Raspberry pi 2 b & video glasses(ID: 1452) composite video

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
adagirlfruit
 
Posts: 10
Joined: Fri Jul 10, 2015 11:43 am

Raspberry pi 2 b & video glasses(ID: 1452) composite video

Post by adagirlfruit »

I am having an issue getting https://www.adafruit.com/product/1452 to work with the composite video of the Raspberry pi 2 b.

To summarize before I get into detail I will list what I have done to try to resolve this issue first and my conclusion(s)/
It would be very helpful if a tech could plug a set of glasses into a rasp pi 2's composite video and see if they can help.

Here is my setup:
here is a pic of my setup:
here is a pic of my setup:
800x600set.jpg (147.7 KiB) Viewed 684 times
To clarify I have plugged this cable both into the rasp pi 2's composite video jack, and the smaller end into the glasses pack:
800x600 cable.jpg
800x600 cable.jpg (154.79 KiB) Viewed 684 times
No matter the composite settings in /boot/config.txt (tried ntsc, ntsc japan,pal, and brazillian pal),
also other tweaks such as hdmi_ignore_hotplug etc.. etc..(full config.txt posted at the end)

I will usually get just a blank screen on the glasses, but sometimes I will get a nanosecond flash of the pi 2's screen every few seconds. It varies on attempts from nothing to frequent flickers. It is often also distorted if/when you get get a glimpse of it flickering as so:
800x600nanosecond.jpg
800x600nanosecond.jpg (125.57 KiB) Viewed 684 times
I have gone over the config.txt file pretty thoroughly
I have tried removing the case to make sure there is a good connection between the board and the glasses plug
I have tried it on a different composite video player, initially it worked but was VERY flickery but on retest it seems better -ish..
I have tried switching the cables around but its pretty obvious yellow is video
I have rechecked all connections (its easy to miss an unseated connection on the glasses as they snap in)
I have concluded that either the glasses are wonky, the composite video plug on the pi 2 is defective, or
the male/male mini cable included with the video glasses is of the wrong type. The cable does look to be TRRS but perhaps the video signal is not in position 4 on the sleeve. I noticed I can get faint audio out of the wrong earpiece connection so this might explain why I am getting intermittent video.
No on seems to sell composite cables in the brick and mortar stores anymore, I even resorted to going with an powered hdmi adapter and a new config but that thing don't seem to work on anything (after testing) much less the raspberry pi2.

I would splice the mini cable and mess with the wire order in it, to see if I can get the signal order right on the sleeves (if this would be a good way to resolve sleeve order) but if the glasses are the culprit I would likely lose any chance of an rma.
Any help would be appreciated! :)

config.txt

Code: Select all

#For more options and information see 

#http://www.raspberrypi.org/documentation/configuration/config-txt.md

#Some settings may impact device functionality. See link above for details


#uncomment if you get no picture on HDMI for a default "safe" mode

#hdmi_safe=1


#uncomment this if your display has a black border of unused pixels visible

#and your display can output without overscan

#disable_overscan=1


#uncomment the following to adjust overscan. Use positive numbers if console

#goes off screen, and negative if there is too much border

#overscan_left=16

#overscan_right=16

#overscan_top=16

#overscan_bottom=16


#uncomment to force a console size. By default it will be display's size minus
# overscan.

#framebuffer_width=1280
#framebuffer_height=720


#uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1


#uncomment to force a specific HDMI mode (this will force VGA)

#hdmi_group=1
#hdmi_mode=1

# uncomment to force a HDMI mode rather than DVI. This can make audio work in

#DMT (computer monitor) modes

#hdmi_drive=2


#uncomment to increase signal to HDMI, if you have interference, blanking, or

#no display

#config_hdmi_boost=4




#uncomment for coposite NTSC 0 (usa), 1 ntsc japan, 2 pal, 3 pal brazillian

sdtv_mode=0


#aspect ratio, did not see an entry but putting 4:3 here are choices

#this is a comment sdtv_aspect 1 = 4:3, 2 = 14:9, 3 = 16:9 

sdtv_aspect=1

#sdtv_aspect=2

#sdtv_aspect=3

#ingnore hdmi all together, uncomment later maybe see if it works but this forces compsite mode which we want

hdmi_ignore_hotplug



#uncomment to overclock the arm. 700 MHz is the default.

