2

Issue

Pictured overhead projector setup does not work. #1 -> #2 -> #3 -> Phone. All cables are tested and work! The issue is the HDMI connection between cable #2 and #3.

With all other cables, the screen will automatically be displayed onto the projector screen. No extra work needed. With the pictured setup, the smartphone screen is not displayed onto the projector screen. What is the issue with the HDMI connection??

Current running theory

Cable #2 does not have enough power. How do the adapter power supplies work? I can connect power to the MHL adapter (#3), but that still does not work.

Background

We recently had to do presentations at work (school), but the administration only provided VGA means of hooking up to it. Mostly likely reason probably dealt with cost. Anyways, there are several teachers that have brand new Samsung Series 9 ultrabooks (or similar). You know, the ones without VGA support.

So I bought an adapter for those ultrabooks. Cable #5 in the picture below.

However, both my coworker and I have been wanting to just display our phone screens on the projector. This I knew would require some extra work.

What I have

enter image description here

  1. VGA cable to projector (cables go through the wall)
    • For laptops
  2. HDMI to VGA cable
    • For laptops
  3. MHL adapter
    • For 11-pin microUSB phones
  4. microHDMI to VGA cable
    • For ultrabooks
  5. 11-pin to 5-pin microUSB adapter
    • For older 5-pin microUSB phones)

Equipment

  1. Projectors
    • 1 projector with VGA and HDMI input (issue is coworkers forget to switch sources)
    • 1 projector with VGA only input
  2. I/O Outputs
    • 2 new Samsung ultrabooks w/o VGA or HDMI support
    • 1 ultrabook with VGA and HDMI support
    • several other laptops with at least VGA support
    • 1 tablet with 11-pin microUSB
    • at least 1 new phone with 11-pin microUSB
    • at least 1 old phone with 5-pin microUSB
    • at least 1 iPhone 5s

Tested

  1. VGA cable (#1) to laptop
    • Good
  2. VGA cable (#1) to HDMI adapter (#2) to laptop
    • Good
  3. VGA cable (#1) to microHDMI adapter (#5) to laptop
    • Good
  4. Projector to HDMI cable (not shown) to MHL adapter (#3) to Galaxy Note 3 smartphone
    • Good
  5. VGA cable (#1) to HDMI adapter (#2) to MHL adapter (#3) to Galaxy Note 3 smartphone
    • Does not work!!
  6. VGA cable (#1) to HDMI adapter (#2) to iPhone adaptor to iPhone 5s
    • Will buy and test cable after current issue

Extra Notes

  1. The 11-pin MHL adapter will not fit inside the 11-pin to 5-pin microUSB adapter so older phones can be displayed on the screen.
  2. Right now I don't have the iPhone adapter, but I want to get my current issue solved because I don't know if the issue is the cable #2's HDMI connector or not!!
    • After issue is fixed, I will look for a solution for the iPhone 5s
Improve this question
5
  • What about a cable that accomplishes this instead of a daisy-chain? You're likely running into signal loss with all those adapters...and microUSB doesn't output all that much power for video.
    – Nathan C
    Commented Aug 25, 2014 at 17:02
  • @NathanC I live in Korea, and that item does not ship here. I also cannot easily find obscure adapters here easily at all. That would mean I would have to buy another large adapter for just the HDMI-only laptops. I don't know what some of the laptops have (some might be HDMI-only)
    – Christopher Rucinski
    Commented Aug 25, 2014 at 17:11
  • I'm not sure enough for an actual answer, but from what I understand the MHL port powers that MHL -> HDMI adapter, but there's not enough power for the HDMI->VGA part which is failing to work. I've read that there exists HDMI->VGA adapters that come with power supplies (like for the Raspberry Pi), but finding them is another story.
    – Nathan C
    Commented Aug 25, 2014 at 17:17
  • @NathanC How does the power supplies work? I can hook up power to my MHL adapter, but that still does not work if I plug it in for power. If you are not sure, and you feel this question is good, then please upvote it
    – Christopher Rucinski
    Commented Aug 25, 2014 at 17:20
  • You could try and get an HDMI power injector. YMMV, though. There might be powered HDMI/VGA converters available, too.
    – Daniel B
    Commented Aug 25, 2014 at 18:41

1 Answer 1

Reset to default
3

You cannot do this using the cables you have available.

Both the MHL-to-HDMI and HDMI-to-VGA adaptor cables are "active converters". They have proper electronics built in to them and actively convert one signal type to another very different signal type.

Because they are active cables they both need a power supply.

The MHL cable has a power supply: your phone. This cable expects a self-powered HDMI device such as a computer monitor or TV and will not supply power because it would be complicated (internal phone electronics) to pump more power down that cable than is required to power a single USB device such as a memory stick or MHL adaptor.

The power for the MHL adaptor is to charge your phone, not to power the device attached to it.

The HDMI to VGA adaptor also requires a power supply, it is taking a pure digital signal and converting it to an analog one. It currently has no power supply and does not work.

Unless you either a) buy an MHL to VGA adaptor or b) somehow cludge a power giving HDMI-to-HDMI adaptor between those two cables, then what you are looking to do will never work.

You should use the right tools for the job rather than pounding a nail with an old shoe or glass bottle.

Improve this answer
6
  • Thanks a lot. I knew this was a cable issue, but thought that maybe there was an issue with pins not lining up (think cross-over vs. straight-through) with the HDMI connector. Do you think the MHL adapter's HDMI connector does not allow power? Even with the MHL hooked up to additional power? I am just trying to understand a field I am not too knowledgable in.
    – Christopher Rucinski
    Commented Aug 25, 2014 at 18:33
  • I think I can keep all my cables. I will take my Samsung MHL adapter back home for my TV, and see if I can find a 11-pin MHL to VGA adapter. It seems like your link is to a 5-pin adapter. Also, question, would a powered HDMI to HDMI adapter work? or would a powered VGA to VGA adapter work? Or would both of them power the VGA brick on the adapter? I will not do either way. Just interested.
    – Christopher Rucinski
    Commented Aug 25, 2014 at 18:38
  • Most modern systems try to avoid cable crossover wherever possible because it creates more headaches than it solves. I am 99% certain that all the pins will be direct pass-through as what you have is a HDMI-input-to-VGA-output adaptor which is the correct way around for what you want. Your cable states "No need extra Power, from HDMI Power" so you probably could get a cheap inline HDMI adaptor, cut it open and connect a 5V power supply to pin 18 and the shield and it would probably work (a VGA one wouldn't), but I wouldn't risk it. A proper adaptor really would be the safest bet.
    – Mokubai ♦
    Commented Aug 25, 2014 at 18:44
  • yes, and that is what I will be looking for now. FYI, I had completely forgot how the adapters actual work and that seemingly simple adapters like cable #2 would actually need power. Thought I was using a hammer for that nail, but I was actually holding a bottle. Thanks for turning on the light in the room so I could see
    – Christopher Rucinski
    Commented Aug 25, 2014 at 18:54
  • I'm glad you took it in the humour which it was intended, it is sometimes difficult, as they say, to see the forest for the trees when you're trying to get certain things to work and I was (hopefully) trying not to offend. I'm sorry it's not the answer you wanted though.
    – Mokubai ♦
    Commented Aug 25, 2014 at 19:07

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