Raspberry Pi lapdock tricks

11 Sep 2012

I learned a couple tricks for the Atrix lapdock last night during our Raspberry Pi / embedded interest group at my hackerspace. One of our members, Jay, had a super capacitor hooked up his Pi:

Why would he do this? Well, the power supplied from the Atrix lapdock drops for a few seconds when the lapdock lid is closed. The super cap keeps the Pi running in the meantime.

You can click on these pictures to enlarge, but there probably still isn't enough detail to know how to hook it up. Therefore, I'm hoping to get the complete details and will post here.

In the meantime, here's another trick Jay came up with where he uses a small USB battery pack to act as a buffer:

The charging input for the battery pack is connected to the lapdock while it's output goes to the Raspberry Pi (or Android MK802 mini-PC in these pictures):

Cheers,

Drew

Top Comments

Former Member over 11 years ago +1

Surgery free supercap mod for pi/lapdock I wired two 2.5 volt 1.0F supercaps in serial, cut the end off a usb plug and soldered the cap to the appropriate red & black wires on the usb plug. Some hot glue…

Former Member over 11 years ago

Surgery free supercap mod for pi/lapdock
I wired two 2.5 volt 1.0F supercaps in serial, cut the end off a usb plug and soldered the cap to the appropriate red & black wires on the usb plug. Some hot glue and heat shrink to make the package somewhat secure and with this charged and plugged into the usb port there's enough power to avoid the black out when closing the lid of the lapdock.

I didn't think it worked at first but I left it plugged in to a usb port overnight and now it seems to work fine. It appears to re-charge fairly quickly now, I don't know why it took all night at first. I'm planning on just leaving it plugged into the pi.
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Former Member over 11 years ago in reply to fustini

Did you ever get an answer to this? It seems to me you should be able to charge the cap during ordinary operation. In other words just leave it on all the time.
I'd like to avoid the power off/on situation with the Lapdock.
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Former Member over 12 years ago in reply to johnbeetem

Changing the keyboard to "us" worked for me. Couldn't find the pipe key |. now its where its supposed to be
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johnbeetem over 13 years ago

By default, RasPi is configured for a Great Britain ("gb") keyboard. I first used my RasPi with a Logitech K120 keyboard with a USA layout, using the Debian "Squeeze" distribution. I had to switch the "gb" layout to "us" using the instructions at the RasPi TroubleshootingWiki

When I hooked up my Lapdock, the "us" layout was correct and I didn't have to change anything. I don't know if all Lapdocks have the keyboard configuration, so you may need to play around with the setting.
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fustini over 13 years ago in reply to Former Member

Ah good question. I've not used it recently but I'll check the next time I do. johnbeetem is very knowledgable about the lapdock so he may know.
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