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I'm looking at getting one of those small and cheap car monitor displays and having it as a second display for my laptop:

https://www.amazon.ca/Buyee-Inch-Monitor-Backup-Camera/dp/B00M6OE1PS/

Now being younger I get scared and confused when I see the yellow, white, and red wires.

So given that I'm using a generic Windows (10) laptop with HDMI output, how can I wire up this mini screen as a second display?

I'm down for buying any adapter cables or other electronics necessary to make this work.

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  • How many DVI and HDMI ports are available (both on the monitor and on the laptop)? – SpacePhoenix Mar 17 '20 at 7:18
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    Honestly, if I were you, I'd sort amazon.com/Monitors-25-50-Computers-Accessories/… by ascending price and browse it until you'll find something that fits your budget and has a more modern input. – Nzall Mar 17 '20 at 12:08
  • I'd recommend that you watch this video which is a guide to doing exactly what you want: youtu.be/CfirQC99xPc – Vinayak Mar 17 '20 at 22:01
  • The gist of it is that you can get a cheap panel from Amazon or AliExpress along with the control board for that panel. Then you can connect it to your laptop via HDMI and will probably need something to power the second screen as well. – Vinayak Mar 17 '20 at 22:03
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    Do you realise how small that screen is? Your phone probably has a bigger screen. What would be the usefulness of such a tiny screen, with its very low resolution, and probably terrible image quality? There's a good reason why it is that cheap... – jcaron Mar 18 '20 at 12:51
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Your monitor accepts a composite video input. This is an older analog standard that was pretty ubiquitous on TVs, VCRs, and DVD players in the late 80's and throughout the 90's, and is probably not as common as it once was. I'm not sure composite video output was ever common on laptops or graphics cards.

But there are dongles that convert from any video standard to any other video standard these days. And there is such a thing as an HDMI to Composite converter. Just enter "HDMI to Composite (RCA) Converter" in your favorite search and you'll see plenty of options. This is the first thing that came up in a search, but there's no model number or anything and I can't vouch for it. Just an example.

Note that you'll have really low quality with this, but it should be fine for watching video or possibly playing old games in emulators.

Why is composite low quality? Composite combines the color information and luminance (brightness or black-and-white) into a single signal, which has to be "extracted" by the other end. The color information distorts the luminance information, resulting in color fringes, colors that don't look good next to each other on the same line, and high-resolution black and white stuff like text smearing into color. The Wikipedia article on composite artifact colors explains.

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    eBay has them for a tenner. I still wouldn't. ;) – Tetsujin Mar 16 '20 at 18:41
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    Yeah, unless that car screen was extremely cheap or free I would go buy an actual monitor. – LawrenceC Mar 16 '20 at 18:42
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    Composite was a thing on the higher end but ancient cards, pretty sure I had it on an Nvidia TNT2 Ultra and a Geforce 2 Ultra, which had an S-Video/composite output. That was 20 years ago and I don't think I've seen once since. It was awful back then and compared to HDMI or any of the digital outputs composite is a horrifying mess. VGA is bad enough, but composite is eye-achingly bad. – Mokubai Mar 16 '20 at 22:35
  • I think the best thing to do is to get another panel with its control board and plug it into the HDMI port of the laptop. I don't think anyone wanting a second screen wants a low quality one – Vinayak Mar 17 '20 at 22:07
  • Thank you, this was actually helpful and responded directly to my question. Cheers. – JDS Mar 18 '20 at 5:18
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That's not what you would really define as a 'monitor'. It would best be described as a 'TV' without a tuner.
It takes composite video, which is a rare output from a computer these days.

As mentioned in comments, you can get an adaptor.

I'd save your money & get a second hand 'real' monitor instead. The picture quality on that screen will be poor, at best.

From the advert - the screen resolution is a meagre 480x272 - your laptop will be at least 1920x1080 I would think. That's not even old analog television quality, it's about half your old "big TV in the corner that took up half the room" quality.

Avoid this product. Please.

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  • That's true, however, there are Composite to HDMI adapters out there – ComputerUser121212 Mar 16 '20 at 18:33
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    @milo8505 - Maybe you mean HDMI to composite; the other way round would be less than useless. Add another tenner for that, you still have an utterly useless tiny fuzzy analog input screen for about the price of a second hand cheapo monitor. – Tetsujin Mar 16 '20 at 18:36
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    @milo8505 - the screen rez is so tiny it will just be a complete & utter waste of time & money ;-) – Tetsujin Mar 16 '20 at 19:33
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    @Tetsujin Composite to HDMI converters, though obviously not what's wanted here, are extremely useful for old computers, game consoles and and other hardware. (They are also complex and expensive if you want accurate emulation of what the old signal would look like on an old monitor.) – cjs Mar 18 '20 at 0:33
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    A TV without a tuner is pretty much the exact industry definition of a monitor. – hobbs Mar 18 '20 at 5:54
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From your question it seems like you're looking to add a second screen to your laptop and you haven't purchased the car panel yet. If that's the case, I'd recommend that you ditch that idea and rip apart an old/dead laptop that you already own and salvage the screen in it or you could buy a cheap panel from AliExpress or Amazon along with its control board.

The panel and control board is all you need (besides a power source) to be able to connect it to your laptop via the HDMI port. If you're into DIY, you can build this yourself. Take a look at this video by DIY Perks (linked below) which is a tutorial on doing exactly this. However, before you do this, I'd recommend looking up the price of a cheap 1080p external monitor with HDMI input.

If you find that the cost of an external monitor that you can buy off the shelf is just as much or less than the parts you'll have to buy/salvage to make your DIY second screen, there's no point in taking the trouble and you could just go buy an external monitor. However, if it's cost effective to build one yourself and you have the tools for a DIY project, go ahead and build one.

Here's the video I mentioned: Build a DIY screen out of recycled parts for cheap

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Check this example, which converts HDMI to RCA only:

https://www.amazon.com/dp/B074GL885Z/

enter image description here

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  • Note this adaptor requires USB for power as well. – Criggie Mar 17 '20 at 20:04

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