Raspberry Pi Forums

Posted: **Mon Jan 19, 2015 5:07 am**

Hi!
I'm going to buy my first Raspberry Pi (B+). I'm going to connect it to a projector that only has a VGA port. I can either get Gert's VGA 666 addon or an HDMI to VGA (cable) converter.
While I'm sure the addon should be better than the standard cable converter, I could not find a concise list of pros and cons anywhere.
So, does anyone know of such a list, or better yet, can say what the advantages/disadvantages are for each of these solutions?
Thanks in advance!!!

***Edit, if you want to know what the answer is, here's a summarized table of what the friendly RPI people say (I put it in a code environment for mono space characters):

Code: Select all

|What             |Gert's VGA 666                            |HDMI to VGA converter|
------------------------------------------------------------------------------------
|price            |cheaper                                   |                     |
|external power   |none                                      |may be necessary     |
|GPIO             |occupies most including i2c and SPI bus   |leaves it free       |
|color depth      |666 (262,144)                             |888 (16,777,216)     |
|difficulty       |soldering and editing system files        |plug and play        |
|guarantee to work|yes                                       |no                   |
|case             |only "layer cake" style (e.g. Pibow coupe)|all version specific |
|multiple screens |yes                                       |no                   |

Posted: **Mon Jan 19, 2015 6:41 am**

i know only three points to note...

pro:
# the VGA 666 is cheap and simple.
you can, if you can, build it yourself. the VGA 666 do not need extra power.

contra:
# the VGA 666 is using the full GPIO connector.
so you wount be able to use your GPIOs anymore for other purpose than VGA 666.

# a higher colour depth than 666 is not possible with VGA 666.
you stuck at 262144 colors max, 888 truecolor (16777216 max) is not possible.

maybe other people will know and tell you more pros and contras...

Posted: **Mon Jan 19, 2015 6:50 am**

active HDMI - VGA converter
Pro:
Easy setup (just plug and play).

Con:
Not guaranteed to work.
More expensive.

gert VGA board
Pro:
Works everytime.

Con:
Requires assembly.
Requires modifying the pi operating system files to output to the VGA.
Takes up many of the GPIOs. (Not all of them, there are some left over).

Posted: **Mon Jan 19, 2015 11:10 am**

Thanks for the reply guys! I didn't quite understand, does the 666 offer better color/resolution/fps/"quality" than the cable converter?

Posted: **Mon Jan 19, 2015 11:53 am**

12.yakir wrote:Thanks for the reply guys! I didn't quite understand, does the 666 offer better color/resolution/fps/"quality" than the cable converter?

lower color resolution (6 Bit/Pixel instead of 8)
no difference in screen resolution, fps

Posted: **Mon Jan 19, 2015 12:33 pm**

A HDMI converter still allows you to use a case.

Posted: **Mon Jan 19, 2015 1:30 pm**

mancity wrote:A HDMI converter still allows you to use a case.

Using Gert's VGA 666 adapter doesn't prevent the use of all cases - some of the "layer cake" style cases can be used with minimal modification (eg. the Pibow coupe).
Trev.

Posted: **Mon Jan 19, 2015 4:30 pm**

12.yakir wrote:Thanks for the reply guys! I didn't quite understand, does the 666 offer better color/resolution/fps/"quality" than the cable converter?

666 is not the number of evil - it is the number of bits per color channel.
666 = 6bit red, 6bit green, 6bit blue = > 64levels red * 64levels green * 64levels blue => 262144 colors max in total.
compared to truecolor - 888 or also known as 24bit color depth (total)...
888 = 8bit red, 8bit green, 8bit blue = > 256levels red * 256levels green * 256levels blue => 16777216 colors max in total.
for multimedia i think it is better to have the full range of colordepth with 24bit/888/truecolor - otherwise you may notice some color issues - depending on your monitor/projector/beamer or your expectations and entitlements in quality is.

resolution in meaning of count of pixels and image refresh frame rate will be not affected by the number of colors.
only the depth of color is different.

Posted: **Tue Jan 20, 2015 12:42 am**

Thanks! I've summarized your answers in the first post (in case someone wants to quickly know what the answer is). Feel free to add/correct and I'll update it.

I have to admit, I started this off believing that Gert's VGA 666 addon would be the better choice out of the two, but reviewing the answers (see the table) tips it over to the cable converter... Set aside the 10 extra $, and the need to verify with previous users that a specific cable converter model works and works without any external power, it seems like I'd get better colors, no soldering, plug&play, and more case choices if I choose the cable converter.

I don't know why, but I feel disappointed...

Posted: **Tue Jan 20, 2015 12:50 am**

The one thing that the Gert board gets you is the ability to run two monitors (one HDMI and one VGA) on the Pi.

That's the only reason I'd consider using VGA with the Pi.

Posted: **Tue Jan 20, 2015 12:59 am**

Important point (updated the table), but still, in my personal usage case (home theater), I think I'll go for the cable converter.

Posted: **Tue Jan 20, 2015 8:27 am**

the VGA board should be modified from

GPIO |occupies some

to

GPIO |occupies most including i2c and SPI bus

Posted: **Thu Jan 22, 2015 11:24 pm**

Sorry for the slow reply, done.

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