Portable Raspberry Pi

16/07/2012

This project is a portable Raspberry Pi computer.

It uses standard off the shelf hardware. The LCD is a low cost TFT monitor used in car reverse camera. The monitor has a video input but the supply is 12v. This needs to be modify to accept 5v from the batter pack. The battery pack is a standard portable USB charger.

 

Modifying the LCD Monitor

The monitor requires a 12v input but the battery pack only gives out 5v. Inside the monitor there is a 5v regulator. This need to be by bypass and connect straight to the 5v line. The red supply wire is removed from the plug and soldered directly onto the 5v line.

 

Tapping 5v from the Power Pack

The 5v for the monitor need to be tapped from the power pack. The simplest way is the splice it in. The joint is then covered with insulating tape.

 

On a Laser Cut Base

 

Part List

  • Car reverse LCD monitor – ebay
  • Mini wireless keyboard – Amazon
  • USB Power Pack – Amazon
  • Laser cut base – SK Pang Electronics

 

Disclaimer

Modifying the LCD monitor at your own risk. This mod removes any over voltage protection to your monitor. Any incorrect voltage applied may damage the monitor.

 

 

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50 Responses to Portable Raspberry Pi

  1. Daniel Jonsson on 21/07/2012 at 00:44

    Brilliant! I want one of those. :D

    • Chris Johnstone on 22/03/2013 at 04:41

      At the risk of repeating any previous statements…….could the power not be supplied from a small 12 volt supply and regulated down? Just a thought. Although I suppose there may be a weight issue…..Hmmmmm….now theres a project.

      Great set up. Nice base.

      • admin on 22/03/2013 at 08:36

        You can use a 12v battery and step down circuit to 5v but the 5v USB battery charger are readily available and that is what I’ve chosen to use.

      • Shaun Ellis on 01/03/2014 at 20:12

        Or why not use 8 alkaline AA batteries to power the screen

  2. Amir on 21/07/2012 at 19:47

    that’s amazing!!! I will make one of these.

    • Daniel Jonsson on 21/07/2012 at 20:44

      Me too, I just ordered all necessary parts for it. :)

  3. David Simpson on 22/07/2012 at 21:25

    how easy is it to read things on screen

  4. admin on 22/07/2012 at 21:28

    It is quit difficult as the screen only has a resolution of 320 x 234 pixels. This project is really a proof of concept. I am looking into a 7″ screen with HDMI input but they are a lot more expensive.

  5. David Simpson on 22/07/2012 at 21:35

    what i thoght wish they hurry up and make the lcd’s and the dsi port work

  6. David Simpson on 22/07/2012 at 21:37

    i had thoght about the tv gogles that a so a few years back and thoght about them

  7. David Simpson on 22/07/2012 at 21:39

    Video Glasses i ment

  8. Thomas Newby on 23/07/2012 at 11:00

    Excellent proof of concept. I have been looking around to see if this was possible, and I’m glad you took the time to share.

    One small question though; how long does the battery last? I’m guessing not very long?

    Thanks again

  9. admin on 23/07/2012 at 11:08

    The battery only last about 2.5 hours with no power saving features turned on. The battery pack is a 5200mAh.

  10. David Simpson on 23/07/2012 at 14:01

    i have a battery pack i got on ebay it takes 18650 li-ion batterys and ups the 3.7 volt to 5 volt has built in charger etc i have 4 5000mah batterys for a total of 20,000mah

  11. Felix on 01/08/2012 at 11:10

    You soldered on an additional capacitor next to the screw, that fixes the board. Is that needed?

    • admin on 01/08/2012 at 11:27

      No additional capacitor was soldered.

      • Felix on 01/08/2012 at 11:40

        Ok, strange. Because that’s the ONLY difference between your and my monitor.