#arm_freq=800


#Uncomment some or all of these to enable the optional hardware interfaces

#dtparam=i2c_arm=on

#dtparam=i2s=on

#dtparam=spi=on


#Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README



#increasing framebuffer depth to 24 to match glasses bit color

framebuffer_depth=24



#gunna increase the frame buffer width to 320 to match the glasses as well see if that helps
framebuffer_width=320



#gunna increase teh frame buffer height to 240 to see if that helps also
framebuffer_height=240



#NOOBS Auto-generated Settings:

#hdmi_force_hotplug=1

#config_hdmi_boost=4

#overscan_left=24

#overscan_right=24

#overscan_top=16

#overscan_bottom=16

#disable_overscan=0

User avatar
adafruit_support_mike
 
Posts: 67454
Joined: Thu Feb 11, 2010 2:51 pm

Re: Raspberry pi 2 b & video glasses(ID: 1452) composite vid

Post by adafruit_support_mike »

This page has the TRRS connections for the RasPi's composite output jack:
http://www.raspberrypi-spy.co.uk/2014/0 ... ideo-jack/

Check to make sure the cable has the signals in the correct order.

User avatar
adagirlfruit
 
Posts: 10
Joined: Fri Jul 10, 2015 11:43 am

Re: Raspberry pi 2 b & video glasses(ID: 1452) composite vid

Post by adagirlfruit »

As stated in the post I am aware of the possible conflict with the TRRS cable.
The reply post only points to what I was l was already mentioning. I went ahead and checked the user comments on that page anyway, however there were no relevant posts on these glasses there.
There is no real answer. I suppose if I had a meter I could test the plugs but the do go through a battery box on the unit.
The only true way to test is in the 3 way adapter that comes with it but is irrelevant as it is not 3.5mm.
I could test the small male/male cable I am using but that won't tell me a whole lot, only that continuity is leading from one sleeve to the next (3.5mm to small proprietary? cable.
After this point it again goes through the battery box which I am not sure if that switches the signals, then again to the small usb that plugs into the glasses themself (it could then again switch signal there)

So other than trying to track down an alternative cable or splicing and dicing the male/male adapter plug, I am back at square one.

In short I just thought there might be some answers here about the product and was hoping someone at adafruit would look into and document the issue for the product. I am not against slicing and dicing but I am unsure if the product its self is defective or its the wrong TTRS. It would just be helpful if this was tested and documented, and if the included two way male/male cable could be spliced and reordered (but kept stock), the end user could splice it on their own for connection to the pi 2 or other composite device requiring a CTIA/APPLE plug.

It would be really nice if a tech at Adafruit did the documentation of the product is all and tried chopping a cable and posting a demo and understood what the product is likely to be used for now that it is becoming harder and harder to find composite pi devices with the new pi2 being out.

All else fails I'll document and post test it on my own but the information will be buried in the forums and unofficial information at that (i'm no certified tech).

Thanks in advance :)

User avatar
adagirlfruit
 
Posts: 10
Joined: Fri Jul 10, 2015 11:43 am

Re: Raspberry pi 2 b & video glasses(ID: 1452) composite vid

Post by adagirlfruit »

Just to clarify, this set up would be pretty cut and dry if this were on an older pi with a composite rca jack, as seen in the wearble pi demo.

I DO get composite video through the yellow connector on the other included 3 way split cable when hooking to a different composite source. So the pinout must be right (at least on this cable)

However the pi2 has a 3.5mm jack instead of rca, so you must use the other cable that is included (the male mini/male 3.5mm)
I have gone ahead and tested this image on a second raspberri pi2 to verifiy it was not the pi2's 3.5mm jack malfunction. It looks like for some reason or another they must have reordered the included male/male adapter cable from one end to the other in this cable.

I would like to know how to rewire this cable if that is the case. Even if I say to the wind with it, and cut this cable and manage to find the one that gives video and connect that and problem solved...audio via 3.5mm jack is a whole other ball of yarn (both hardware and software wise) and i'd likely cap off the other 3 wires (and then where is my ground wire!?)

