Motorola Lapdock Atrix with the Pi

[bhavikp94]

Hi, I am trying to connect up a Raspberry Pi to the Motorola Atrix so I can use it for the screen, keyboard, touchpad(mouse) and USB ports.

I have found the following guides so far:
http://www.instructables.com/id/Raspber ... /?ALLSTEPS
and
http://rpidock.blogspot.co.uk/2012/05/r ... pdock.html

I was hoping if anybody else has managed to connect the Pi to the lapdock in a much more simple way avoiding the need to cut open wires or trim adapters to make it all fit.

Thanks for your time.

[fdufnews]

The Atrix lapdock was designed to interface a Motorola phone not a Raspberry Pi so it is not surprising you need to hack a bit the lapdock. You should also notice that the modification are quite limited

[procount]

I have 2 of the 10" Atrix lapdocks (with the pull out cable) that my boys use with their RPI B's and 1x 11" Atrix 4G lapdock (with the swivelly bit at the back) that I connect to my B, B+ or 2B. For both types of Lapdock the connections are the same and I have not needed to trim any connectors.

I use a micro HDMI female to Micro HDMI male extension lead (about 6") which connects to a micro HDMI socket to fullsize HDMI male plug adaptor that goes into the Pi.
Then I use a Micro USB female to micro USB male extension lead (abotu 6") which connects to a micro USB female to fullsize USB male plug adaptor that plugs into the Pi.

Using the micro extension cables means the sockets are quite small and do not need cutting or adapting to fit onto the lapdock connectors. This combination is a little more expensive because you need 4 parts, but they are more readily available.

If you are using an RPI A or B, the Pi can be "Back-powered" through the above USB cable.

If you have a B+ or a 2B then you need to power the Pi though its micro USB power connector.
I have tried 2 ways: 1) using a standard USB to micro USB charging lead connected to one of the 2 USB output ports of the lapdock, and 2) using a USB split charging cable conencted to the micro USB output of the lapdock (i.e. a micro USB female that splits into 2 cables with micro USB male connectors on each end). Only one of the connectors can be used for data, but both can supply power. I have not found it necessary to cut the power leads in the USB cable to the Pi USB data ports on the B+/2B, but maybe I should - I'm not sure if this stresses any of the components, but it seems to work as is. I'll probably buy another micro USB extension cable to do that by cutting it in half and then rejoining the data and gnd lines.

I think I bought all of my components off ebay in the UK for quick delivery (~£10), although I had to buy the split charging cable from China, but it came quite quickly. I could probably provide links if you need them.

[Steve Drain]

The two links in the OP are probably a poor guide now. First, the supply of of suitable connectors is much wider and probably cheaper than those earlier times. Second, the features of the current Pi change some of the assumptions. The summary from procount is excellent for the situation now, and I have linked the Pi in just the way he suggests.

However, if you want to get ambitious, you could look at this:

http://kappa.me.uk/raspberry_pip4.htm

[procount]

Your Pip4 is so cool - I love it! Well done.

I have often thought of doing something similar, but with the larger Pi2 and a small HDD included. so I would have to strap mine under the lapdock somehow. That would have been easier with the smaller lapdock as it has the pull out cable to just plug in, but the base unit is not very flat. The larger lapdock has a nice flat base, but less convenient connectors. Ho hum.

[Steve Drain]

I have often thought of doing something similar, but with the larger Pi2 and a small HDD included.

Using the A+ with the Lapdock has a couple of advantages as well as size. It can be back-powered through USB, which reduces the complication of cables, and it uses significantly less current, which is good for a portable. There is already a hub in the Lapdock and if you need a network connection there is a WiFi dongle [1] or very cheap USB-Ethernet adaptor. You do not get the speed advantages and memory of a B2, but I use RISC OS and this is not very significant. An A2 would be interesting.

IThe larger lapdock has a nice flat base, but less convenient connectors. Ho hum.

It also has a nice flat lid. Early on I mounted a Pi to the lid with magnetic paper, so it could slide to a convenient position. Many people mount theirs with velcro.

[1] There is no support for WiFi dongles in RISC OS, but there are various way to overcome this, none completely satisfactory.

[moony]

Hi there,

I'm a happy RaspberryPi + Motorola Atrix Lapdock user, but I'm missing touchpad settings, because the touchpad is too slow. There's a GUI tool for this, called "gsynaptics" which is just a transitional package, without a command afaik.
There's another one for KDE, but I unwillingly want to install the whole KDE-environment..

[start78]

Using a lapdock with a Pi ZeroW is fun for retro gaming but hasn't got enough performance for pretty much everything else.

A Pi 3B starts up but randomly reeboots. Most likely because the lapdock doesn't provide enough power. Voltage doesn't seem to be the problem because the low voltage sign never shows up.

