lightmaster
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Location: Georgia, USA

Power RPi Zero with modified HDMI

Thu Jul 21, 2016 4:15 am

I know you can't use the 5v line in an HDMI cable to power a RPi, however I noticed on the pinout for an HDMI connector that there's an unused pin 14. Would it be possible to open up a HDMI cable and hijack the 14 wire, disconnecting it from both HDMI connectors and wire the TV side into the 5v wore from a USB charger and the RPi side onto the 5v pin of the GPIO? I'm fairly new to RPi, and the entire electronic DIY area, so I might be way off base with this idea. Just wanted the opinion of someone more experienced than myself before I destroy a perfectly good HDMI cable and possible short out a new RPi.

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MarkHaysHarris777
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Re: Power RPi Zero with modified HDMI

Thu Jul 21, 2016 4:55 am

This might work; and probably will work intermittently at least.

... the problem will be the length of the wire (not wanted voltage drop) and the gauge of the wire... it should be 18-22 AWG cable as short as possible. The hdmi cable wire is probably too fine, and its probably too long... but, who knows...

There are 1m (3 foot) hdmi cables... you might try one of those... another thing to keep in mind is that not all hdmi cables provide all wires... if the wire isn't used many hdmi cable producers will leave the wire out !

marcus
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lightmaster
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Location: Georgia, USA

Re: Power RPi Zero with modified HDMI

Thu Jul 21, 2016 5:24 am

So you can power it through the 5v GPIO pin? And assuming my HDMI cable does have the 14th unused wire, the only harm in trying would be that it my be underpowered and crash, but ultimately be undamaged, right?

I'm hoping to try to integrate my RPi Zero into a controller and run RetroPie on it, and I'd like if the only wire coming out was just the HDMI wire. A separate power wire wouldn't be ideal, but could still deal with it.

blaablaaguy
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Re: Power RPi Zero with modified HDMI

Sat Jul 23, 2016 1:12 pm

Wont that kinda acheive the same thing as taping a micro usb cable to the hdmi cable?
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jonathancorrin
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Re: Power RPi Zero with modified HDMI

Sun Mar 12, 2017 4:05 pm

Did you ever get this to work?

lightmaster
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Location: Georgia, USA

Re: Power RPi Zero with modified HDMI

Sun Mar 12, 2017 10:41 pm

jonathancorrin wrote:Did you ever get this to work?
My HDMI cable didn't have the 14th wire in it at all.

jonathancorrin
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Re: Power RPi Zero with modified HDMI

Mon Mar 13, 2017 11:19 am

Did you try using pin 18?

According to the HDMI reference material (see link below) the standards are 55mA but most manufacturers are transmitting 100 - 150mA and according to PiTV (second link) the Pi Zero and Pi Zero W are in this territory.

http://www.hdmi.org/learningcenter/kb.aspx?c=13#42

http://raspi.tv/2017/how-much-power-does-pi-zero-w-use

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