HDMI to VGA Conversion


12 posts
by Mortimer » Thu Jun 14, 2012 9:47 pm
I thought I would let people know how I am displaying the output of my RPi, as it might help some others out too.

I am using one of these:
Image
Bought from Amazon market : http://www.amazon.co.uk/exec/obidos/ASI ... os_product

At the moment it is sitting between the RPi and an old Philips 170B 1280x1024 LCD monitor, and after a little messing around (viewtopic.php?f=26&t=8406) It is working perfectly at the native resolution of the monitor.

The config.txt is as follows:
Code: Select all
hdmi_drive=2
hdmi_group=2
hdmi_mode=36
disable_overscan=1


At the moment I am not getting any sound through the to the analogue output of the converter. At the moment this seems to be because sound is disabled by default anyway.

Ultimately this converter is intended to be used with my Sagem HD-D45 DLP rear projection TV. This doesn't have any HDMI inputs, only a single DVI-D input, used by my FreeView receiver. A single component video input and a single VGA input. I am hoping that this converter will work just as well with the component input, thus giving me two HDMI inputs to use. That is an experiment for another day.
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by JeremyF » Fri Jun 15, 2012 1:27 am
{sig} Setup: Original version Raspberry Pi (B, rev1, 256MB), Dell 2001FP monitor (1600x1200), 8GB Class 4 SD Card with Raspbian and XBMC, DD-WRT wireless bridge
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by Mortimer » Fri Jun 15, 2012 8:10 am
I tried adding to the Wiki, but my submission disappeared after being submitted. I'll wait and see if it reappears, it might be awaiting vetting before appearing properly, before trying again.

I have a new link to Amazon, as the seller I bought from is out of stock, but I found another:
http://www.amazon.co.uk/Inputs-Componen ... 00797ZZ4S/
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by Mortimer » Fri Jun 15, 2012 8:40 pm
Managed to post the information to the Wiki at last!
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by Mortimer » Tue Jun 19, 2012 8:01 pm
Very odd:

When I boot the RPi from the 2GB Kingston SD-Card the image fits perfectly on the screen.

When I installed the same OS onto the InoV8 16GB card and booted it with the exactly the same config.txt file, the image is raised about 2cm, and there is not enough adjustment in the monitor to bring it all the way back down. Replacing the "overscan_disable=1" entry with the four overscan adjustments set to -48, the image is perfect again!

I also discovered that playing with the CPU_freq setting can also affect the vertical alignment of the image on the display. I don't know if this is because of the way the converter works, but in any event I wouldn't expect the choice of SD-card or CPU clock frequency to affect the HDMI output of the RPi.

Is this a known phenomenon? Is there an explanation for this?
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by marcoalexcampos » Fri Jun 22, 2012 3:02 pm
£39.49 is quite expensive compared to the RaspberryPi board... isn't there a more economic solution?

I have 20-30 old VGA monitors on the shelf and I'd like to use some of them with RaspberryPi on a school, but for that price I can buy a ARM card already with a VGA port and a bit more RAM (Though I'm not interested in that solution).

Any other ways to connect the RaspberryPi to a VGA CRT monitor?

Thank you for any input on this.

Cheers,
Marco Campos.
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by JeremyF » Fri Jun 22, 2012 4:11 pm
{sig} Setup: Original version Raspberry Pi (B, rev1, 256MB), Dell 2001FP monitor (1600x1200), 8GB Class 4 SD Card with Raspbian and XBMC, DD-WRT wireless bridge
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by arm2 » Fri Jun 22, 2012 7:44 pm
Mortimer wrote:Managed to post the information to the Wiki at last!

I've tested a few HDMI to VGA adaptors and many will work but only at lower resolutions. None of the adaptors that didn't have their own Power Source would work at higher resolutions some only managed 800x600 or 1024x768. Can I suggest you qualify your wiki posting with (Only tested to 1280x1024) that couls save a few peole wasting their money!

Does it come with a power adaptor? And were you using it?
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by marcoalexcampos » Mon Jun 25, 2012 10:52 am
Thank you. I'll order one to test for now and let you know how it worked

I hope in due time that these adapters drop to something like 5$, and maybe Farnell and RS would make a bundle of RaspberryPis, power, box and VGA adaptor. :)

Best regards,
Marco.
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by mahjongg » Mon Jun 25, 2012 10:57 am
Not much chance of that, the "normal price" for a device like that is something like $300!
Its just because of economies of scale and cheaper simpler designs that the price has come down to this level.

You must understand that such a device contains a complete screen grabber, video RAM to contain a complete screen, VGA video logic to create a VGA signal, and a microcontroller to manage everything. Only with a single chip solution (except RAM) it was possible to bring back the prince to below $50 in the first place.
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by Mortimer » Mon Jun 25, 2012 11:13 am
arm2 wrote:
Mortimer wrote:... Can I suggest you qualify your wiki posting with (Only tested to 1280x1024) that couls save a few peole wasting their money!

It already does,
Wiki entry wrote:Tested against a Philips 170B 1280x1024 LCD monitor, producing a full native resolution image.


arm2 wrote:Does it come with a power adaptor? And were you using it?

Yes it does, and yes I was, because it won't work at all without it.
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by jphphotography » Wed Jul 11, 2012 4:25 am
For others that are looking for a cheap HDMI to VGA converter I took a gamble on this one from ebay for $6.60 +$5.99 shipping and it seems to work great.
http://www.ebay.com/itm/ws/eBayISAPI.dl ... OC:CA:3160

I haven't tried a bunch of modes yet but this was my config file for using it at 1024x768

arm_freq=800
disable_overscan=1
hdmi_drive=2
config_hdmi_boost=0
hdmi_group=2
hdmi_mode=16
hdmi_force_hotplug=1

Initially I used config_hdmi_boost=4 but later tried it at 0 and it still worked so I just left it there.
If you want to play around with the values go to http://elinux.org/RPi_config.txt for all of the possible settings.

For $12.59 shipped that's a pretty good deal if you ask me. Its great because I have an abundance of VGA monitors and no HDMI displays other than my TV.

Cheers

PS Once I have time to test it at higher resolutions I'll post back with my findings.
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