o19
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Re: I made a Raspberry PI Laptop

Wed Nov 21, 2012 4:16 am

Okay, if that works, I should also be able to power the Pi from the cell phone charger I used before and just use the data portion of my y-cable. Just to see if it's a power issue. Unfortunately I'm a bit short on supplies here, since I'm just finishing up an internship in the new world and already packing stuff to move back to good old Europe :) That's also why I'm not too keen on buying additional things to bring it up.

But this is a lot of options now and I'll check it out and let you all know on Monday, once I'm back from a weekend trip. Thanks a lot...

itimpi
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Re: I made a Raspberry PI Laptop

Wed Nov 21, 2012 9:35 am

o19 wrote:Okay, thanks for the suggestions. I won't be able to check anything before Monday, but now I have at least a few things to try. Backpowering is not an option for me, since I have one of the older boards. At least not at this point in time, with some of the other options still present.
I used the PiPass modification on one of my older boards so that I could back-power and avoid the need for the Y cable.. I did this in preference to shorting out the F1/F2 Polyfuses because at the time it was not know what the implications of that were.

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terrycarlin
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Re: I made a Raspberry PI Laptop

Wed Nov 21, 2012 5:12 pm

johnbeetem wrote:
terrycarlin wrote:I have run into a problem when trying to back power the rpi from the dock. I get low voltage between tp1 and tp2. Down around 4.1v. I run into the typical problems of low voltage like repeating keys. When I power the rpi from a PSU, the voltages come up to 4.8 or so and things work fine. There is nothing on the rpi usb buss except the connection to the dock. I am wondering if my usb cable is giving me heartburn. It is a 12" male A to male A. I have an adapter to convert from the dock to the male A.
Do you have a rev 1 or rev 2 RasPi? The original rev 1 RasPi USB A ports have 140 mA polyfuses F1+F2 which have a large voltage drop at 500 mA. Normally they'd prevent back-powering from working at all, but at best they'd give you a large voltage drop. I replaced my F1+F2 with 1A single-blow fuses, with a 50 mV drop when back-powering. Later rev 1 RasPis replaced F1+F2 with 0 Ohm jumpers and rev 2 RasPis don't have F1+F2 at all, so in these cases F1+F2 are not your problem.

My Lapdock has 5.02V at its USB A ports. TP1-TP2 is 4.91V -- this is after the 50 mV drop across the 1A fuse which means I'm getting a 60 mV drop over my USB cable and adapter. My cable is a 25 cm A female to micro B female suggested by Drew Fustini's element 14 'blog entry (link) and available from eBay (link). I have a short generic A male to A male adapter at the RasPi end.
I removed F1/F2 and replaced them with a bit of wire a while ago. I have a similar cable set for USB. My male A to male A is only 12" long, but the cable seems a bit skinny. I am thinking it is not made well. These cables are pretty hard to come by. I ordered it from China and it took weeks to arrive here in the states. I have ordered another one and hope it does better. BTW, the USB ports do power a girtboard without any issues so I am pretty sure I didn't mess up too badly when I removed F1/F2.
If it ain't broke, take it apart and see how it works.

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johnbeetem
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Re: I made a Raspberry PI Laptop

Thu Nov 22, 2012 12:55 am

terrycarlin wrote:
johnbeetem wrote:
terrycarlin wrote:I have run into a problem when trying to back power the rpi from the dock. I get low voltage between tp1 and tp2. Down around 4.1v. I run into the typical problems of low voltage like repeating keys. When I power the rpi from a PSU, the voltages come up to 4.8 or so and things work fine. There is nothing on the rpi usb buss except the connection to the dock. I am wondering if my usb cable is giving me heartburn. It is a 12" male A to male A. I have an adapter to convert from the dock to the male A.
...

My Lapdock has 5.02V at its USB A ports. TP1-TP2 is 4.91V -- this is after the 50 mV drop across the 1A fuse which means I'm getting a 60 mV drop over my USB cable and adapter. My cable is a 25 cm A female to micro B female suggested by Drew Fustini's element 14 'blog entry (link) and available from eBay (link). I have a short generic A male to A male adapter at the RasPi end.
I removed F1/F2 and replaced them with a bit of wire a while ago. I have a similar cable set for USB. My male A to male A is only 12" long, but the cable seems a bit skinny. I am thinking it is not made well. These cables are pretty hard to come by. I ordered it from China and it took weeks to arrive here in the states. I have ordered another one and hope it does better. BTW, the USB ports do power a girtboard without any issues so I am pretty sure I didn't mess up too badly when I removed F1/F2.
If you have a good Ohmmeter, check the resistance of your 12" cable's Vbus wire. My cable plus adapter gives me a 60 mV drop, so assuming my RasPi is consuming 500 mA that's 120 mOhm. That would be hard to measure with a standard Ohmmeter since the probe resistance would dominate.

