Jimakos
Posts: 14
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Re: I made a Raspberry PI Laptop

Thu Oct 04, 2012 2:07 pm

Can anyone provide information about the supercap a member used?

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malakai
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Re: I made a Raspberry PI Laptop

Thu Oct 04, 2012 3:17 pm

Jimakos wrote:Can anyone provide information about the supercap a member used?

I think your talking about this post:

http://www.element14.com/community/grou ... ock-tricks

I followed the links and it say's Jay did it I followed another link that says this is his blog hope it helps please let us know if you find out anything

http://jeffsinventions.com/
http://www.raspians.com - always looking for content feel free to ask to have it posted. Or sign up and message me to become a contributor to the site. Raspians is not affiliated with the Raspberry Pi Foundation. (RPi's + You = Raspians)

Jimakos
Posts: 14
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Re: I made a Raspberry PI Laptop

Thu Oct 04, 2012 4:06 pm

I am creating a mini-housing from plexiglass with:
- micro-hdmi,micro-usb female inputs
- micro-usb(5V), standard usb(Data),hdmi male outputs
- hdmi hot plug/ground switch
in order to have a clean install of my raspi in my lapdock.
So i would like to include a supercap in my project, but i need
to know about the Farad value of the capacitor and the Ohm value
of the limiting current resistor. I didn't find anything in those blogs. :cry:

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johnbeetem
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Re: I made a Raspberry PI Laptop

Thu Oct 04, 2012 11:13 pm

selectnone wrote:
johnbeetem wrote:Here's my [element14] 'blog entry [on RasPi Lapdock HDMI cable work-around]: http://www.element14.com/community/grou ... ork-around
Very interesting, I look forward to seeing if you manage to find a way to add a full-off switch, I may actually mod my dock if that's possible.

While you're digging, maybe see if there's a reasonable method for disabling the power-dip on closing the screen? (The Pi gets power with the lid open/closed, but briefly turns off when you go from one to the other)
I managed to put in a tiny toggle switch to simulate plugging in an HDMI source. When the switch is off, the Lapdock is completely off and shouldn't drain charge as it did with my proof-of-concept solder bridge. I updated my element14 'blog entry to show details.

Instead of making changes to the Lapdock PCB, I found it easier and safer to hack into the cable that connects the Lapdock PCB to its Micro HDMI and USB ports. So I didn't do any investigation of the power dip. However, I did notice that there are some small components (at least one a transistor, I think) on the bottom surface of the Lapdock PCB near pins 29 and 30 of the tiny connector. Those carry +5V to the Micro USB port, so that's where I'd start looking. If you're lucky, +5V is always present on the Lapdock PCB when it thinks an HDMI device is attached, in which case one could play with the transistor's base or gate to keep it on. OTOH, it may be that opening or closing the lapdock turns off Lapdock's +5V for a couple of seconds, which would be much harder to track down. I'm not planning any further Lapdock exploration. As the Law states, "if you fool around with something long enough it will eventually break" and I don't know how close I am to that limit with Lapdock.

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Lob0426
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Re: I made a Raspberry PI Laptop

Thu Oct 04, 2012 11:52 pm

malakai wrote:Right now on ver.1 board rev 003. I am just backfeeding the power through usb port. But have tried every combination possible even feeding original power through adapter. Everything works just that game for some reason won't respond to keys I can't find anything else that is non responsive to touch pad and keyboard I am just bugged why that game has issues with it and wonder if eventually I won't find something else that does the same thing.
If you are using the stock USB hub link cable, it might be too long. This reduces your voltage. The connectors have some resistance also. Try to find a shorter cable 1ft (.3m) this will increase the voltage you are seeing at TP1/TP2 test points. If your cable is 3ft (1m) or more it is just too long. Even the 18" (.5m) cable that came with mine really dropped the voltage. Hardwiring one end of the cable will help also. You will always show a lower voltage at the test points as they are on the wrong end of the board.

Try to connect all of your USB devices to the hub as much as you can. USB drawing power from the RasPi ports lowers the voltage to the SoC and can cause resets. I have the hub on one USB (hardwired in) open USB port on the other (A female A dongle wire). I usually plug either my wireless keyboard/mouse there or just a USB memory stick. My WiFi dongle will work there but it drops the voltage a lot. My RasPi showed 4.25v at TP1/TP2 when I first back-powered it. Hardwiring both ends and having only 4" of wire now it is at 4.73v to 4.91v depending what I have plugged into the other RasPi USB port.