  12. Khivar on 01/08/2012 at 20:36

    Hello admin,

    I was looking for a small LCD screen powered by 5V and found nothing until I found your project, that’s awesome ! There are some things I don’t understand and I have some beginner questions if I may :

    1) Could you link the exact screen on Ebay because there are a lot of them with the same specs/looks and I want to be sure to get the exact same one.

    2) On the photo you already rerouted and soldered the red cable to the capacitor leg, right ? That’s all there is to do ?

    3) “The battery only last about 2.5 hours”. I’m really far from being an electronic expert but isn’t that strange ? The Raspberry Pi consumption doesn’t exceed 500ma, the bluetooth dongle for the keyboard can’t exceed that either, that would mean the LCD screen consumption is 1A which would make a minimum of 5 watts. Seems a lot for a screen that size, all the screens on ebay indicate < 3 watts and that's with 12V, since here we bypass the buck regulator the consumption should be even lower. Am I missing something ?

    4) If the battery lasts 2.5 hours, that would make 2A consumption, the battery pack is rated at 1A. Isn't that dangerous ? How come the battery doesn't heat up and die with that many current ?

    Thanks in advance ;)

  13. admin on 01/08/2012 at 23:07

    1) http://www.ebay.co.uk/itm/270737270914

    2) Yes, the red cable is the 5v line from the USB power pack. Check the capacitor leg is the 5v line. Do this mod at your own risk.

    3) Although the battery pack is 5200mAh you will never get this in real life due to loses in the system. Also the system shuts down before all the power is used up.

    4) Your calculated value is different then the real value.

  14. Marijan on 07/08/2012 at 15:53

    Is it possible to connecet mobile phone LCD ? doesn’t matter touchscreen/ordinary, I’m just curious

  15. david simpson on 07/08/2012 at 22:43

    atthe moment they is a port for it but they are no drivers or code written for it as of yet

  16. crookedmouth on 27/08/2012 at 04:18

    Hi,

    I have a rear view lcd and I’m looking to bypass the regulator. Is the red 5v line connected to the positive or negative? My lcd has no legs on the regulator and I am afraid I got an unusable one.

    Thanks.

  17. admin on 27/08/2012 at 08:34

    The red 5v connect to the positive but it looks like you have a different model of the LCD. I would not do the mod as if you get this wrong you will damage your LCD.

    • crookedmouth on 27/08/2012 at 11:57

      Thanks for the quick response, I understand the risk. I hope that I will be able to use a multi-meter to make sure that I am hitting the right connection. Everything looks like the same set-up of your LCD just, no legs.

      Either way once I get there I will post my result.

  18. crookedmouth on 27/08/2012 at 22:30

    Sorry to double post but I was wondering how you identified the 5v line?

  19. David Simpson on 27/08/2012 at 22:49

    i dont know how he had done it but my self i would check the voltage across the legs of the caps or find the voltage regulator

    • crookedmouth on 28/08/2012 at 00:31

      Thanks for the reply, since there is no power to the LCD can I still get the voltage or will it be in ohms?

    • crookedmouth on 28/08/2012 at 04:26

      Thanks for the reply, I’m not sure if I can get the reading off the multimeter if there is no power going to the LCD. Using a simple equation I believe that I have two 5v resistors inline just like the photo above but I’m not sure which one to connect to.

      I may have no choice since one of the joints in the first one seems to straddle two circuits?! One “leg” is nicely spaced away but by nicely spaced I mean it is 2mm away. The actual leg I need to solder is under a millimeter. I’m holding off until I can get a multimeter and some soldering practice.

      Thanks again.

  20. chris on 24/09/2012 at 19:11

    i like the setup and wish i could find an acrylic base plat like that on mount my pi onto.
    any suggestions?

  21. curx on 26/09/2012 at 09:11

    this is cool, but i’d like to make an in-car-entertainment system out of the raspberry pi. with touchscreen display and stuff, hehe

  22. Phil on 04/10/2012 at 16:09

    Thanks for the hot tip re. the 5V hack to the TV – I have now stuck one of these displays onto my synth, works great, and it’s USB bus-powered!

