussing! Do keep in mind that the cable and the inverter are laptop-specific parts whereas the panel usually isn't, i.e. your panel has quite a few alternatives one could replace it with and still have it work perfectly in a laptop, but the cable and the inverter have specific pinouts, connectors and mechanical dimensions that just won't work on another laptop.

I've long planned to reuse some laptop-specific cables, however, and the next week I have a TODO task of reusing one - I'll be writing a short article about it eventually, and if you'd like to reuse this cable instead of i.e. rewiring an existing one, I hope my article will help you!

>>> I disagree with the notion that we're contributing to a project here.

Only if "technically" so, and only to the point where people can learn something about laptop display reuse intricacies from our conversation, which is no longer really about pinouts, but more about the logistics of information =) Other than this technicality, I concur!

>>> I see making a particular panel work as individual projects attributed to the people taking it upon themselves to document their work.

It certainly is an individual effort first and foremost! Due to the nature of how HaD project pages are managed, this isn't any kind of community wiki where everyone can edit pages and add their own pages, and I can't really hope to build a wiki like that at the moment, either, as much as a community-driven wiki might be more of a fitting format. I think of this project as of a knowledge database that enables people to do it quicker and cheaper, that I write based on my own experience,research and actions - it is my personal effort, others' efforts are projects on their own, and while I'll link to projects that people make so that people can learn from them, I certainly do not consider them part of this HaD project. It's one of the reasons why I keep a list of laptop display-related projects on HaD, people need to see what others do with their panels!

>>> The review and aggregation of the insights is separate from that and shouldn't be mingled with the rest. I think that's only one or two steps away from grabbing the info and stripping attribution.

"grabbing info and stripping attribution" sounds like something I'd very much like to avoid. Can you, please, expand on what is it you think I might be doing or planning wrong?

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 13:00 point

>>> right, becoming a contributor to the project is relevant for the competition aspect of it.
Funnily enough, the amount of contributors actually isn't relevant to chances of a project winning anything in Hackaday Prize, most projects I've seen win are one-man efforts. I've participated in previous Hackaday Prize challenges, and I'm pretty realistic about it - I've submitted this project to Hackaday Prize "displays" round, but nothing I do here is really "in the spirit" of projects that change the world, are commercializable easily or could benefit from a Design Lab residence. This page, realistically, has 0 chances of getting anywhere further than this round's final (which is a $500 prize), and even this chance is pretty slim, considering that, IIRC last time I checked, there's already 10 decent applications.

>>> Hobbyists that are in it for the competition

To put it explicitly, I'm treating this HaD prize round as more of "deadline for me to dump my brain and do as much research on laptop display stuff as possible + unlikely but plausible monetary reward for me to fund my crippling addiction to reusing laptop parts". Plus, there's the "positive coverage" part of that, which I've learned to be one of the most important parts - actually letting people know that this is a thing will seriously impact usefulness of what I make. After over a year of working with laptop displays specifically (and multiple years of hoping I get to do that someday), I can't help but feel like - now I owe it to people to tell every single thing I've learned. And, to be as frank and transparent as possible, the main competition here is between my lack of ability to finish projects I start and my desire to share what I've learned, as well as the desired ego boost of "I am doing a thing that people do really need" =)

One thing I do hope to be able to do, however, is eventually selling "making your display work" kits on Tindie which would cover usecases that Chinese sellers don't cover. For instance, eDP displays from laptops can easily be adapted to full-size DisplayPort with a small PCB that'd connect to commonly available eDP-FPC cables with standardized pinout, providing both a DisplayPort input and a small circuit generating EN+ADJ signals for the panel's builtin LED driver. Nobody is currently making these boards, but there's a market for them, and I will be making them. And I'll be linking to product pages for these boards from this project page, for sure - but that's not the end goal, it's merely "I can do this and it nets some extra income to fund my research" thing, especially given these boards will certainly be OSHW.

Other example - currently, a programming interface for M.NT68676 costs $25, but there doesn't seem to be anything to it that couldn't be replicated with a Raspberry Pi. When I get to reverse-engineering it, I'll certainly be making and selling small boards which'd plug into a VGA port of the M.NT68676 board, hook up to the programming interface pins (VGA SDA and SCL, but I do have to check that) and provide level shifting, if that's even necessary. However, as with all of the stuff I make and sell, it will be fully OSHW and anyone will likely be able to replicate that circuit using just a breadboard.

