KSShooter
Posts: 23
Joined: Wed Jul 17, 2013 9:38 pm

Connecting Motorola Lapdock to Pi with connectors

Thu Sep 05, 2013 7:27 pm

Have a Motorola Lapdock for Atrix, and trying to connect my Model B RasPi.

Connctors from China finally came in, and to no surprise - no joy getting the Lapdock turned on. So, couple questions:

First - do both the micro USB and the HDMI need to be connected at the same time to energize the Lapdock? (i.e. is the Lapdock watching for current drain through the micro USB and the DDC/CEC ground have to be made at the same time?)

Second - Every reference I can see to deal with the DDC/CEC ground issue ALWAYS involves hacking the Lapdock to either put a Type A HDMI connector in it, or to short DDC/CEC with switch, etc. Is it not possible to hack the connector or cable to do the same? Seems far easier and much safer to hack a $2 connector/cable rather than hack the Lapdock.

I have an HDMI connector like the following: http://www.miniinthebox.com/hdmi-female ... om=sysmail

I'd really prefer female cables to attach to lap dock, then go out to appropriate connectors for HDMI and USB - but I can't seem to find any. Any luck here for anyone?

tvoverbeek
Posts: 97
Joined: Mon Feb 04, 2013 9:50 am
Location: Fieberbrunn, Austria

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Sep 05, 2013 7:48 pm

I also have the Atrix Lapdock and a model B RasPi and the combination works fine.
The HDMI connection is needed otherwise the Lapdock does not turn on.

The USB connection is not needed. You can use the Lapdock as display only.
Of course in this case you need then to power the Pi externally and connect a USB keyboard (not the lapdock one) or use the network to connect via e.g. ssh.

The other way around, only connecting the usb without the display does not work, since the lapdock does not turn on.

With both the HDMI and USB connected to the lapdock the Pi should turn on, since it gets power via the USB (backfeeding). For the very first Pis this does not work due to the PolyFuse.

I have used these small extension cables http://www.amazon.com/Cable-Adapter-Set ... B007RFRHIY and use a micro female to female HDMI adapter like yours on the end of the HDMI extension cable and then a normal HDMI cable.

Hope you get yours going.

Ton van Overbeek

KSShooter
Posts: 23
Joined: Wed Jul 17, 2013 9:38 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Sep 05, 2013 7:56 pm

I've seen exactly what you noted on Amazon. However, it is described as an "Micro-HDMI (M) to Micro-HDMI (M) Cable". You need a F->M or F->F HDMI.

The picture isn't all that distinct, and it may be that one end of the HDMI is actually a female socket sticking out of the plastic, but I'm not sure. Reviews seem to indicate it works - but I've seen too many Amazon reviews where some idiot puts their review of item A on item B. Or says how bad model A1 is, and they put the review on Model Q5. That kind of stuff.

Is this actually the correct cable?


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AndrewS
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Location: Cambridge, UK
Contact: Website

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Sep 05, 2013 10:26 pm

I use one of these to connect my Pi to my lapdock, works fine http://www.amazon.co.uk/LINDY-Micro-HDM ... 007D1T9RO/

Have you read through this thread yet? http://www.raspberrypi.org/phpBB3/viewt ... =63&t=6747

KSShooter
Posts: 23
Joined: Wed Jul 17, 2013 9:38 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Sep 05, 2013 10:31 pm

AndrewS wrote:I use one of these to connect my Pi to my lapdock, works fine http://www.amazon.co.uk/LINDY-Micro-HDM ... 007D1T9RO/

Have you read through this thread yet? http://www.raspberrypi.org/phpBB3/viewt ... =63&t=6747
I've read almost all threads, etc. I can find.

Most items pointed to by links are no longer available. Yes, I know the eBay auction is over - they simply aren't available anymore. Or - they are from the UK, and by the time you buy it and ship it to the USA - price is prohibitive. That's why I'd rather "mangle the dongle" I've got.

I've gotten info from another source, and I think I can alter the dongle/connector I've got and make it work.

KSShooter
Posts: 23
Joined: Wed Jul 17, 2013 9:38 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Fri Sep 06, 2013 11:26 pm

Modified the dongle - after cutting away the shell. Simply shorted pin 17 of the HDMI connector to shell ground - works.

Pics:

Original:
Image

After "denuding":

Image

Modified:
Image

And end result:

Image

For now, I've left everything "bare". I kept a bit more wire in the short so I could add a switch, if I wanted. These circuit traces are very tiny, and I didn't want to have to go through the pain yet again of trying to solder a wire on those small traces. The Lapdock I got was one of those new-in-box (mine was completely sealed) English/Hebrew keyboard units. The Hebrew letters are small and in the lower right corner, and really aren't terribly noticeable. At least to me. I'm a touch typist anyway, so no big deal. Keyboard and mouse work. As you can see - Xwindows works too.d

Not sure how I'll finish it off. Could encase it in epoxy or JB weld - something like that. I may combine both the HDMI and micro USB together into one cohesive unit to give a bit more support to each other, and possibly shape the epoxy (or whatever) to the curve of the tray where the Atrix would normally sit. That way it would put less pressure on the connectors, etc.

So - it works, and I haven't "butchered" the Lapdock - my main goal at this point. I may well do that in the future, but for now I wanted something that worked without modifying everything. "Butchering" a $2 HDMI connector was no big deal, and I've still got a spare connector.

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LDighera
Posts: 44
Joined: Wed Aug 29, 2012 1:04 am
Location: Santa Barbara, California, USA

Re: Connecting Motorola Lapdock to Pi with connectors

Wed Sep 11, 2013 5:42 pm

KSShooter wrote:Modified the dongle - after cutting away the shell. Simply shorted pin 17 of the HDMI connector to shell ground - works.
I'm thinking this may be what prevents my LapDock from displaying video when connected to the Rasberry Pi.

