problems setting raspberry pi up with lapdock 500

[LAK132]

I managed to identify all the large chips on the internal board, I have a list of all of them here

The ones that look important are:

Chrontel CH7034B HDTV/VGA/LVDS Encoder:

This chip appears to be the one that drives the LVDS screen and the VGA output on the lapdock.

explore EP9351 HDMI receiver:

This is the chip that receives the HDMI 1.3 signals from the connected device and converts those signals into something the Chrontel and the audio controller can understand. This chip also has HDCP 1.4 which may be the source of our problems.

Texas Instruments M430F5521 MSP430:

This chip seems to communicate with the explore chip over I2C and the hub over USB, which may also be the source of our problems

[lak4]

First and foremost you guys rock. I am trying to get the screen of my lapdock 500 to work. Does anyone know if it will work without the pi connected to the USB? I am just seeing if I can get the screen to work and have a wireless keyboard hooked up. The power light flashes when I plug the HDMI into the pi.

[lrosellpardo]

I bought a lapdock 500 for my raspberry pi from ebay (because I believed it was no difference between Atrix lapdock).
When I get the package, I plugged it and nothing happened then I began to search information on google and I found this thread the sad true.

So I decided to disassemble it and buy a lvds controller from ebay and my lapdock has reborn.

The result it's dirty but works (poor man laptop).



PD ( Meegopad T01is connected, I use my raspberry pi as tv server)

[LAK132]

Nice! Can we get a link to the LVDS controller you used and maybe some close up shots of how it is all connected?

[lrosellpardo]

Closer images.:

http://imgur.com/a/nKRDq

and very good quide to take it apart from thanks to Robpol86.com.

https://imgur.com/a/UDZs7#on1EG

[leonbollerup]

Hi,

What LVDS controller did you buy.. ? .. looking at ebay it seems there is quite a few options.

[LAK132]

Does anyone have access to a Webtop Travel Adaptor? (http://www.amazon.com/Motorola-Travel-A ... 005J373HG/) if we can crack one of them open, it might tell us how the devices communicate with the phone

[leonbollerup]

Sadly not, but i'll be happy to finance one if it can help the cause.. i have a few of these docks and would like to use it either with some rPi or windows phones.

Also checked the nexdock .. but there is some time until they are ready to ship (if they get funded that is)

[LAK132]

It would certainly identify what the Motorola devices use to communicate, but it may not be very useful beyond that. Gonna need some VERY high quality images of the insides if you do get one

[isetter17939]

I have the Raspberry PI3 and a Motorola Lapdock 500. I have read as much as I can find on getting the RPI to drive the Lapdock. I have tried at least a dozen different connectors between the lapdock and RPI3 with no response from the lapdock. Just about run out of options aside from making this post for some help.

[LAK132]

I managed to find a dirt cheap Webtop connector, should be arriving this week. At this point this connector is everyone's last hope :/

[LAK132]

I got my hands on that adapter, very interesting little thing. The HDMI is a straight pass through, but the USB connection has some weird stuff on it

I managed to make a schematic of the board: http://i.imgur.com/a4jjHm4.png (note this may not be 100% correct. The lower USB has D- and ID swapped, the transistors may not all be transistors though I have listed their markings)

Here are some pictures of the board: http://imgur.com/a/NGaSK

If someone is able to work out how this works and what all the components are that would be great!

[Shun_di12]

I've just managed to get hold of a lapdock 500 pro and I am trying to hook it up to my Macbook Pro for testing purposes (I intend to hook it up to my Raspberry Pi at a later date).

When I connected the HDMI and the usb via adaptors I didn't get anything on the lap dock (as mentioned before, make sure that the 5v doesn't back feed into the computer as this can damage it and can apparently kill MacBooks!)

So I started messing around with the usb adaptor and I found that whenever I shorted the D+ (green cable) to the sense pin with the usb unplugged from the macbook, the screen on the lapdock would fire up briefly for a couple of seconds and then go off again. I though that was a bit weird, but every time I shorted these two pins with the usb cable unplugged it would work for a few seconds.

So after messing around for a bit longer, I found that if I plugged the usb cable into the Macbook while the screen was on, it stayed on! Plus the mouse and keyboard also work with multi touch.

So my current procedure is this (NOTE, I don't have sense pin grounded, as it doesn't seem to work):

Make sure that the HDMI is plugged into the computer and the lapdock and the usb is plugged in.
Open Lapdock
Short D+ to Sense pin
Plug usb cable into computer
Lapdock is now working

I have tried this several times after closing the lapdock lid and it works every time.

If the cable is plugged into the computer before hand, shorting D+ and the sense pin doesn't bring the screen on.
So if either D-, D+ or Ground (or a combination of) is connected to the computer then the shorting trick won't work. This is what I want to find out next and see which cables needs to be disconnected.

If I can find that out, all I need to then is make a momentary switch that when pressed, breaks that connection at the same time as shorting D+ to sense. Then when the button is released the usb is connected again and D+ and sense are no longer shorted. That would give me a much more user friendly procedure:

Make sure both cables are connected at both ends
Open Lapdock
Press Button/Release button
Lapdock turns on.

If/when I get this working, I'll try it out on my Raspberry Pi.

[LAK132]

Great find Shun! Looking back at the Webtop connector I have now, that seems about right!

[lumsdot]

I made my own lapdock

From uk ebay got a lp101wx1 1280 800 ips 10 inch lcd panel for £20, it was a pull from a laptop.

From china i got a lp101wx1 hdmi driver module for £15

Put both into a cheap ipad folio case, and vola a cheap lapdock

Just velcro everything together

Works great

Ps watch out for sellers advertising lp101wx1 panels, but send you a compatible item, in general it is compatible but not IPS, it should say lp101wx1 on the back of the panel

[Shun_di12]

Thanks Lak. Your comment about the D- and the sense being swapped gave me an idea. I tried shorting D- and sense the same way that I did with the D+ and that worked as well.