The Red connector is power only. All "Y" cables have that style of connection. The short end is always power only.

I hope this information helps you out.
here is my post about Back-Powering a RasPi!
http://www.raspberrypi.org/phpBB3/viewt ... 41&t=16473
512MB version 2.0 as WordPress Server
Motorola Lapdock with Pi2B
Modded Rev 1.0 with pin headers at USB

http://rich1.dyndns.tv/
(RS)Allied ships old stock to reward its Customers for long wait!

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malakai
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Re: I made a Raspberry PI Laptop

Fri Oct 05, 2012 1:06 pm

Thanks but I think after reviewing the code for penguinspuzzle it seems to search for usb keyboard in an off code and I don't think the Laptop reports a proper usb keyboard going to tinker and rebuild it if I can. Luckily the author left some commented out statements to search for keyboard hopefully I can get one to work my daughter loves the game.
http://www.raspians.com - always looking for content feel free to ask to have it posted. Or sign up and message me to become a contributor to the site. Raspians is not affiliated with the Raspberry Pi Foundation. (RPi's + You = Raspians)

OblongCheese
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Re: I made a Raspberry PI Laptop

Mon Oct 08, 2012 10:49 pm

Does anyone know where in the remote backwaters of Australia one could purchase such a device for less than the ridiculous sum of $300 AUD?

Parwana
Posts: 1
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Re: I made a Raspberry PI Laptop

Tue Oct 09, 2012 4:18 pm

Hi, I had some questions about the Raspberry Laptop. I already have a Motorola Atrix Lapdock and I thought this could replace my notebook.

Now to my questions.

Can I replace my notebook with this?
I use my Notebook mainly for programming in Java and other languages, I don't think there will be any problems here, but I want to be sure.

Does the RaspberryOS recognise printers?
I often need to print my code, so this is a must have for me.

Do the lapdocks USB-Ports work with this mod?
Can I plug in a 2,5" HDD, a Wifi Adapter in or any other device, without a seperate power supply.

I'm thankful for any help.

Sincerely
Parwana

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johnbeetem
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Re: I made a Raspberry PI Laptop

Wed Oct 10, 2012 8:13 pm

Parwana wrote:Hi, I had some questions about the Raspberry Laptop. I already have a Motorola Atrix Lapdock and I thought this could replace my notebook.

Can I replace my notebook with this?
I use my Notebook mainly for programming in Java and other languages, I don't think there will be any problems here, but I want to be sure.
You can use RasPi for programming, but remember that it only has 256 MB of RAM (which it shares with the GPU) and mass storage is SD card plus USB. This is fine for small-to-medium scale programming using the command line or a light-weight IDE, but a large IDE may require more resource than that, so YMMV. I suggest entering "performance" in the Google Search box on the RasPi home page.
Does the RaspberryOS recognise printers?
I often need to print my code, so this is a must have for me.
It should, but I've seen topics with people having printing problems. I suggest entering "printing" in the Google Search box on the RasPi home page.
Do the lapdocks USB-Ports work with this mod?
Can I plug in a 2,5" HDD, a Wifi Adapter in or any other device, without a seperate power supply.
Some work, some have problems. I suggest searching for specific devices.

RasPi software is evolving. It keeps getting faster and more reliable, but at this time IMO RasPi is still a developer board, which is part of the fun.

pygmy_giant
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Re: I made a Raspberry PI Laptop

Wed Oct 10, 2012 8:17 pm

This post should be called 'I connected my Pi to a Motorola Lapdock'.

biscuitehh
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Re: I made a Raspberry PI Laptop

Fri Oct 12, 2012 1:28 pm

I just thought I'd comment and say I finally have received all of my components to build one of these! I didn't splice any wires though, as I have the micro-USB going into one of the Raspberry Pi's USB ports and I have the Lapdock connecting to the raspberry pi's power port via one of it's USB ports. Now, without the power port being plugged in the Pi will boot for a second or two, then automatically reboot. Once I plug in the power port, it boots normally. When I close the lapdock, my light stays on in the raspberry pi, which I feel like has something to do with my Pi being powered over it's USB port. It's a revision 1 board, so I know there was some USB power freakery but I haven't noticed anything until now.