When I plug the RPi HDMI cable into the HDMI female to mini HDMI female adapter (same as your, but unmodified), I get a message from the LapDock saying: No Signal on HDMI port, and then it goes blank again.

Will your modification overcome that issue?

Thanks.

Best regards,
Larry

UPDATE:
I found that removing the plastic shield over the lapdock connectors enabled the HDMI cable to fully seat and video is now operational.
Last edited by LDighera on Thu Oct 31, 2013 5:48 pm, edited 1 time in total.
There is no expedient to which a man will not resort
to avoid the real labor of thinking.
-- Sir Joshua Reynolds

freebirds
Posts: 51
Joined: Wed Oct 30, 2013 5:05 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Oct 31, 2013 3:43 pm

KSShooter asked: "Is this actually the correct cable?" The cable KSShooter is referring to is "Cable Adapter Set for Motorola Atrix 4G - Micro-HDMI (M) to Micro-HDMI (M) Cable and Micro-USB (F) to Micro-USB (M) Cable"

Several times, I reported fraudulent advertising by seller1on1 to Amazon. seller1on1 describes this micro HDMI male to micro HDMI male cable as connecting to a lapdock. It cannot connect to any of the four models of lapdocks. All four lapdocks have a male HDMI connector. seller1on1 shipped me a male to male HDMI cable. Apparently, seller1on1 had initially shipped a male to female cable which is why the initial comments reported that the cable connected to a lapdock. I asked seller1on1 to exchange the HDMI. seller1on1 refused. I shipped back the cables.

seller1on1 also advertising a micro female HDMI to micro male HDMI cable and a micro female USB to micro male USB cable. Their listing is: "Chromo Inc Cable Adapter Set for Motorola Droid Bionic Micro-HDMI (F) to Micro-HDMI (M) Cable and Micro-USB (F) to Micro-USB (M) Cable"

I asked Amazon to ask seller1on1 if they were really shipping a micro female HDMI to micro male HDMI cable. Amazon failed to. I ordered the cables. seller1on1 again shipped a male micro HDMI cable to a male micro HDMI cable. seller1on1's alibi was that they were out of the female to male HDMI cable.

They are not out of the right HDMI cable. seller1on1 is also advertising a micro female HDMI to micro male HDMI cable by itself without a micro USB cable for $20. I asked Amazon to investigate whether they were actually shipping this cable. I am waiting for Amazon's investigation.

tvoverbeek wrote: "and use a micro female to female HDMI adapter like yours on the end of the HDMI extension cable and then a normal HDMI cable." I don't know whether tvoverbeek was shipped a micro female HDMI to micro male HDMI cable or a micro male HDMI to micro male HDMI cable like I was.

I cannot figure out how to use the second micro male HDMI to micro male HDMI cable that was wrongly shipped to me. tvoverbeek, where did you find a micro female to female HDMI adapter? What do you mean by "then a normal HDMI cable?"

Could members please completely describe components so other members don't need to ask for clarity?

freebirds
Posts: 51
Joined: Wed Oct 30, 2013 5:05 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Thu Oct 31, 2013 3:56 pm

I wish there was an option to edit a reply. I apologize for asking where to buy a micro female HDMI to A female HDMI connector as KSShooter had provided a link to it at:
http://www.miniinthebox.com/hdmi-female ... om=sysmail

I do not see how this adapter would help? Attach the micro female HDMI end to the micro male HDMI cable? Then what to do with the other micro male HDMI end of the cable? What do you attach the A female HDMI to?

bbc0
Posts: 9
Joined: Fri May 02, 2014 7:05 am

Re: Connecting Motorola Lapdock to Pi with connectors

Mon Jun 09, 2014 2:03 am

I have a different Lapdock to most. Mine has a cable at the back which has the micro USB and HDMI male connectors at the end. It says MOTLPDK100 on a label underneath.
I have had considerable problems getting it to work properly and start reliably. I now have to have all cable disconnected prior to staring anything including power to the Lapdock. I plug in the USB connection then power to the RaspPI , then connect HDMI I then watch for activity on my RaspPI before opening the lid and pressing the button. Once the screen comes on and has something displayed, I can then plug in power to the Lapdock and use the beast. I have modified the config.txt file to force HDMI as I have seen recommended elsewhere but still cannot deviate in any way and expect the thing to work.
This makes a mockery of the"build a cheap laptop" articles all over the' net and I still have a few questions. The main thing that I can't understand is why I have to disconnect power to the Lapdock and start it up on the battery. It's fine if the battery is fully charged, but if the charge is low, forget it. I am hoping that there might be a work around for this but so far have found nothing. Anyone have any ideas?
BBC0

hukim0531
Posts: 1
Joined: Fri Aug 01, 2014 5:27 pm

Re: Connecting Motorola Lapdock to Pi with connectors

Fri Aug 01, 2014 5:33 pm

KSShooter, thank you so much for your tutorial in the HDMI dongle modification. I just finished stripping off (denude) the dongle and was looking at the numbering scheme for the pins. I saw the number 19 at one end and number 1 at the other end. flipping it over, I saw number 2 at one end and number 18 at the other end. So one side of the dongle goes from 19, 17, 15, ..., 3, 1 and flipping it over, the number goes from 2, 4, 6, ..., 16, 18. I see that you have created the short on the side where the numbers are odd. If that's the case, the next pin over from pin 19 is not 18, but 17. I will try my assumption and see if I can get this lapdock to finally work. Thanks again for the screen shots of your mod!

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