On Wed, 06 Jan 2021 18:50:04 +0000, druck wrote:

> On 06/01/2021 17:04, Martin Gregorie wrote:
>> On Wed, 06 Jan 2021 16:41:25 +0000, Theo wrote:
>>
>>
>>> Maybe there are use cases where people want to power their Pis from
>>> HDMI, I don't know.
>>>
>> Doing that would make the installation tidier if I wanted to glue the
>> Pi enclosure to the back of the screen - provided that the screen can
>> provide the wattage needed. Is that likely, bearing in mind that, if I
>> did that, I'd also want it to power a keyboard and mouse via the USB
>> sockets on the Pi.
>
> HDMI will never power a Pi, way too thirsty.
>
> Similar devices such as an Amazon Firestick have to have an external
> PSU, as they require more power than even the TV's USB port can supply.
> Note that if this does seem to work, you are probably overstressing your
> TVs electronics, which will lead to premature failure.
>
Makes sense in light of the content of earlier posts: if the HDMI cable
only carries power so it can wake up some HDMI chip in the, possibly
powered-off, device at the far end which tells the initiator what it is
talking to and what that can or cannot do, then it follows that doing
this only needs a few milliamps.

I thought that might be the case: thanks for confirming it.


--
--
Martin    | martin at
Gregorie  | gregorie dot org

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