What components does one need to construct a functioning LCD?

Electronics
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Hi, Sorry if this isn’t the exact right category but this was the closest I could find.

I’ve been looking for cheap LCDs. First, I looked at old laptops. Then I looked at low end computer monitors and displays. Neither was a very good choice.

What about buying just an LCD panel from Alibaba? Has anyone does this? I get the impression that you buy the LCD panel itself and a controller for it. The controller is what the VGA/HDMI plugs into and also, I believe is what you use to turn the LCD panel off and on. Is that all you need to get it to work? Do you need a power supply or do those come with the controller? What do the number of pins on the panel’s connection means. For example, the fist link below has a 90 pin TFT connection.

  • 27" panel
  • 55" panel
  • not sure about which controller to use but it will only let me post two links anyways. my example would be a search for “lcd controller board tft 90 pin”
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I’ve fixed it so you can post more links now. (The link limit is an anti-spammer feature of Discourse. Sadly, we do have spammers showing up here and creating accounts to spam us, and if you never notice, you’re lucky. Spammers are why we can’t have nice things.)

Control boards appear to be available on ebay, as do some cables, but it’s not like the HDMI side with few options… There’s no trivial answer.

Looking at the 27" panel, I see:

Our company deal in all kinds size of Samsung/Sharp/ Mitsubishi /LG/AUO/CMO industrial LCD panel. We also can offer AD board, inverter, OSD key,Lvds cables etc for LCD panel.

So there, you could always ask them whether they can provide driver board and cables necessary for HDMI.

The part is listed as LM270WQ1-SLC2, so a search for LM270WQ1-SLC2 datasheet as several hits; looking at the first makes it clear that it uses two connectors for signalling:

connectors
connectors1090×404 50.6 KB

That gives you more search terms: S050-C51B-C39-A(UJU) FI-RE51HL IS050-C41B-C39-A(UJU) FI-RE41HL

The next page tells you about the backlight connector:

The LED interface connector is a model SM06B-SHJH(HF), wire-locking type manufactured by JST. The mating connector is a SHJP-06V-S(HF) or SHJP-06-A-K(HF) and Equivalent.

…and so forth; you would really want to look through the whole datasheet.

The second panel has more information called out:

el
el815×153 101 KB

But you would still want to look for the datasheet and read through it.

I don’t know how up to date it is, but it looks like someone has tried to collect some useful information at least a few years back:

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Whoa, thanks for the detailed reply. I’m new to Alibaba and it turns out people will list an incorrect price for an item and not tell you the real price until you request it directly. So it turns out the items I listed are so expensive that assembling the display myself would cost more money than buying a monitor and taking it apart. …I guess.

Boy this is frustrating. For example, that 27" panel is $215 an item. idk, maybe it’s $200 if you buy a hundred of them.

I’m not giving up on this idea just yet. Maybe Alibaba just has a spam problem or maybe all computer monitors are worth less than the sum of their parts. I’d like to take this farther if I can and provide a full explanation of what I discovered but that depends on whether or not I can find a reasonbly priced LCD panel. IMO a 27" LCD panel without controller, power supply, case, cables, etc. should cost like maybe $50? Right. Because I can go buy a 27" LCD on Amazon for $107.

I’ll report back if I figure any of this out. But if anyone knows anything about this I’d love to hear anything you have to say.

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What do you want to do with this panel?

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I was going to make magic mirrors with them. I think they’d sell for like $250 on etsy. So breaking down the cost of materials:

$30 lumber
$25 glass and reflective film
$35 raspberry pi
$10 paint/glue/stains
$20 cables and wires
$5 motion sensor
$10 SD Card

is $130 before you include the display. Now the good thing here is it’s pretty much the same price to make regardless of the display size.

I really am scratching my head here because it’s like monitors are selling for less than panels. There’s got to be a less expensive way to get cheap LCD panels than buying a cheap monitor and ripping the panel out.