I have been doing projects online for a while now, and if there's a track record to what I do, it's "not finishing things", not "doing it for money/competition" =D This is, and always has been, my main challenge, and me participating in Hackaday Prize is mainly a tool for me to help provide some of the internal "drive" I'm missing.

And, to make it clear, I care about people's ethical concerns no less than I care about people's ability to reuse parts that'd otherwise end up in landfill - which is to say, I care about them a lot, as the amount of text I'm typing might indicate ;-P Please do check back as I go on and tell if you think this project is going in a direction you find undesirable - for me, it's a "openly accessible knowledge database" first and foremost, and if you think it deviates from this goal in a major way, I'd like to know about it.

  Are you sure? yes | no

helge wrote 05/23/2021 at 13:29 point

Thank you for elaborating. I think you understand my concerns, but rest assured that they are more a consequence of observing the shift in paradigms characteristic of the youtube content creator economy and the "maker" "community", where you support some random person in their hobby project quest, and before you know it you're expected to show the same kind of support and engagement and loyalty towards "oh yeah I decided to go all in and do this full-time now", and "support" has become "give me money and buy my stuff". I think it's abusive and should be discouraged.

So let's hope this is not that.


edit: strictly speaking, there would need to be criteria other than good faith that qualify a body of work as nonprofit. I'm not buying "it's open source" as a qualifying criterion on its own. If you've got exclusive production means or control the market (through brand recognition and access to the community, and thereby discouraging others from overcoming initial investment risks and NRE costs), that's as good a monopoly as there is.

I don't have a commercial interest in basically all projects I do, and I don't see why I shouldn't be allowed to surround  myself with people that are like-minded in that regard.

Idk, maybe I just need this pandemic to be over and have some quality time with friends at a hackerpace. I just don't trust people's intentions enough to go with a threshold assumption that they're idealistic as long as they stay below a certain amount of profit from their work.

  Are you sure? yes | no

dearuserhron wrote 05/23/2021 at 09:05 point

> Laptop displays and microcontrollers?

YES! Using avr attiny

https://github.com/ericwazhung/avr-lvds-lcd

https://sites.google.com/site/geekattempts/home-1/drive-an-old-laptop-display-from-an-avr

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 09:35 point

Definitely trying that out one day - I want to build an AVR clock using one of these!

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 11:50 point

BTW, that's a project by our own @esot.eric , even has a page here on HaD! #avr-lvds-lcd binary-clock  some good extra info and comments there =)

  Are you sure? yes | no

esot.eric wrote 05/23/2021 at 19:58 point

Thankya for the interest and shout-out @dearuserhron and @Arsenijs! There are a couple other wonky ideas in my various pages, too... e.g. using a Really Simple controller (just a few shift registers and a clock, no MCU!) to create a color filter for stage/spot lights, or maybe even a lamp shade... Some displays (especially DE-only which don't use H/V-sync) can (WAY out of spec) take in just a repeating pixel-value and try to display it, even lacking sync signals). That sorta hackery is very panel-specific, though, as again it's way out of specs.

Cool repository, @Arsenijs!

  Are you sure? yes | no

helge wrote 05/23/2021 at 08:34 point

There's something negative to be said as well though - this project may be cancer for the laptop repair surplus market. I was once lucky to find a spare display assembly for cheap when I needed it to fix my laptop.

Much like when TheSignalPath or EEVBlog release a video about that "bargain ebay find" lab equipment and how to repair them, they are effectively being removed from the market, because all it effectively does is create interest and competition, and I f* hate that.


So, it's a double-edged sword.

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 09:11 point

I see your point, I think there's definitely dangers, but I don't think it's going to play out the same way. Reusing display assemblies themselves isn't all that easy, as I've described in my previous reply to you - if there's any replacement parts that people will be incentivized to buy because of this knowledge database, it's laptop panels specifically, since that's what this project provides information on.

Out of all the things that a display assembly provides, you only really need the panel, but all those extra things (casing, hinges, webcam, cabling etc) make a display assembly cost significantly more than the panel, something that's basically a hard rule in the laptop display market - it's really not often that a display assembly costs less than the panel inside it does, and it's basically a guarantee otherwise.