Some would say "dude just buy a different cable and try it out", but the female connection on the battery box on the glasses is not a standard 3.5mm jack but some itty bitty proprietary-ish looking thing.

*edit
I'd still like to know how to rewire this existing male/male cable, but after watching Noe Ruiz and his wearable google glass clone video I did realize that I could just use the other 3 way split cable and try and find a third party all male 3 way rca to 3.5mm adapter cable of the right type and do it that way. (if that is indeed the issue). Still an open challenge to anyone who wants to tackle rewiring the existing male/male cable at Adafruit. I don't see an adapter in the Adafruit store either, which seems to be needed for the pi2 now and also possibly a few of the tft displays that are sold.

User avatar
adafruit_support_mike
 
Posts: 67454
Joined: Thu Feb 11, 2010 2:51 pm

Re: Raspberry pi 2 b & video glasses(ID: 1452) composite vid

Post by adafruit_support_mike »

A shown on the page linked above, the RasPi composite jack's video output is on the sleeve, and GND is on the ring closest to it. The tip and outermost ring are the left and right audio channels respectively.

If you need to establish the TRRS order of the pod that accepts video input for the glasses, use a multimeter to check continuity through the yellow RCA jack of the adapter that came with the glasses. The outer connector will be GND and the inner connector will be video.

Once you know the TRRS mappings for the signals, you'll know whether your cable is correctly wired as is, or whether you'll need to cut and splice.

User avatar
adagirlfruit
 
Posts: 10
Joined: Fri Jul 10, 2015 11:43 am

Re: Raspberry pi 2 b & video glasses(ID: 1452) composite vid

Post by adagirlfruit »

Well well well.. here is the lowdown of the dirty little secret of these glasses..
After running into no real help I tracked down a few issues with these glasses.

Firstly if you want right side audio on these glasses, your going to have to modify (possibly sand down) the mini usb connection housing and the small (2.5mm?) housing due to the fact that the manufacturer has put these connections too close together and both plugs with not fit at the same time, a major product defect not mentioned in the description.

As for the included male/male 3.5mm to 2.5mm? plug.. well after cutting this cable apart and pinning it out to a breadboard, it would seem that this is not a video plug at all. It seems to follow the OMTP/Nokia pinout AKA: it seems to be wired for mp3 and not video.

The pinout fresh out of the box (assuming they did not mess up standard audio pinouts as well) is:
T=LEFT, R1=RIGHT, R2=Microphone*, Sleeve=Ground.
* Despite what http://www.raspberrypi-spy.co.uk/2014/0 ... ideo-jack/ says about this layout in the diagram ( the last example provided for "mp3 players") there is no evidence that this connection is actually compatible with ANY video source that I am aware of and in my opinion should be labeled *microphone as per the OMTP/Nokia spec. In the very chart shown, as well as any other chart showing any known video connection, including camcorder/av, CTIA/APPLE, Raspberry Pi B+, and Raspberry Pi 2 B, this cable can not connect to ANY sort of video source.


This cable might be able to use mp3 over your video glasses without the use of video. However, even this is suspect because your ground plane will be wrong (your ground is going to video over a raspberry pi B+ and raspberry pi 2 B.

These are enamel coated wires, intermixed with strengthening filament (possibly kevlar). Typical mini headphone jack wire that is a REAL pain to deal with. These wires will not take solder without burning them and sanding them down. If you don't want to solder them (ie: twist them together), you must also do this method as the enamel is non conductive. A copious amount of flux also goes a long way here it would seem if your going to solder.

Here is the rewired job layout, I went ahead and skipped connecting the left and right speakers myself as I don't have alsa configured and it gives an annoying hum on the audio.
cable redorder.png
cable redorder.png (28.1 KiB) Viewed 590 times
Note that even though connecting ring 2 of the mini connector to the sleeve of the pi b+/2b should connect video, it won't work unless the sleeve of the mini is connected to ring2, ring 1, or the tip. I suspect this to be grounding at any of these points and you will get video, but I have chosen to place it to where the true ground should be which is ring 2 as shown in the diagram.

Happy Headaches!

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”