Has anyone already tested a Pi 3A+ with an Atrix Lapdock? Does it even need less power than a Pi 3B? I know: 2,5A power supply is recommended for the Pi 3A+.

Additional question: is it possible to power the Pi 3A+ through the USB port (like with the Pi Zero) or do i need the same adapter cable i'm using for the Pi 3B?

[procount]

I gave up using anything later than a RPi 2B on a Lapdock due to such power constraints.
And after much use, some columns of the keyboard stopped working reliably, requiring multiple hard keypresses to get one character on the screen.
I haven't got a 3A+ to test, so I can't help on that score.

[start78]

I now have tried using the Lapdock with a Pi3A+. It boots up and i can even sort of use it but sometimes it crashes just like the Pi3B. Usually if i try anything needing wifi.

Example: Booting to Raspbian Desktop and starting the Browser works, but as soon as i try to open a page the RasPi reebots ~3 out of 5 times.

Voltage doesn't seem to be the issue, because i have never seen the flash symbol on my Lapdock. But i have no way of checking the current provided by the Lapdock.

Would it be possible to add some kind of buffer circuit to my adapter cable that handles the few current peaks when the RasPi needs more power? Maybe a simple capacitor could do the trick? Sorry, not very experienced in electronics...

[procount]

I remember reading some posts along time ago about adding Super-Capacitors to allow the RPi to ride through some of the power disconnections which happen when rebooting the Atrix, so maybe one of those would help. But it depends on the extent and duration of the (assumed) power surge.

EDIT: I think it was the older grey Lapdock (Bionic?) that had the power disconnection issues, rather than the slim black lapdock (Atrix?)

[Mortimer]

I have an Atrix lapdock, and in my experience:

RPi 2B worked reliably, powered from the lapdock, even without a USB power lead connected from the lapdock to the RPi power inlet. I.e. powered entirely via backfeed power down the USB data connection. However this only worked if using the USB socket on the back of the lapdock for the wifi dongle, and not using the USB ports on the RPi itself for anything.

RPi 3B worked reliably as long as the lapdock had two USB connections to the RPi, the data one from the uUSB connector on the flap of the lapdock plus one for power from the main USB ports on the lapdock to the power inlet of the RPi. Again the wifi dongle had to be on the other USB port of the lapdock. Connecting a single USB thumb drive directly to the RPi was OK, but any more was asking for trouble.

RPi 3B+ would not work reliably from lapdock power alone. A mains PSU connect to the RPi power inlet was required to keep the low Voltage warning from appearing.

[cjan]

I gave up using anything later than a RPi 2B on a Lapdock due to such power constraints.
And after much use, some columns of the keyboard stopped working reliably, requiring multiple hard keypresses to get one character on the screen.
I haven't got a 3A+ to test, so I can't help on that score.

same keyboard issue here, so drop it to closet 2 or 3 years ago, poor Atrix

[procount]

@Mortimer - i think I would concur with your findings, although I didn't test so extensively.

A mains PSU connect to the RPi power inlet was required to keep the low Voltage warning from appearing.

One word of warning to others - IF you do this, remember NOT to power the Lapdock with it's own power supply at the same time as powering the RPi from another adaptor. I forgot and did this once when the Lapdock battery was getting low. BAD mistake. The first time I blew a hole in the Microcontroller of the Atrix and let the blue smoke out. The second time I smacked myself around the head a few times for being so stupid! No visible effect this time, but the result was the same. It's easily done. Maybe powering the RPi by a suitable battery powerbank instead of an adaptor would be a better solution if you think you might do this by accident.

same keyboard issue here, so drop it to closet 2 or 3 years ago, poor Atrix

Yes, the keyboard reliability is a real shame, but it can still be used with an external USB keyboard, but it sort of defeats some of the purpose of having the lapdock.

[start78]

Maybe one of the many usv solutions could do the trick. But most of them cost more than i payed for the 3a+ and the lapdock combined...

Anyone able to make a scetch of a simple one-adapter-cable-with-integrated-capacitor solution that theoretically should do the trick?

Attached is a picture of the adapter i'm using right now.

[moony]

I've used the RasPi 2 and the thin black Motorola Lapdock for Atrix some time ago. I've made the custom cable, as seen in the post before. Everything was running wel. I've only had power issues, that lead to reboots, in the moment when connecting a WiFi dongle while the Pi was already running.
A (super)capacitor with about 1 Farad or more, low ESR (!), and at least 5V, could help. If you want to buffer via capacitor, place the capacitor as near to the Pi as possible, i.e. if it's in the cable: At that end of the cable that goes into the Pi micro USB. Background is: cables have a resistance and also act a bit like inductors, the longer the bigger are those effects..

[start78]

what about connecting it to the gpio port instead of building it into the cable?

would this one work?
https://www.amazon.de/Goldcap-Kondensat ... ensator+1f