Raspberry Pi + HDMI to VGA


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by Daantjuh001 » Sun Nov 04, 2012 9:58 am
Goodmorning,

A week ago I received my Raspberry Pi. I saw it needed at least 700mA so I used my Android charger which gives 700mA. It's currently using an HDMI monitor, but I want to use my VGA monitor since the HDMI monitor is not mine, and the VGA is.

I saw the Raspberry Pi peripherals page on the wiki, and I saw this one: http://dx.com/p/hdmi-v1-4-male-to-vga-f ... 5cm-130458. Now I wanna buy it, however, I think the converter is using some power too, so I don't know if the Raspberry Pi will have enough to run himself. Does anyone of you have experience with this converter, and if yes, do you think/know for sure, that they both run perfectly on the Android charger which gives 700mA?

With kind regards,
Daantjuh001
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by mahjongg » Sun Nov 04, 2012 12:15 pm
I think you answered your own question.
Such an adapter uses say 300mA, so when you only provide 700mA, and you subtract 300mA, you are left with only 400 mA, while the minimum is 700mA.
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by Daantjuh001 » Sun Nov 04, 2012 12:22 pm
Oh, great :L Do you have a suggestion for a charger, with which I can run my Pi, the HDMI to VGA converter, and maybe a WiFi adapter with it?
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by mahjongg » Sun Nov 04, 2012 1:54 pm
Forget about that, there is a fuse on board which might trip at 1.1A!

Any well designed 5V 1A power supply with an USB output port, and/or with an mini USB output cable should be fine to power the PI, and have some reserve. The wiki list suitable and unsuitable devices. But for powering the WiFi adapter you most often (some people claim they used an wifi adapter directly on the PI) would need a powered hub, and regarding the VGA adapter, you have another problem, as there is also a diode in-between the PI and the HDMI output to prevent the HDMI device from attempting to power the PI, and that diode is rated just 200mA. Using an 1A PSU, and no wifi adapter you might be able to power the VGA adapter, or you might not, depending on exactly how much power it draws, if you are unlucky it won't work, if you are even more unlucky it will also blow up the fuse, which takes days to recover somewhat and/or will blow out the diode.

There are reasons why using an self powered VGA adapter is strongly advised, and why the FAQ says that anything beyond a mouse and keyboard needs a powered hub, for power as much as for expanding the number of ports.
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by Daantjuh001 » Tue Nov 06, 2012 8:46 am
Hmm, so if I buy this one: http://uk.rs-online.com/web/p/products/7263053/?, + the HDMI to VGA converter it should run fine?
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by RaTTuS » Tue Nov 06, 2012 8:58 am
http://www.catb.org/esr/faqs/smart-questions.html <- ask smart Questions
"That's not right, the badgers have moved the goalposts."
1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX - Prosliver FTW
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by Daantjuh001 » Tue Nov 06, 2012 11:18 am
I wanted that one, but they don't deliver in the Netherlands, and or I don't have a credit card.
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by RaTTuS » Tue Nov 06, 2012 11:31 am
http://www.catb.org/esr/faqs/smart-questions.html <- ask smart Questions
"That's not right, the badgers have moved the goalposts."
1QC43qbL5FySu2Pi51vGqKqxy3UiJgukSX - Prosliver FTW
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by gelfling6 » Sat Dec 08, 2012 7:39 pm
I've got the same problem, but it doesn't seem to be stealing too much from the Pi.. I'm powering the Pi through a Dynex 7-port USB hub both via a Type-A to Mini-power connector to the Pi's power, but also through a type-A to Mini-B 5 pin plugged into a USB socket on the Pi, and into the hub's main input.) Power to the hub is from a 5V 3.0A supply, (which, I';m hoping is providing at least 2A to the Pi).. I got a similar adapter for my Pi, to try and view on an HP L1908W LCD screen.. But.... getting nothing from the display, but noticing the Pi is booting-up via it's activity LED.
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by advanced » Fri Jan 04, 2013 6:45 pm
what about these "cables" ? http://www.youtube.com/watch?v=ML15qIyCUAU
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by mahjongg » Fri Jan 04, 2013 7:00 pm
Those are not cables, its impossible with just a cable. The cables do exist, but only for situations where a video card misuses the HDMI connector to send out analog VGA signals, which is against HDMI specifications!

What does work (sort of) are converter boxes, but as said before these all use more than 200mA from the HDMI connector, and in theory the PI can only deliver less than 200mA to the HDMI connector. Regardless some people try and get lucky. Not recommended!
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by DexterLB » Tue Jan 15, 2013 6:24 pm
I was able to successfully hack one of those cheapo chinese converter boxes to use external power.

A big problem was that the whole thing was filled with silicone sealent, and I had to remove it, cut off the cable, remove all that's left of the wires and the silicone, and re-solder all the wires except the +5v line.

I then soldered a couple of wires for external power, and, though I was sceptical myself, the thing worked!

Here is a pinout table I made to solder the wires in the right order.

Here are some pictures of the converter in action
Last edited by DexterLB on Wed Mar 27, 2013 8:26 am, edited 1 time in total.
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by voxit » Tue Mar 26, 2013 7:50 pm
Dexterlb this doesn't work anymore

Here is a pinout table I made to solder the wires in the right order.

can you repost it
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by DexterLB » Wed Mar 27, 2013 8:28 am
hmm, it appears that my subdomain had expired. I moved it to a new one and fixed the link in the original post.
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by voxit » Wed Mar 27, 2013 10:56 am
Many thanks, there was to much silicone on my adapter, when i tried to remove it i broke some wires.
But now it works :D.
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by DexterLB » Wed Mar 27, 2013 11:58 am
I'm glad my setup worked :)
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