This could apply less for touchscreen-equipped display assemblies. It's usually possible to buy a touchscreen+panel assembly, but less often so... Even then, however, the usual "reverse-engineering of the display assembly cables is hard" caveat applies.

I'd say, the biggest problem currently with finding assemblies is that they're a "value added" option. Most people, and certainly most repair shops are able to replace just what's broke - be it the display, touchscreen, hinges, cable, or whatever else. Even with glued together display assemblies becoming a norm, it's certainly a driver towards moving to assemblies, but people adapt to that and learn to deal with these, like I have learned to. And, in cases where an assembly breaks in a way that ppl are really incentivised to buy the entire assembly, i.e. hinges breaking and ruining the case or even touchscreen - especially if it's a factory defect that affects a lot of people (see also: every non-Thinkpad Lenovo from 2010 to this day) -, display assemblies are going to become expensive and rare purely because of the supply&demand law.

  Are you sure? yes | no

Arsenijs wrote 05/23/2021 at 09:20 point

I have an example in mind of what you're describing that's definitely possible, but is a long shot - people eventually figuring out a way to reuse some kind of interesting display assembly as-is, adapting the connectors and everything. It's not going to be "cancer" as such, but it might very well result in some assemblies being harder to buy - having said that, it shouldn't be much of a problem if the display assembly in question doesn't have some kind of family defect (*ahem* Lenovo *ahem*), since people will still be generally able to replace parts of the assembly when they break.

I know I've done some reverse-engineering work to try and reuse Lenovo Flex 2 14 assemblies, and a "assembly becomes rare because of hobbyists" scenario is possible if a certain assembly becomes popular as a result of someone's RE work, however, we're currently nowhere near the point where this'd be a thing affecting markets in a meaningful way. In fact, we're at a point where laptop displays are e-waste more often than not, and if certain parts become rare as a result of us moving away from that, we might even see the market react in a repair-friendly way. Having said that - is definitely a thing to keep in mind!

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helge wrote 05/23/2021 at 09:38 point

I appreciate that you took some time to reflect on the issue. Perhaps I have been on the receiving end of that equation more often than I'd like.


Hypothesizing that panels may outlive the hobby project they are being upcycled for, I would hope that the community is open to requests to "trade in" a sought-after panel for another one, even an off-the-shelf one currently in production, on a case-to-case basis.


I hope this won't be gamed by repair shops showing up as private people in need, but whom can one even trust today.

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Arsenijs wrote 05/23/2021 at 09:55 point

>>> Perhaps I have been on the receiving end of that equation more often than I'd like.

I have been too, and it's forced me to learn how to fix glued-in displays and crappy hinges, but it's nowhere near the effort I'd like to expend to keep my own laptop alive! And more often than not, hinge problems I encountered were also factory defects that a lot of people had, resulting in the display assembly prices going up specifically when I could use the whole assembly - so I feel your pain! I've ended up both having to learn new repair skills, as well as buying whole laptops (with i.e. motherboard issues) and harvesting them for parts in cases where the assembly wasn't salvageable.

>>> being open to requests to "trade in" a sought-after panel for another one

That'd be stellar to pull off! Shipping is probably going to be a bit of a problem - on the other hand, hopefully, people will be cataloguing panels they have (like I do, see: image in our public chatroom), and keeping their lists public... Maybe, I'll be able to impact the current "people have unused panels but nobody talks about it" situation, as much as it's status-quo-ey and comfortable - at the very least, I'll share my own best practices on "what to do if you have many panels, and ones you don't use".

>>> repair shops showing up as private people in need

In a way, repair shops are a proxy for private people in need! But I get what you mean, for sure, there's a lot of variables that can make things less-than-ethical, i.e. if they sell such a panel to their customer for the market cost of the sought-after one.

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helge wrote 05/23/2021 at 08:31 point

What a fun undertaking. As it seems, I've got at least 2 laptop panels sitting around, and I bought a VGA/DVI to lvds interface, but then decided it's too much hassle to figure out the connectors (Lenovo and Acer).

Seems like this project could turn "too much trouble to be worth it" into "hey, free display" for many people.

