Author Topic: The Cubietruck chronicles - Chapter II: Lapdock days  (Read 6027 times)

Offline actkk2000

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The Cubietruck chronicles - Chapter II: Lapdock days
« on: October 30, 2014, 12:56:49 am »
Hi there!  :D

This is the next chapter of http://www.cubieforums.com/index.php/topic,3147.0.html

To test CT with an Android image and as for benn's advice I downloaded this one from cubieboard.org:
http://dl.cubieboard.org/software/test/ct-android-factory-VGA.img.gz

But I wanted a 1080p HDMI capable image, then I found this one in the same dir:
http://dl.cubieboard.org/software/test/android_cubietruck_1080P.img.tar.gz
I tried it on a full hd capable monitor and worked right out of the box as well.

At that time I was also finishing to adapt a Motorola Lapdock for Atrix to my other project:
http://forum.lemaker.org/forum.php?mod=viewthread&tid=8307&fromuid=1602




Since CT board was not fixed to any case or box, I decided first to attach CT alone to the Lapdock for a try.
I saw this post I realized it will be possible for CT to be used with a lapdock as well:
http://www.cubieforums.com/index.php/topic,1366.0.html

Also these adapters worked for CT without any modifications:
http://www.dx.com/p/micro-usb-male-to-female-extension-data-cable-black-20cm-123738#.VE1jBHl0yHs
http://www.dx.com/p/micro-usb-female-to-usb-male-adapter-black-172524
http://www.dx.com/p/cy-hd-156-bk-micro-hdmi-female-to-hdmi-male-adapter-cable-for-tablet-pc-cell-phone-black-20cm-279467#.VE1jIXl0yHs

And I plugged the CT USB power cable to one of the USB ports on back of the Lapdock.
The only inconvenience was that when the lid was closed, power on the USB ports also got cutted and CT was shutted down without any warning...
Just after open the lid againt CT started, meaning Lapdock USB ports remained off when the lid was not fully open...

Here some pictures while testing the stand alone mode (click to enlarge):





I also tried to simplify connections by using just one USB cable like the one described on Adafruit:
http://www.adafruit.com/blog/2012/09/10/cables-adapters-for-the-atrix-raspberry-pi-laptop/
For that I bought a cable designed for PSP with the advantage that it already has a 2.5mm plug that will fit on CT:
http://www.dx.com/p/usb-data-and-charging-cable-for-psp-3000-2000-1000-110cm-length-28732#.VFGu7Hl0yHs
And also a mini USB adapter for the USB port:
http://www.dx.com/p/usb-a-male-to-mini-usb-5-pin-female-adapter-26785#.VFGuynl0yHs

That would allow a project to use the USB port designed for Atrix cellphone, which when the lid is getting closed it just cuts power for a second and starts again once fully closed.
This is not an inconvenience for a cellphone, but without any batteries CT still was shutted down and restarted as soon as the lid touched the keyboard.

To keep the power for that (actually less than a) second I considered Super Capacitors, as described here:
http://www.element14.com/community/community/raspberry-pi/blog/2012/09/11/raspberry-pi-lapdock-tricks
http://www.zprod.org/zwp/making/supercapacitor-raspberry-pi/

But first I tested the cable, with no luck. CT seemed to not have power enough to work, as soon as it started to boot, it just power off inmediatly.
Then I added a USB extension cable modified for my other project, with the 5V line cutted to avoid backpower on the CT USB ports (as also is explained on Adafruit video):



If this worked, eventually I would do the modification directly to the PSP cable.
But didn't work either. The only way it worked was plugging the mini USB portion directly to CT OTG port, seems that reinforced somehow the power needed to boot.

That was not the expected because in that way USB port data for cellphone on the Lapdock was cancelled and the keyboard and pad wouldn't work either.
Probably was a cheap cable, then after trying different configurations with no results, eventually I gave up.

But I was surprised when I also attached a Sata disk and it worked without problems, just with the power provided by the USB port on the back of the Lapdock:





As long as the lid remained open, it wouln't be any problems. But then CT wouldn't act as real laptop, right?  ???

So finally I decided a final test, adding CT to my other project, and using the original external power source that I bought along with CT.
It's a 5V 2A USB charger like this: http://www.goodluckbuy.com/hp-universal-5v-2a-power-adapter-usb-charger-for-tablet-pc-.html
And since I have a HDMI switch with 3 connections, I've got one spare for CT...

The only problem will be the keyboard and pad, because I have a USB swith with only two connections.
But for testing purposes I could unplug Raspberry Pi USB cable and use it on CT.
Other way was plugging a USB mini mouse to CT, and also a mini keyboard that I wasn't using anymore.



So here is a video of the "three amigos" working together... (click to enlarge)



It was a short stay, because during that period something happened that would change CT fate forever...
But that story, is for the next chapter...
http://www.cubieforums.com/index.php/topic,3163.msg20835.html#msg20835

See you soon! And thanks for reading this! :)

« Last Edit: November 02, 2014, 02:24:23 am by actkk2000 »