  23. dancer42 on 10/11/2012 at 02:47

    I am vary interested in your design and had some thoughts,what might the next step be?
    my thought is why not a 10 or 20 Raspberry Pi Beowulf cluster steal the kb touch pad and screen and maybe the voltage regulation circuitry + battery from the laptop. how much folding @home could i do for under $500 and a little over $100 for each 3 added nodes!

  24. JRcash on 18/11/2012 at 21:19

    Where can i buy the acrylic? Cant find it in the shop :/

  25. whip on 30/11/2012 at 16:00

    i really like the setup/orientation of your project. do you know where i could purchase a laser cut base for my project that is similar to yours?

    thanks

  26. admin on 30/11/2012 at 16:13

    Sorry the acrylic is not available to purchase.

  27. Cryptid7 on 12/12/2012 at 00:22

    How did you install the keyboard I am having trouble

    • admin on 12/12/2012 at 23:23

      The keyboard is a wireless one from Amazon. It comes with a dongle which just plug into the USB port. No software driver to install.

  28. 1234 on 26/12/2012 at 17:33

    what are the dangers associated with bypassing the 5v regulator?

    also how stable is the 5v that comes from the battery pack?

  29. M1C4HTRON13 on 29/01/2013 at 22:04

    Instead of spliting the usb cable would it be posible to power off the 5v GPIO pin?

    • giulio on 21/02/2013 at 01:30

      Amazing project!
      I think it is possible to powerup the monitor even with GPIO pins, that means it is not necessary to modify the micro usb cable.
      I already have this LCD monitor, and have like to know if it is possible to modify to work with just 5V
      http://www.upsled.com/print_page_p1009
      Is it?

  30. Pyrofer on 20/03/2013 at 19:52

    I had already bought this exact LCD to use with my Pi, thanks for showing how to do the 5v mod as that saved me a little work.
    Did you know this LCD has a touch screen hidden away?

    If you remove the front plastic cover the LCD has a resistive touch screen applied, the 4 pin connector is fixed to the main LCD connector but you can separate it and use the touch screen.

    Hackaday had a post on it.
    http://hackaday.com/2013/03/15/enabling-an-unused-touchscreen-overlay-on-a-consumer-lcd/

  31. Jyppedi on 23/04/2013 at 16:23

    Hello
    I have this http://dx.com/p/7-wide-screen-tft-lcd-headrest-car-monitor-with-remote-control-set-480-240px-41213 screen and i would like to know can i get this work same way.

  32. quinn on 19/06/2013 at 00:17

    I was wondering if you have a larger usb battery with two outputs you could power the pi with one and the monitor with the other?
    If so, how much battery life would it get?

  33. mschausprojects on 28/07/2013 at 18:05

    This looks like a super fun build. I took another route to get to using my Pi and programming faster using a lapdock:
    http://mschausprojects.blogspot.com/2013/07/create-raspberry-pi-laptop-with.html

  34. luke on 29/07/2013 at 17:42

    hello, is there a safe way to open the LCD case (I have the same as you) without crashing it? :) thanks.

  35. Nuria on 20/09/2013 at 14:37

    Hi, my lcd wasn’t exactly like yours, but I managed to find the point where there was 5v and I connected the red wire there, everything worked right, thanks for the tuto ^_^

  36. terry on 20/09/2013 at 19:55

    Thanks for cool hack! I also tried the 5v USB hack on mine but board is slightly different. I ended up with only a white screen though. Anyone else had this problem?

  37. taragor on 31/10/2013 at 18:40

    I´ve tried to build it too, but i didnt find the screen, so i took anotherone. The result is,after overriding the 5v controller; that the screen is just very short onand showing the picture(ca 0,1s) and then it turns off again(ca2s) and then it turns again on.

    anyone an idea to help me??

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