In your case you've got a 900 mV drop, so that's 1.8 Ohm at 500 mA. That should be measurable. I attach my probes to safety pins if I need a sharp probe to get into Micro USB or Micro HDMI connectors.

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hop
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Re: I made a Raspberry PI Laptop

Thu Nov 22, 2012 9:46 pm

That looks pretty good, I can't wait to see if the RasPi develops into a full computer system. :D

cjan
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Re: I made a Raspberry PI Laptop

Sat Nov 24, 2012 12:21 pm

caps lock key white light bright random, anyone have this issue?

FlipBumWalla
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Re: I made a Raspberry PI Laptop

Tue Nov 27, 2012 3:24 am

cjan wrote:caps lock key white light bright random, anyone have this issue?
Sorry. I don't have that problem.

o19
Posts: 38
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Re: I made a Raspberry PI Laptop

Thu Nov 29, 2012 4:51 am

Hey,

spent another couple of minutes on my "no keys" problem. Since the week has been pretty busy up to now I didn't manage to organize new parts yet, but I tried a slightly different setup using a phone power supply and only the data portion of my y-cable. As I expected I got the same results as before. So it's either the cable (as mentioned above I'm pretty sure I didn't mess up the pins, but it might just be a poor cable) or my keyboard is dead.
An Atrix might actually help, or some known-to-work cable combination. :) Anyone able to supply one of those in the Bay Area in exchange for a coffee? Otherwise I'll just go and try to find some other cables at nearby stores or wait until I'm back in good old Europe and have access to all the tools...

Best, Jan

o19
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Re: I made a Raspberry PI Laptop

Fri Nov 30, 2012 1:48 am

Okay, quick update. Looks like something is wrong with my dock. I borrowed a keyboard at work and it works. Not only if it's directly connected to the Pi, but also when it's connected to the docks hub and the dock is connected to the Pi using my y-cable. Same thing for the touchpad.

So if I didn't miss the part where I have to turn on the lapdock keyboard somewhere it seems to be broken. I'll probably just let it go until I'm back home... 40$ is still a steal for the screen, the hub and the battery...

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johnbeetem
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Re: I made a Raspberry PI Laptop

Fri Nov 30, 2012 2:20 am

o19 wrote:So if I didn't miss the part where I have to turn on the lapdock keyboard somewhere it seems to be broken. I'll probably just let it go until I'm back home... 40$ is still a steal for the screen, the hub and the battery...
Bummer. I wonder if the you can turn screen brightness up and down by holding down a "fn" key and pressing the '~' and '{' keys. Screen brightness is handled within the lapdock, so this would tell you if the keyboard is completely dead or it's the USB connection to the keyboard.

Might just be a loose cable in the Lapdock. The Lapdock is pretty easy to disassemble to get at the main circuit board, but watch out for the 12V battery voltage.

o19
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Re: I made a Raspberry PI Laptop

Fri Nov 30, 2012 5:46 am

That was actually a good idea to track it down further. Controlling the brightness didn't work as well, so I'll use the coming weeked to have a look inside the dock below the keyboard. I already had removed the cover towards the rear once, but didn't see anything. Anyway, it's a great exercise...

o19
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Re: I made a Raspberry PI Laptop

Sat Dec 01, 2012 4:31 am

Success! After closing the connector for the ribbon cable of the keyboard unit (keyboard side), it works! I just don't know how long I'm going to use it this way now, since the dock is so modular, that I actually might want to build something less laptop-like from the parts :) Thanks a lot for all the help.

This helped a lot as well: http://www.techrepublic.com/photos/crac ... ainer;b60b

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The Ardent Serpent
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Re: I made a Raspberry PI Laptop

Sat Dec 01, 2012 7:44 pm

I assembled an RPi computer system created strictly from plug and play parts (i.e. no soldering/splicing). I'm happy to say it came to a success.

I've posted a parts list and schematic for those who are interested:
http://www.ardentserpent.com/#12

Image

Full size pic:
http://www.ardentserpent.com/images/rpicomputing.jpg

1HzCoder
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Re: I made a Raspberry PI Laptop

Sat Dec 01, 2012 8:39 pm

Ordered the lapdock and cables ect. over the weekend.
This is my kind of hacking. Has anyone thought of running a twisted pair of greenwires from the unused data pin outputs on the power micro usb around to the data terminals of one of the usb outputs? Looking at the schematic and enlarged photos it looks like it could be done. That is if you can solder that small, something I can only do on my best days. All hacking would be inside the Pi case, hopefully making a neater job on my "FrankenPi", and leaving all usb outputs free. It's not even born, yet I have named her.
What do you think?
Einstein once said you don't really understand anything until you can explain it to your Grandmother

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johnbeetem
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Re: I made a Raspberry PI Laptop

Sat Dec 01, 2012 10:13 pm

o19 wrote:Success! After closing the connector for the ribbon cable of the keyboard unit (keyboard side), it works! I just don't know how long I'm going to use it this way now, since the dock is so modular, that I actually might want to build something less laptop-like from the parts :) Thanks a lot for all the help.