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Arsenijs wrote 05/23/2021 at 08:42 point

>>> turn "too much trouble to be worth it" into "hey, free display"

is exactly my intention with this project =)

>>> too much hassle to figure out the connectors (Lenovo and Acer)

You are talking about connectors for cables that come out of an laptop's display assembly, like this one?

https://cdn.hackaday.io/images//2153391621759640500.jpg

If so, they are indeed trouble to figure out - and I've tried! Thank you for a reminder, I should write a blog post about these! Apart from LVDS, they typically have inverter connections in them (for CCFL assemblies), touchscreen connections where applicable, sometimes even USB camera (often) and i.e. Bluetooth&LED pins (on Thinkpads), and every single one of these combined cables has a pinout that's tough to figure out; schematics help but only to a certain point, and wiring receptacles for these is also troublesome.

Instead, I highly suggest disassembling the display assembly and getting to the LCD panel itself. The connectors on the panels are very standardized by this point, there's basically 5 types of connectors+pinouts (3 LVDS and 2 eDP) that you'll encounter on the regular, it's highly unlikely that the one you'll encounter will be a unique one.

Thank you for reminding me about this factor! Goes on my TODO as a topic =)

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helge wrote 05/23/2021 at 09:06 point

Fyi the chatroom link above is broken.


The first panel I could find is an LG/Philips LP154W01

(ok WTF, HaD removes pictures attached to replies. Thanks for nothing, HaD.io)

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Arsenijs wrote 05/23/2021 at 09:31 point

>>> LG/Philips LP154W01

I have two of these! (sneaky edit: they're 1280x800 LVDS-1-6 panels with regular LVDS-1-6 30-pin connector pinout) They both work with an universal MT6820 controller and one of these cables: https://www.ebay.com/itm/142163214663 , plus a CCFL inverter, of course (mine are reused ones from laptops). I will be writing an article on reusing inverters soon - if you have laptop inverters already, then it'll cost you about $10 (inverter+cable) to turn one of these displays into a VGA display. Or even $6 if you rewire the default display cable that comes with the $6 controller, according to the MT6820 cable rewire guide I wrote, it takes about half an hour of work but that's it! And you can always opt for the ~$20 "panel-specific" controller =)

>>> broken link

Interesting, I checked all the links. They all take you to the same place that the "public chat" button in top left of the page, under the project name, takes you! Which is https://hackaday.io/messages/room/297230 . You can try to click the "public chat" button and that should work!

>>> removed pictures

Yep. Seeing how it's kinda possible to attach a picture to a comment, it seems to be a bug, someone should report it over at #Feedback - Hackaday.io 

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helge wrote 05/23/2021 at 10:26 point

Perhaps Hackaday should Rethink Rebuild Refresh their wysiwyg text editor. They haven't fixed other bugs for years. Placing and handling pictures is a huge pain for me. When I delete an empty line under a picture, it often deletes an entire paragraph above, pictures, text and all. Sometimes it jumps to the beginning of the page, sometimes it just fails to publish with an error.

I don't think we'll get to see improvements here, as it doesn't immediately create revenue for them.

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Arsenijs wrote 05/23/2021 at 10:43 point

>>> Perhaps Hackaday should Rethink Rebuild Refresh their wysiwyg text editor.

That would be great - I encounter quite a bit of problems while working with it, too! Usually, they're resolved by liberally pressing Ctrl+Z and trying to achieve my text editing goal with a slightly different sequence of keypresses (i.e. Backspace instead of Delete), if that fails, dropping into the HTML view and changing it up a bit so that i.e. a <h1> tag doesn't apply to a picture I just uploaded, or an entire block of text. I don't see it happening, however, seeing how this editor's misbehaviour has been a constant occurrence for years. I agree that it's no moneymaker, and I'd certainly also guess that, as with any platform, there's always more immediate tasks to work on and this just isn't high on the TODO list compared to i.e. immediate Hackaday Prize-related changes.

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Dan Maloney wrote 05/20/2021 at 21:52 point

This is a great resource! I've got a few displays around that I could reuse, nice to have all the info in one place. Thanks!

