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I got these male connectors from a broken cable and some flat cables.

Can I make a short (10cm or less) male-male HDMI cable using this stuff without worries? If so, is there any kind of trick on wiring or can I just solder each pin from one connector to the same pin on the other side?

the parts

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This question came from our site for users and developers of hardware and software for Raspberry Pi.

  • \$\begingroup\$ Have you had a chance to go over any standards documentation yet? \$\endgroup\$ – Ignacio Vazquez-Abrams Nov 16 '16 at 1:35
  • \$\begingroup\$ that 227 page technical pdf? no, sorry. \$\endgroup\$ – Blamoo Nov 16 '16 at 2:14
  • \$\begingroup\$ Downvote for laziness. \$\endgroup\$ – Passerby Nov 16 '16 at 2:23
  • \$\begingroup\$ @Passerby thanks for your contribution to the thread. You know how to make someone feel welcome. \$\endgroup\$ – Blamoo Nov 16 '16 at 2:42
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    \$\begingroup\$ I'm skeptic it'll work well but.. why don't you just try it? Passerbys answer is as accurate as we can get without actually having built/tested one ourselves.. \$\endgroup\$ – Wesley Lee Nov 16 '16 at 3:33
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At 10cm or less, you will most probably get away with using straight wires instead of twisted pairs. Even at full HD, your pixel clock will be 165MHz at most (less than USB2.0), and I have seen flat cables used for USB at such lengths. Also, there are commercial HDMI cables which use flat ribbon at the last few centimeters to enable easy termination.

To maximize your chances, make sure that:

  • each differential pair runs on adjacent wires inside the ribbon cable
  • differential pairs are separated by at least one shield wire to reduce cross-talk

As a side note, there are longer DIY HDMI cables out there, but those are usually based on a CAT-5 Ethernet cable which provides twisted pairs with suitable characteristics.

I'd also like to reiterate my comment: there are short HDMI cables for under $1, so honestly, your time will better be spent elsewhere.

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Could you make the cable? Sure.

Would it work? Maybe.

Would it work well? Highly unlikely. You may get a signal but not high resolution bandwidth. Too much noise. Not enough twisted pair. Etc. The two ends will attempt to negotiate down the speed to what the cable supports.

That said, YouTube shows a ton of diy hdmi cables, so it's not a absolutely futile project.

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  • \$\begingroup\$ I'm gonna use it with a Raspberry pi mounted behind a small tv... It's a 1080p@60hz signal... \$\endgroup\$ – Blamoo Nov 16 '16 at 2:38
  • \$\begingroup\$ If your lucky the cable may get you 480i \$\endgroup\$ – Passerby Nov 16 '16 at 2:51
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    \$\begingroup\$ If the connection is resonably short (<20cm) and the soldering is well done, flat ribbon cable usually works fine. Adjacent conductors aren't that bad in relation to twisted pairs. \$\endgroup\$ – Janka Nov 16 '16 at 11:47
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I have tested this, because I needed a short and very flexible HDMI connection. The length of my ribbon cable is under 10cm using only 13 wires. The resolution i have tested is 1080p.

If you're fine with some pixels or sometimes horizontal lines caused from interferences, this solution totally works. At worst sometimes my monitor turned off for a second.

If you want to have better video quality wrap the ribbon cable in aluminium foil and secure (cover) it with electrical tape. I dont know how important it is, but I also soldered the aluminium foil to the shielding on both ends of the connectors.

This way at 1080p, I get a sharp signal to the monitor without noticing the slightest interference. As for soldering, 13 wires at pins 1,3,4,6,7,9,10,12,15,16,17,18,19 are enough for the connection to work properly. I initially used a smaller ribbon cable before (about half the thickness), that did'nt work out well. A ribbon cable about the thickness Blamoo showed in the question is enough for me.

If you need HDMI to mini HDMI you need to swap some pins, even if the pinout is (almost) the same. Be warned: if you do this wrong you might fry the connectors (happens to me)

Good luck.

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