This helped a lot as well: http://www.techrepublic.com/photos/crac ... ainer;b60b
That's terrific! Thank you for the TechRepublic link -- I added it to the Wiki (http://elinux.org/RPi_Screens#Motorola_Atrix_Lapdock).

Bobknopfler
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Re: I made a Raspberry PI Laptop

Sun Dec 02, 2012 9:13 am

Hi o19, can you expand on the fix a little for me please. I'm having a similar problem but the atrix is brand new so I think a fault is unlikely. I've tried adjusting brightness and volume without success. Everthing works fine with a usb keyboard plugged directly into the rpi. Is there a way of testing the lapdock?

Thanks.

o19
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Re: I made a Raspberry PI Laptop

Sun Dec 02, 2012 11:30 am

Bobknopfler wrote:Hi o19, can you expand on the fix a little for me please. I'm having a similar problem but the atrix is brand new so I think a fault is unlikely. I've tried adjusting brightness and volume without success. Everthing works fine with a usb keyboard plugged directly into the rpi. Is there a way of testing the lapdock?

Thanks.
Sure. I bought my Atrix second hand, but it came in the original packaging. With the first attempt and a y-cable based on the sketches in this thread I got HDMI and power working right away. Only USB data seemed not to work. To try if your issue is indeed similar to mine, I'd try to plug the USB keyboard into one of the female USB-A ports on the lapdock. If that gives you data over the y-cable, you might have the same issue.

In my case the blue ribbon connector in this image (http://www.techrepublic.com/photos/crac ... hotopaging) wasn't connected properly. To get there I just disassembled the dock following that entire slideshow. Once I'd gotten there and reconnected it, I followed it again, this time using the << button. :)

Everything inside the dock is fixed with screws or good quality connectors. The connectors use different mechanisms to keep the cables in place, but it should be easy to figure out how they work. If you found the proper way, you won't need to apply brute force. The only tools I used were a screwdriver and a pair of tweezers (for the connectors).

The connector right of the tweezers in this image (http://www.techrepublic.com/photos/crac ... photo-roto) should be the 12V power connector. You might want to disconnect it first.

AND: You'll most likely void your warranty. I went for it, because I bought mine as "used" and for cash. If you can go for an RMA, that might be the simplest solution...

Bobknopfler
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Re: I made a Raspberry PI Laptop

Mon Dec 03, 2012 12:10 am

Excellent advice.

A standard usb keyboard plugged into the lapdock doesn't work either, so it looks like my Y cable is no good for the data connection. Maybe the cheap cable was a bad choice. I'll order another asap and make sure it's a female micro to male A type.

Thanks again for your help.

Bobknopfler
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Re: I made a Raspberry PI Laptop

Tue Dec 04, 2012 7:24 pm

Hi o19,

Just a quick question for you.....

If you connect your lapdock only to to the rpi through the hdmi and provide power to it, can you adjust the volume or brightness using the lapdock keyboard? I can't, which I'm guessing might suggest a fault on the unit?

Thanks again,

Nick (frustrated !)[*]

Chris1975
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Re: I made a Raspberry PI Laptop

Fri Dec 07, 2012 8:46 pm

What are the commands to enable/disable ethernet? Thanks in advance.

stubz151
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Re: I made a Raspberry PI Laptop

Fri Dec 07, 2012 9:52 pm

is there touch support? and any sound

Chris1975
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Re: I made a Raspberry PI Laptop

Fri Dec 07, 2012 10:13 pm

stubz151 wrote:is there touch support? and any sound

No touchscreen. Sound works well though.

Chris1975
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Re: I made a Raspberry PI Laptop

Fri Dec 07, 2012 11:21 pm

Chris1975 wrote:What are the commands to enable/disable ethernet? Thanks in advance.

Nevermind.I found them. :lol:

Devfarse
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Re: I made a Raspberry PI Laptop

Sat Dec 08, 2012 1:57 am

Newark has a good supply of Pis from what I have seen over the last few days. I ordered one and all of the necessary connectors for about a 6 foot standoff from the Pi and got a new Atrix lapdock off of amazon for $80. I only have a laptop and no external monitor so I had been looking for a separate monitor and USB keyboard so this think is a great fit for me and worth it for the nice form factor and battery.

I will be getting a rev 2 model B so I will try to backfeed power through the USB A connector but if I have problems I will just use the micro USB and make the Y adapter. Sometimes it is vague, but am I correct in assuming that the micro USB can't be used in host mode?

brainchill
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Re: I made a Raspberry PI Laptop

Sat Dec 08, 2012 8:12 am

This is cool for the pi but its also a really cool application for a generic keyboard video solution for around the datacenter ... thanks!

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