For further investigation I cut the usb cable and connected it back together with bullet crimps so that I could choose which wires were connected. Currently, I was unable to get the screen to come on if the usb cable was connected when I shorted the D+ or D- to the sense pin. So I tried different combinations of D+,D- and ground connected to the Macbook when shorting the pins.

It turns out that whichever pin (D+ or D-) I was shorting mustn't be connected to the Macbook. For example, D+ is disconnected from the Macbook, I can then short D+ to sense and then quickly re-connect D+ to the Macbook and the lapdock works. So ultimately, all I need to do is to create a momentary switch that breaks the D+ (or D-) connection to the computer while at the same time shorting to the sense pin. When the switch is released the D+ is connected back to the lapdock. I assume the webtop connector is doing something similar.

I'm sure this can be achieved with a mechanical switch or some kind of Arduino setup.

Also, I noticed that when I plugged the USB in to the Macbook, I didn't need the ground connected for the screen/keyboard/trackpad to all work. I suppose the ground is only for the voltage while D+ and D- can communicate as a pair on their own.

[Radon_22]

Sorry to necromance here, but has anyone came up with a solution? Thought about cannibalizing a lapdock 100 I have, but wanted to verify before I tear it down.

[Ddensa]

Hi, the solution from the gentlemen above works perfectly. I created a prototype board with a micro and a standard usb, with a switch in between doing the shorting. It works very well, the only thing is that you need to do the shorting, in my case I do it manually through the switch.

[mauimania]

Hi, the solution from the gentlemen above works perfectly. I created a prototype board with a micro and a standard usb, with a switch in between doing the shorting. It works very well, the only thing is that you need to do the shorting, in my case I do it manually through the switch.

Hi, would you share the information about the prototype board you built?
I am not good at electronics.
Thanks in advance.

[qnhoang81]

I was able to get this working on the pi with a prototype switch. If there is enough interest, I may make some available for purchase. I was also able to make the connection to my Mac as well as a second monitor.

https://www.youtube.com/watch?v=-a3qS45Z_ro

[apakezdodik]

I was able to get this working on the pi with a prototype switch. If there is enough interest, I may make some available for purchase. I was also able to make the connection to my Mac as well as a second monitor.

https://www.youtube.com/watch?v=-a3qS45Z_ro

hi.can you post the schematics? thanks

[qnhoang81]

I don't have a schematic of the setup, but the video should explain what I did (if you can stomach the poor quality of the video). Basically I connected all the pins of a micro USB female breakout board to a micro USB male breakout board (simply grounding the sense pin will not work... I tried). The female end obviously connects to the lapdock. I'm not 100% sure the HDMI needs to implement DDC/CEC grounding, but my guess would be that they did not change this from the Atrix Lapdock, which requires it. So for the micro HDMI side, I have a female micro HDMI adapter to male HDMI. I added a female to male HDMI cable for good measure to make sure one of them implements the pin 17 grounding. Plus the adapter is short, so it'll be good to have this extension anyhow so that you have some room to connect your micro USB cable for the keyboard and mouse.

All of that is required to keep the dock on. To turn on the screen, you'll need a way to short the sense pin to the VCC pin momentarily. I created a switch to do this after the Pi is powered up.

You also need to put the proper config setting in the /boot/config.txt to make sure autohotplug is on and the right hdmi group is set.

Let me know if this makes sense. If not I can attempt to draw it out, but that may be even uglier...

[apakezdodik]

I don't have a schematic of the setup, but the video should explain what I did (if you can stomach the poor quality of the video). Basically I connected all the pins of a micro USB female breakout board to a micro USB male breakout board (simply grounding the sense pin will not work... I tried). The female end obviously connects to the lapdock. I'm not 100% sure the HDMI needs to implement DDC/CEC grounding, but my guess would be that they did not change this from the Atrix Lapdock, which requires it. So for the micro HDMI side, I have a female micro HDMI adapter to male HDMI. I added a female to male HDMI cable for good measure to make sure one of them implements the pin 17 grounding. Plus the adapter is short, so it'll be good to have this extension anyhow so that you have some room to connect your micro USB cable for the keyboard and mouse.

All of that is required to keep the dock on. To turn on the screen, you'll need a way to short the sense pin to the VCC pin momentarily. I created a switch to do this after the Pi is powered up.

You also need to put the proper config setting in the /boot/config.txt to make sure autohotplug is on and the right hdmi group is set.

Let me know if this makes sense. If not I can attempt to draw it out, but that may be even uglier...

if you can draw it it will be nice,im a visual type

i want to use my lapdock as a secondary monitor of my laptop and with my phone (which not supports mhl ) so i want to hook up the hdmi side on a chromecast and the micro usb side to the phone with a micro-usb c adapter.so as far as i can get ill need a hdmi micro female-hdmi male cable and a micro usb female-micro usb male cable which i have to cut in half and solder a momentary swith between the vcc and sense pin?

[qnhoang81]

This setup worked with the laptop. I used it with my Mac and it works great.

In regards to the cable, you'll probably need to strip the connector end of the female micro-USB as most likely there is not a "sense" wire connected to the ID pin.

I'll see what I can do about the diagram.

[apakezdodik]

This setup worked with the laptop. I used it with my Mac and it works great.

In regards to the cable, you'll probably need to strip the connector end of the female micro-USB as most likely there is not a "sense" wire connected to the ID pin.

I'll see what I can do about the diagram.

i found this:

https://www.aliexpress.com/item/Cablecc ... 0.0.YDPhou

if i put a momentary switch on it ,i just need this and a micro hdmi female to hdmi male cabele and im good?