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malakai
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Re: I made a Raspberry PI Laptop

Fri Oct 12, 2012 1:45 pm

what revision do you have the polyfuse. It sounds like you do.
http://www.raspians.com - always looking for content feel free to ask to have it posted. Or sign up and message me to become a contributor to the site. Raspians is not affiliated with the Raspberry Pi Foundation. (RPi's + You = Raspians)

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johnbeetem
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Re: I made a Raspberry PI Laptop

Fri Oct 12, 2012 7:25 pm

biscuitehh wrote:... I didn't splice any wires though, as I have the micro-USB going into one of the Raspberry Pi's USB ports and I have the Lapdock connecting to the raspberry pi's power port via one of it's USB ports. Now, without the power port being plugged in the Pi will boot for a second or two, then automatically reboot. Once I plug in the power port, it boots normally. When I close the lapdock, my light stays on in the raspberry pi, which I feel like has something to do with my Pi being powered over it's USB port. It's a revision 1 board, so I know there was some USB power freakery but I haven't noticed anything until now.
To elaborate on malakai's comment, it does sound exactly like the behaviour people have seen when using a powered USB hub that provides upstream current. The USB standard prohibits this, but some hubs do it anyway. Lapdock's Micro USB plug does it by design.

Here is my understanding of what's happening: If you only have Lapdock's Micro USB port connected, Lapdock powers your RasPi through polyfuse F1 or F2, depending on which RasPi A (full-size) port is connected to Lapdock. F1/F2 is low enough resistance to start the boot process, but when it gets underway and RasPi needs more current the resistance of F1/F2 causes RasPi's 5V to drop and the boot to fail. But then the SoC's current needs drop so 5V comes back and the process repeats.

When you add a cable from one of Lapdock's USB A ports to RasPi's micro USB power jack, then Lapdock provides additional current though lower-resistance polyfuse F3 -- provided that Lapdock is open. In this case RasPi works fine. If you close Lapdock, its A ports switch off but the Micro USB port is still powered for charging an Atrix phone. This will cause your RasPi to continually reboot. If you look closely, you may see RasPi's green OK LED flicker every couple of seconds.

This is not good, because RasPi is drawing quite a bit of current from Lapdock's battery, and continuously aborting the boot process might corrupt your SD card though I'm not sure about that.

The modified version of RasPi rev 1 replaces polyfuses F1 and F2 with 0 Ohm jumpers, which avoids the F1/F2 problem. RasPi rev 2 discards F1 and F2 entirely, so it also avoids the problem.

EdwinJ85
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Re: I made a Raspberry PI Laptop

Wed Oct 17, 2012 8:24 pm

Hi guys, is anybody still selling these lapdocks for a reasonable price? Amazon wants £125 for them and the cheapest one on ebay is £80, CEX want £75 for a second hand one.

I really want to try this out but I'm not having much luck sourcing a lapdock.

Thanks!
Hello!

LurkAzusa
Posts: 8
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Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 2:55 am

EdwinJ85 wrote:Hi guys, is anybody still selling these lapdocks for a reasonable price? Amazon wants £125 for them and the cheapest one on ebay is £80, CEX want £75 for a second hand one.

I really want to try this out but I'm not having much luck sourcing a lapdock.

Thanks!
All4cellular has refurb and new lapdocks from $50 USD to $80. Search for Motorola Atrix Lap.
I just received a refurb and except for some wear on the box, the lapdock looks new.

EdwinJ85
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Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 9:42 am

Do they post to the UK?

EDIT- It appears they do! I just ordered a refurb for £65.49 - still a bit pricey but the cheapest option I have found at all online. The sad part is, delivery cost more than the lapdock itself.

That said, a raspberry pi + lapdock is still £300 cheaper than an ipad or microsoft surface, so I think I'll still come out on top.

Thank you very much for the help. Is there an easy place to source the cables I will need? I'm incapable of cutting up USB wires like the others have.
Hello!

LurkAzusa
Posts: 8
Joined: Thu Oct 18, 2012 2:27 am

Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 1:50 pm

EdwinJ85 wrote: Thank you very much for the help. Is there an easy place to source the cables I will need? I'm incapable of cutting up USB wires like the others have.
You may not need to splice any cables if you have a more recent version of the pi. Look to the right of the USB port and see if there are two fuses (F1 & F2) marked 0000 or if they are missing entirely, you won't need to splice. Just plug the USB cord into one of the ports to power and transmit data.