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I would visit thrift stores and pick up old displays than add an HDMI controller (on amazon).
I frequent the thrift stores and see them all the time.
All in one computers are a good target for displays.
Were do you live. I have a number of old displays …

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They aren’t worth less than the sum of their parts, buying parts in single quantities is always more expensive than buying in bulk. If you were to buy enough parts to make 10000 monitors, you could get some substantial discounts. Economies of scale and all that.

1 Like
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I may go in that direction but I’ve been avoiding used displays for a few reasons:

  • I read something about they get less bright as they get older and brightness has a significant impact on the final look and feel of the mirror. To be clear, I’m not 100% certain about this. I still have a lot to learn about brightness over time and how it interacts with different reflective films.
  • Not having a consistent panel would lead to all kinds of problems. Some would accept different types of inputs so I’d need to figure all that out on a piece by piece basis which would take forever. Plus I’d have to make each case and two-way mirror differently.
  • I’d have to drive around to different thrift shops or craigslist sellers which will cost time and gas.
  • There’d probably be a few duds

I do appreciate the offer though.

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Why do you search on Alibaba? This is for manufactorers that need a lot of the same product.
Use Aliexpress if you only need a few. Also there you get the real selling prices (with or w/o shipping).

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Is there really that much of a difference? From what I’ve seen you might save 10% if you order a thousand vs one. That’s just what I’m seeing and interpreting though, I don’t really know.

I’m using Alibaba because that seemed like the right place to go to get LCD panels. It’s not really working though because they make it hard to find, say, ‘all 27" lcd panels less than $200 if you order at least 20’. Really, even just searching for “LCD panel” brings up mostly irrelevant results. It’s even worse on ebay because the vast majority of what I see there is replacement screens for phones.

I suspect the problem is just a lack of knowledge on my part which is why I originally asked this question. Maybe they aren’t called “LCD Panels”. Maybe there’s a better place to buy them. etc.

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often, when the answer don’t come easily that mean the search was not correctly asked.

a quick search from ebay show some 27" monitor for 139$ shipped, so with all the electronics modules requested included.

https://www.ebay.com/itm/BenQ-GL2760H-27-LED-LCD-Monitor-16-9-2-ms-BRAND-NEW-SEALED/254256055304?epid=219514184&hash=item3b32d78408:g:LkgAAOSwk2tcpQhr

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In a strange turn of events I ended up having to break down a monitor. It was already out of the case but the guts were still attached. I was finishing up my magic mirror when the carrier for the controller and power supply finally came undone. I could have undone it at any time but I didn’t realize it and also didn’t want to risk breaking anything. Anyways, so the answer just pretty much appeared in front of me. What my monitor is composed of is:

  1. The LCD panel
  2. The controller
  3. A power supply
  4. Possibly optional - buttons to turn the monitor on/off that plug into the controller

dFxE2me.jpg2592×2868

Now, here is the amazing thing. That display is from an acer 223w that I bought in 2009 for $130. The LCD panel used in that monitor is a Samsung LTM220M1-L01. Guess how much one of those panels costs today in 2019? Let’s say a minimum of $170 (1, 2, 3) and that’s just the panel.

@StephaneBUISSON, I know you can buy a monitor cheaper than the panel. That’s actually what I said in my second post on this thread. *I’m not attacking you I’m just trying to prevent this thread from going down that rabbit hole. Anyways, that’s what I find confusing. It appears that monitors are selling for less than cost of their components. Now, yeah, if you buy in bulk you can get a discount. But from what I can see, at least on Alibaba, buying any number of these panels does not explain this inequality. What I’m trying to say is even if I bought 100,000 LCD panels and turned them into monitors there still wouldn’t be a big enough of a discount to sell one of those monitors for less than the cost of a single LCD panel.

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Spare parts are sold from a different channel including it’s own stocks and managements. This is very different from monitor manufacturers buying from LCD factories channel which are not public.

My ebay link wasn’t a one off, several seller sale the same brand new product within few cts difference. That should gave you a good idea of the 27" market price you can get, in a positive spirit.

And I didn’t feel attacked, all good ! enjoy your project.

you can have a look here for some extra features : voice controlled Magic Mirror
and don’t forget to ask your mirror “who is the most beautiful ?” :rofl:

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