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Arsenijs wrote 05/21/2021 at 18:29 point

Thank you - hopefully the amount of things I want to list here won't be too overwhelming =)

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Starhawk wrote 05/19/2021 at 21:01 point

Inverter info is in the PDF datasheet I sent you, Sharp intended it to go with the panel! ;)

As also stated (albeit in a different place) -- the universal inverter i have is for another project and won't work here after all -- but I can scrounge one from another laptop. I also have one from a bad controller, that is an odd design that eBay doesn't seem to sell any more... photos in 30-60min or so when I get home. But maybe *it* will work.

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Arsenijs wrote 05/20/2021 at 16:49 point

Checked out the datasheet! Seems straightforward, actually - feed 12V on VIN and 5V on VBB&VBC to the inverter and set FPVEE to logic high, it should start at max brightness. Then, for brightness control, level shift your I2C to 5V, use I2C address 0x28, then write two 0x7f bytes to get medium brightness - is an inverted range, FF means minimum backlight and 00 means maximum, and you need to send the value twice because there's two "digital pots" to set it (for whatever reason - dual-lamp LCD?)

Sadly, doesn't seem to be a pin to signal a fault anywhere, lamps do burn out, after all - but it should work when you connect 12V and 5V, so you shouldn't need to fiddle with I2C for simple testing.

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Arsenijs wrote 05/19/2021 at 19:49 point

=== Question from @Ricardo on old project page: ===

This is interesting. I have a ltn154at07 screen from an HP laptop. It would be great to make it work with a RPi. It has a 20x2 connector for the video signals and power, two u.fl for wifi antennas and a usb for an integrated camera.

=== My answer: ===

If you have $20 to spare, then, assuming your panel's model is correct, this: https://www.ebay.com/itm/184478444884 would be your best bet! On a lower budget, it can also be done with a $4 VGA-only board, $3 VGA-HDMI dongle, reuse of the original CCFL and some cable rewiring - I'll do a tutorial on that eventually =) + I have an RPi HAT planned that'd allow you to direct-connect an LVDS display to GPIOs using DPI - hopefully I can get it to cost $5 or so, and it'll be the most energy-efficient option!

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Arsenijs wrote 05/19/2021 at 19:48 point

=== Question from @Starhawk on old project page: ===

I have an LQ141F1LH02 panel by Sharp, from a Pentium III Dell. This thing is... bizarre. I also have an MT561-B V2.1 Universal LCD Controller PCB. I'll PM you the datasheet for the panel and... what info I have on the controller PCB; you're welcome to add both as files to this Project.

Is there *any* way in H--- I can use that panel, with that controller? eBay doesn't have a specialized PCB for the panel itself. I'm not surprised... it's stupid crazy: dual LVDS clocks, an inverter with an I2C-like serial protocol to control it (I have a replacement inverter, too!) and so on. If it wasn't a 14in 1400x1050 panel, I'd not be bothered with it.

=== My answer: ===

14in 1400x1050? I respect that, a 1400x1050 14" panel was the very first panel I tried to make work, and also the first panel I made work! Well, I have 3 of those, and I did burn up the first one I tried to connect, by switching to 5V panel voltage accidentally, but the second one worked wonders =)

Yes, you should be able to use it! In fact, I am certain you will be able to! Dual LVDS clocks is exactly what you'd expect for a panel of such a resolution. I wrote a worklog on rewiring the stock "MT6820" board cable - it's designed for the desktop LCD monitor panels, not for laptop panels, these are 2 very different pinouts! I hope my tutorial explains it well enough - https://hackaday.io/project/166666/log/193018

You will want to take care of the inverter, first - you won't really know if your display's working fine until you get it backlit. It will also help you understand if, perhaps, the panel is cracked or the backlight is toast, which'd mean this panel might not be worth the trouble to begin with!

I usually deal with inverters that are controlled by two signals - "EN" and the "ADJ" PWM signal. I2C... I'd probably like to see more info about the inverter! I hope the inverter IC datasheet is available with all the I2C commands needed to make it work, that'd imply you can actually use it with a Pi (maybe with I2C level shifting if that one's 5V)... Are you sure it's I2C and not a slightly more convoluted EN+ADJ?

If you can't make an I2C inverter work, thankfully, EN+ADJ inverters are easy to get from old laptops, so you should be able to find a working one easily!

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