For the cables, search eBay for:

USB 2.0 A female to Micro USB B female adapter cable FF

USB A Male to USB A Male Adapter Converter M/M

HDMI Male to Micro HDMI C Female F/M Converter Adaptor

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malakai
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Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 2:25 pm

USB 2.0 A female to Micro USB B female adapter cable FF

HDMI Male to Micro HDMI C Female F/M Converter Adaptor

The only place to find these are China shops on eBay

http://www.ebay.com/itm/ws/eBayISAPI.dl ... 0928425953

http://www.ebay.com/itm/280761232832

If you find a better source please post it here.
http://www.raspians.com - always looking for content feel free to ask to have it posted. Or sign up and message me to become a contributor to the site. Raspians is not affiliated with the Raspberry Pi Foundation. (RPi's + You = Raspians)

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johnbeetem
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Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 6:23 pm

LurkAzusa wrote: For the cables, search eBay for:

HDMI Male to Micro HDMI C Female F/M Converter Adaptor
I think you want a Micro HDMI Type D connector. The HDMI Type C is Mini HDMI, not Micro.

I have not been able to find a Micro HDMI D female to HDMI A male cable, so I used a double-female Micro HDMI D adapter plus a standard Micro HDMI D male to HDMI A male. You can also get a Micro HDMI D female to Micro HDMI D male cable plus a Micro HDMI D female to HDMI A male adapter, or omit the cable if you have a way to secure the RasPi board.

A good source for cable/adapter links is Drew Fustini's 'blog post at element14: http://www.element14.com/community/grou ... -pi-laptop

Also, note that some HDMI cables -- both Micro HDMI and full-size HDMI do not implement the individual ground wires and this prevents an unmodified Lapdock from working. See my 'blog post at element14: http://www.element14.com/community/grou ... ork-around

LurkAzusa
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Re: I made a Raspberry PI Laptop

Thu Oct 18, 2012 11:10 pm

As per the comment by FLRich on Drew's topic, he used the hdmi adapter I showed. I haven't received mine yet, so I can't confirm definitely that it works, but you are right that D is micro and C is mini. However, as usual, ebay descriptions are often confusing and conflicting. It says micro C, which doesn't exist. I have seen a number of blogs and youtubes with people using that adapter, though.

http://www.element14.com/community/grou ... -pi-laptop

Syliss
Posts: 9
Joined: Sat Jun 30, 2012 10:46 pm

Re: I made a Raspberry PI Laptop

Sat Oct 20, 2012 3:03 am

I am thinking of selling my pi and lapdock on ebay or the like. Have all the cables and what not too. Just not finding enough uses and may just try to get a tablet instead. If you think you may want it let me know.

LurkAzusa
Posts: 8
Joined: Thu Oct 18, 2012 2:27 am

Re: I made a Raspberry PI Laptop

Mon Oct 22, 2012 4:42 pm

LurkAzusa wrote:For the cables, search eBay for:

HDMI Male to Micro HDMI C Female F/M Converter Adaptor

I can confirm that this does work wonderfully.

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ActionHank
Posts: 6
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Re: I made a Raspberry PI Laptop

Tue Oct 23, 2012 9:02 am

I'm having difficulties finding a reasonably priced lapdock here in Ireland/UK :( Anyone here thinking about selling one by any chance? :)

JonB
Posts: 220
Joined: Tue Nov 29, 2011 9:26 pm

Re: I made a Raspberry PI Laptop

Tue Oct 23, 2012 12:11 pm

*Thinking*, yes. Go on, tempt me. Say a LapDock complete with connecting Y cable, HDMI and all adapters.

FlipBumWalla
Posts: 10
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Re: I made a Raspberry PI Laptop

Tue Oct 23, 2012 3:13 pm

I just got this converter
microHDMIfemaleHDMIfemale2.jpg
microHDMIfemaleHDMIfemale2.jpg (10.94 KiB) Viewed 5778 times
microHDMIfemaleHDMIfemale.jpg
microHDMIfemaleHDMIfemale.jpg (11.42 KiB) Viewed 5778 times
last night and I confirmed that it works! For me, it works out well since I can use any HDMI cable I have for the TV and stuff.
Next, I am going to "build" the USB cable. I am also going to look around for other options for an HDMI cable.
This converter does not fit "nicely" into the cradle on the lapdock. I plan to grind the converter down a little to shape it differently. I will likely remove parts from the cradle as well. If I do that, I'll try to remember to get some pictures.


Micro HDMI socket D type Female to HDMI 1.4 A type Female adapter convertor:
http://www.ebay.com/itm/160884802942?ss ... 1497.l2649

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