Saturday, May 16, 2015

HDMI cables are NOT all the same!

Sometimes very cheap or thin HDMI cables do not work with the Raspberry Pi Camera extension kit I made. Even if a camera is correctly plugged at startup, the Rpi cannot detect the camera and output an error message. In this short post I will explain why and show a quick fix.

First a normal HDMI cable with 19 lines. This is the most common design. There are four data buses (one is hidden behind in the pictures) with 3 cables in each, a GND line and a GND shield. The HDMI connectors are also put to GND. The Raspberry Pi Camera extension kit works with this kind of cable.


Now, this is a smaller diameter (it was Micro HDMI before I cut it) cable with only 15 threads. This cable has 5 data shields but there are no GND lines in them! There is not GND shield, just a wrapping that was cut before taking the picture. The HDMI connectors are put to GND. This cable does not work out of the box with the Raspberry Pi Camera extension kit.

The trick to make the second cable work with the kit is to connect with a short piece of wire and solder the GND on the PCB and the HDMI connector. Of course this must be done on both sides of the cable. Et voila!
Even if there are no data shields, the quality of the image from the camera does not seem to be affected.



 If at this stage if there is no image from the camera it is time to ask me an exchange.

Note that I could have connected the HDMI connector to GND by default, I decided against this. For safety reason I try to avoid connected metallic parts floating around.  

37 comments:

  1. Hi, great product. Just wondered if there was an enclosure for the rpi with twin hdmi ports?
    cheers
    Phil

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  2. Yes on both connectors to connect their ground pins.

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  3. I still can't get mine to work. I've got three different HDMI leads and brought three pairs of the HDMI extenders. Testing with a multimeter it appears that connector 14 on the ribbon cable (SDA0) is not connected at the other end. Any tips?

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  4. I tried this, but it turns out in my HDMI leads even the metal plug cases are not connected!
    I had CSI pins 1,4,7,10 (Grounds) and 14 (I2C data) unconnected.
    My fix is detailed at https://www.john.geek.nz/2015/07/petit-studio-raspberry-pi-hdmi-extender-cheap-cable-fix/

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    Replies
    1. Awesome and fun writeup on that page. Recommend for anyone working with these to go read John's work on the cables.

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  5. Did anyone succeed using a 'cheap' 5m *flat-styled* HDMI cable? If so, which one? A short round cable (1.5m) works properly, but the 5m of http://www.aliexpress.com/snapshot/6933422178.html does not work, even after re-routing pin 14 to signal path to pin 'A' (because 14 was not connected). Shielding & all relevant pins are properly connected with this mod, but signal integrity seems insufficient (led on camera remains on though). Ferrite cores don't make any difference...
    I really could use a working 5m (white) HDMI cable, preferably flat(!), so it would be great to have some reference of any success stories.

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    Replies
    1. I'm using the Adafruit DIY flat cables. They don't work either - how are they different?

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  6. Great to have a link to good cables as well

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  7. If HDMI cables costs a few more dollars it doesn't matter as along as they work properly i have seen couple of good hdmi cables at cheaper price HDMI Cable NT

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  8. yes by looking at the clarity of the screen we get to know the HDMI Cable quality whether it's good or best and now a days we can find cheap quality cables at cheap prices under any online websites like <a href="http://latestone.com/>latestone</a> still better to have proper warranty attached

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  9. I am in Kolkata, India, where even a good quality HDMI cable is rare. I got your extension boards and tried three different HDMI cables. None worked. I tried to check continuity and found pins 13 and 14 shows open through the HDMI cable. Can you share the Name of a working Cable, so that I can order that from ebay or amazon. Thanks

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  10. It would be awesome to have a list of HDMI cables that work, or some kind of identifier for the good ones. Thanks!

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  11. My Experience with some eBay HDMI Cables...
    This one works fine ... http://www.ebay.de/itm/251772881370
    And this is a Trouble cable ... http://www.ebay.de/itm/141346673708

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  12. Hello, I followed above blogpost as my camera wasnt working with HDMI cable. Still I face following issue..
    mmal: No data received from sensor. Check all connections, including the Sunny one on the camera board
    ..I used jumperwire for now to connect the ground

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  13. The "multimedia" in HDMI includes audio and visual, whereas DVI only includes video. Additionally, HDMI is by definition "high definition" graphics only, whereas DVI is anything involving digital graphics, which includes high definition as well as low definition graphics. DVI includes all images created via the display of pixels, or non analog video. So, though all HDMI is digital video, or DVI, not all DVI is HDMI. HDMI offers superior, higher resolution graphics displays. DVI includes the universe of digital video displays, high and low.
    http://www.latestone.com/eCommerceCategoryList?productCategoryId=1501

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  14. Really effective post for electronic knowledge i am really happy after read this post.

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  15. HDMI cables connect todays TVs with A/V receivers, cable boxes, media players, and Blu-ray players. They send audio and video over the same cable, simplifying your hookups.Choosing the right HDMI cables can be tricky. Older cables don't support the latest features. The latest HDMI 2.0 cables support 4K TV and HDR (High Dynamic Range).http://www.latestone.com/cables

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  16. I get asked a lot; What makes some HDMI cables more expensive than others? The answer to that question is that it is all about the quality of the materials used and the skill that is used to construct the cable. There is probably no better way to explain what makes the difference between a good HDMI cable and a poor HDMI cable than to deconstruct one of the HDMI Systems HDMI cables.

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  17. I am really impressed after read this post because that's helpful for adapters.

    15A to 20A adapter

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  18. howdy, your websites are really good. I appreciate your work.
    Kabel HDMI

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  19. Very informative post, thanks for sharing.
    http://bluefield.com.tw/product/hdmi-to-hdmi-10m-cable-bf116240456/#comment-5640

    ReplyDelete
  20. This comment has been removed by the author.

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  21. Bought a few of your kits, great work. Can you me what you do with the rpi end of the extender to secure it mechanically? I custom designed some laser cut cases for the camera end, but am at a bit of a loss as to how to secure the rpi end and make the hdmi accessible without a lot more design work.

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  22. hey there! Bought your connector and got it working with a normal HDMI cable. I tried the DIY adafruit cable then (https://www.adafruit.com/product/3564) but it doenst work. Even with the GND connected. Am I missing something?

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  23. like the solder pads on the V2 board, nice touch

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  28. This was not my related topic but the way you explained really great. and today through your post i got to know something out of my box. Thanks for sharing.
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  30. Could you use HDMI Over Ethernet Adapter then make the cable up?

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  31. hey can you suggest me where can i buy best hdmi cable very affordable prices

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