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  • Author Author: fustini
  • Date Created: Date Created
  • Views 4740 views
  • Likes 3 likes
  • Comments 19 comments
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Raspberry Pi lapdock tricks

fustini

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:

image

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.

image

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:

image

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):

image

 

Cheers,

Drew

  • Detailed photos of how the super cap is connected.  Jay Hopkins from my hackerspace, Pumping Station: One, has the negative lead of the super cap going to ground on the micro USB connector shell.  The positive lead is soldered to 30 guage wire which runs to a power switch.  The other side of the power switch is connected to the positive side of the power input poly fuse on the bottom of the Pi. 

     

    Jay charges the super cap with the Pi on and no SD inserted.  It is a 1.5 F super cap.  More photos at: https://picasaweb.google.com/117542001281850354871/NERPMeeting8# 

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    image

  • Opps. In my haste I didn't give it a chance to boot completely. Tonight I had OpenELEC running from Berryboot, and was streaming video from the internet via a network cable.  So the Pi was working with the lapdock closed.  This would have been great if the Pi didn't reboot when you open the lapdock.  This all worked with my previous configuration, using the dual mirco usb cable.

     

     

    So I think With your configuration and the "fresher" Pi (I am jealous)image you could hook up your small LCD and use your mini keyboard powered via the lapdock.

  • in reply to Former Member

    Interesting, I'd be curious what TP1/TP2 voltage reads.  Sadly, I don't currently have a micro HDMI coupler anymore and wanting for another to come from China - oy!

  • Wow! That capacitor mod looks to be quite useful. I have a usb battery pack, and will use that for now.

     

    As a side note on this. I had my Pi connected to the lapdock, and also composite out to my tv. When I closed the lapdock the Pi was still powered, and displaying info on the tv. It looked like it was trying to reboot, but only went so far and stopped. I'll have to look at that again when I have more time.