0

hi I just got a pi 2 model B but problem is I don't have a hdmi tv/monitor

so I was thinking of getting a hdmi to vga converter

I later found that it needs to be active i.e have its own power source

so I found this converter http://www.ebay.co.uk/itm/1080P-HDMI-to-VGA-M-F-Active-Adapter-for-Raspberry-Pi-Model-B-UK-/111343803449? which apparently is active but requires no external power source

do you think this will work with my raspberry pi 2

1

I have a VGA - HDMI converter that looks just like that one and works just fine, and it doesn't require external power. I think yours will work just fine. You might want to look around for one that has reviews on it if your feeling unsure.

Also, I don't believe that there is any special difference between an adapter for a Pi and an adapter for anything else. Also see this post. The opinions may be different than mine, but it will probably help you.

  • will it work straight away or do I need to edit things in the config file if so what do I need to do – user20151388 Oct 13 '15 at 20:56
  • I honestly have no clue. I don't use my adapter for a Pi, but I didn't have to make any changes to anything myself. It just worked. Actually, when I get access to my Pi, I'll try it myself. – Caleb Oct 13 '15 at 21:05
1

TL;DR - That cable is probably NOT HDMI compliant, but likely still works.

As you said, you do need an active converter to convert from HDMI to Analog (VGA). Analog signals are not provided by HDMI.

However, some cables (like the one you linked) do not have an external power source. If that's the case, then they are powering from the HDMI cable themselves. The HDMI spec says that you can draw at most 55mA, which I believe is far too little for a VGA converter. I suspect that cables like the one you linked are not HDMI-compliant, but still may work.

Note: here's what the HDMI association has to say on it:

Q. If an HDMI accessory device (i.e. switch box, cable booster) does not have a dedicated power supply, is it still compliant and will it work?

An HDMI device that has active electronics should have a provision for external power in order to be compliant (e.g. a receptacle to allow the use of a standard power adapter, sometimes called a power “brick”). Here we are drawing a distinction between “active” devices that actually have some powered electronics, and “passive” devices, such as some switches (more on those later).

Some active devices, such as actively powered HDMI cables or in-line signal extender boxes, will by default attempt to power their electronics by taking power from the 5V line (+5V power) available on the HDMI connector. The HDMI specification requires all source devices to provide at least 55mA (milliamps) on the 5V line for the purpose of reading the EDID of a display. While 55mA is not enough current to operate most HDMI accessory devices (which typically require about 100 to 150mA), most source devices on the market today provide significantly more current on the 5V line than the HDMI specification requires. As a result, the vast majority of accessory devices can operate when interfaced with a source device that provides more than the required current (i.e. over 100-150mA) on the 5V line. However, manufacturers should provide a provision for their powered HDMI accessory devices to obtain external power, and consumers are encouraged to look for this external power provision when purchasing such products.

Looking to the future, not all HDMI devices may provide this much power over the 5V line. For example, as HDMI expands into more and more portable applications (cameras, camcorders, laptops, etc.), power consumption is often much more of an issue, and such devices may not power the 5V line with the > 100mA required by such “active” devices. Again, consumers should consider ensuring that their active HDMI accessory device purchases have a provision for external power for this reason.

Total speculation: it's reasonably likely that the Raspberry Pi wires the 5V HDMI directly to the Pi's 5V input. If so, the VGA converter will have power equal to 1A minus whatever the Pi uses.

0

I am using EXACTLY that HDMI to VGA converter on my RPi model B's as well as on my RPi 2's, and have no issues. The only two watchouts with the use of a converter like this are:

  1. On higher resolutions you might have to make overscan adjustments, otherwise you get a black box around the screen (i.e. The display from the RPi does not fill the entire screen).
  2. When either your screen goes into sleep mode, or you switch screens if you have a KVM switch, you might need to replug the converter to get the RPi to display again.

Neither has been a significant inconvenience for me.

  • I asked the seller yesterday and he said "Sorry, it doesn't work with your device"...? – user20151388 Oct 14 '15 at 9:10

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.