Ambilight clone uses video pass-through; needs no computer

To the best of our knowledge all of the Ambilight clones we’ve covered over the years have one thing in common. They need a computer to do the image processing. This one is different. The PCB seen on the left right is all you need for the video processing. The project is called SCIMO and is the handiwork of a hacker named [Keiang].

There are only few times that the DRM built into the HDMI standard has pissed us off. This is one of them. Because of HDCP and licensing issued revolving around HDMI [Keiang] didn’t use HDMI pass through. Instead he uses an HDMI to S-Video converter. This board acts as an S-Video pass through, analyzing the signal using an STM32 ARM chip before the video signal continues on to the television. It still produces a respectable picture, but wouldn’t it have been cleaner if he could have gone with the HDMI standard?

UPDATE: Thanks for the comments on this. It looks like the TV is getting an HDMI signal. The board is fed by the HDMI to S-Video converter which itself is getting HDMI in parallel with the television thanks to a splitter.

Where other examples use Boblight on a PC for processing this manages to do so as a standalone embedded system. It also offers quite a bit of flexibility when it comes to choosing the LEDs, supporting pixels that use DMX512, WS28xx, or TM18xx protocols.

51 thoughts on “Ambilight clone uses video pass-through; needs no computer

      1. Now that you mention it, in firefox you can actually change a setting to do spell-check on single line input boxes. (which is deemed annoying since those are often for names and e-mail and addresses and such which would not be in the dictionary, so it’s disabled by default.)
        Maybe other software also has that as a ‘hidden’ option.

    1. He actually does use an HDMI splitter. One side feeds the TV, one his Ambilight clone.
      The LED controller is the only thing that uses the S-Video, and that’s just because it’s far easier to process that than to break HDCP and tap the HDMI signal.

  1. So where exactly would you see the difference between HDMI and S-Video? IIRC this device doesn’t pass any video through; it just forks some off to drive the LEDs and nothing else.

    1. What exactly are you complaining about? as far as i know, pass through is just another way of splitting the signal to two ends…. but it’s a fancy, probably trade-marketed, name for a split (one goes to the receiver, the other goes to the TV, but all in one box)

  2. So is the PCB on the left for non standard hands?
    It uses a splitter or S-Video from the receiver, the write up gives the impression that you get S-Video from this to input into your TV.

  3. Ah, yeah, he’s not doing S-Video passthrough at all. There’s a diagram on the page that shows the video source going to an HDMI splitter. The TV is still getting HDMI, it’s just the ambient lighting board that’s getting S-Video. Could probably do something similar if your receiver has multiple outputs.

          1. Yep, though the 200 led limit might be a problem for me unless I can find it with less leds per meter. I have a 100″ Planar XScreen I would love to use it with. It is a projector screen that has a bezel like a lcd or plasma tv. It would be perfect to mount leds behind, but with that circumference I would need somewhere around 7 to 8 meters LED strip.

    1. No s-video pass through. Hackaday got that one wrong, it just takes a s-video signal and processes that. More than enough for the low resolution needed for the leds.

  4. I thought HDCP had been cracked as the master key went around in 2010. I guess this is murky waters as he’d be in legal trouble if he wanted to sell a device that disabled HDCP.
    But I see no mention of him selling the ambilight clone, so maybe he could skirt around it.

    1. I know its bad form commenting on your own comment…but bunnie did a talk about a man-in-the-middle attack on HDCP-secured links. He says that you can swap pixels out, but as there’s no decryption then its doesn’t come under DMCA (technically). I guess that to look at the pixels that were to be displayed would require decryption.

    2. no HaD had it wrong it uses NO passthrew and the picture on the screen is full HDMI … and no you cant REALLY just crack HDMI … well you CAN with expencive components but you also run the risk of being sued for posting such a thing in the public domain

    1. The only good this could come to is to do the opposite and keep the room light constant to kill the flashing of video that editors do to strobe viewers, which is proven harmful to children and sensitive viewers. For a night scene it would ramp down in a few seconds.

  5. You guys do know that some 1×2 HDMI splitters provide HDCP-free signals on their secondary port when connected to an HDCP compliant sink on their primary port, right? And, from what I understand, most 1×4 splitters provide an HDCP-free signal on(at least) the third and fourth port. I connected a Dell 22 inch LCD computer monitor with a DVI to HDMI cable to my DirecTv DVR, and got a protection message on the screen. I connected the Dell LCD to the fourth port of my 1×4 HDMI splitter, and got HD video from the DirecTv receiver through the DVI port on the same monitor.

  6. I think he can actually sell this without no legal implications, and I would buy 2 of them. He is realistically just using a down-converter, like a digital converter box, but uses a splitter not to reefed the TV rather feed the LED’s. The TV get’s un modified signals from the Set-Top Box, Cable Box, or DVD/Blu-Ray player and the S-Video signals are not being used to rip the content to an external Drive or illegally duplicate the content.
    IMOHO the use of LED’s to display the content, really is not doing anything illegal.
    I actually tried this out, my Dish(satellite tv) receiver has HDMI out, RCA out, and Component video out, I used an RCA to S-Video adapter to hook it up to my other tv, to see if I could watch both at the same time and it worked. So even if he sells a model that only uses S-Video Input I would still buy it. Or if he adds a S-Video bypass like if you did not have HDMI no need to convert just go straight input to s-video I think many will still be able to use it in other applications.
    Does anyone know if he has any plans to sell this?

  7. HDCP refers to high bandwidth content protection. By downsampling the image to about a quarter of the resolution, I highly doubt the content applies to HDCP rules.

    Now that being said, Kickstart this immediately. Look at the success of Lightpack and that’s PC/Android only. The number one comment was: “Does this work with a regular TV?”. Obvious answer no, but this is such an elegant solution. Just design the unit to include the HDMI-S-video converter and the signal processing all in one.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s