This week’s blog post comes from Mike, one of Dayton’s many makers. Since Pi Day was Tuesday, a Raspberry Pi project seemed appropriate!

When I originally bought my Raspberry Pi, I had primarily thought of using it as a Retro Pi; I figured it would be fun to play the games of my childhood with my kids. Pretty quickly though, I became interested in the other possibilities of the Pi, and I started playing with the Sense Hat, turning it into a media center, and a few other projects that are out there for the Pi. But, what I discovered is that, if I wanted to work on it away from home, it wasn’t very convenient. So, I decided to make it more portable.

Oooo, fancy!

First things first, I needed a container for the electronics. A family trip to the local antiques mall yielded up a very nice, wooden cigar box. With that acquired, I started looking around for a tutorial online for what I wanted to do. Adafruit has a good outline for this, as well as several YouTube makers. Ultimately, I came up with the following layout for the electronics:

 

The Pi consumes around 1-2 Watts under normal use.  This requires about ½ Amp from the Li-ion cells. With two Li-ion cells (2.2 Ah each), the Pi should last around 8 hours. I haven’t tested this yet, though.

Additionally, the LCD screen consumes about 5 Watts. This requires about 1.4 Amps from the Li-ion cells. This may be pushing capability of TP4056, I really don’t know. That is why I don’t recommend charging batteries while using the screen. The TP4056 likely can’t handle the amperage required to do both simultaneously. With four Li-ion cells (2.2 Ah each), the LCD screen should last around 6 hours. I haven’t tested this.

Total cost < $200
Total value: Priceless!

There are a few quirks to this design. First, the Pi and the display run from two separate power supplies, which is the reason for the two toggle switches. I suspect that I would be able to combine them so that everything runs from one supply. Also, the display controller I bought doesn’t allow me to dim the display backlight, but advanced users might be able to do this from the Pi via pulse width modulation.

Parts List

  • Enclosure (cigar box)
  • LCD screen (x1)
    • 10.1” diagonal, 1280×800
  • LCD Controller board (x1)
    • Caution: make sure you buy the correct one for your display!
  • TP4056 battery charging circuits (x2)
  • XL6009 boost converters (x2)
  • Raspberry Pi 3
  • Toggle switch (x2)
  • 18650 lithium-ion cells (x6)
  • HDMI cable, 1ft (x1)
  • Zip ties (x6)
  • Adhesive backed zip tie mounts (x6)
  • USB keyboard and mouse
  • Nickel strip (~ 1ft)
  • Speaker wire (red/black) (~ 2ft)
  • Wire (black) (~ 2ft)
  • microUSB plug, stripped (x1)
    • To power RPi
  • 12V Power plug (+ inside), stripped (x1)
    • To power LCD board
  • microUSB power supply, 5V, 2A (x1)
    • For charging
  • Various nylon standoffs w/ screws (~ x14)
  • Package of RPi heatsinks
    • For Pi and 12V boost converter

Tools Required

  • Multimeter
    • To set boost converter output and general troubleshooting
  • Soldering iron
  • Wire cutters
  • Wire strippers
  • Small screwdriver set
  • Hot glue gun
    • Holds TP4056s to box
  • Superglue
    • Holds standoffs to box
  • Drill, jigsaw, and file/rasp.
    • For cutting access holes in enclosure
    • For making screen holder blocks

6 Comments

  • […] boxes, however, remain. [Mike] found a very nice antique cigar box, and made something unexpected, he put a Raspberry Pi in it and made something close to a laptop. Into the lid goes an LCD screen secured with wooden blocks, while in the body of the box goes the […]

  • stephan says:

    nice project

  • R. Hatheway says:

    You have a nice project. I saw it on Hackaday.com
    I am putting a single board computer into the case of a dead H.P. Pavilion laptop.
    I found the Chinese LCD controller can run well on less than the specified 12 volts. Try that.
    I got a USB keyboard that fits the original keyboard space in the Pavilion. Yours would look good with the keyboard inside the box.
    Yours would be nice if the keyboard had a built-in touch pad.
    I am building mine so I can change between a Raspberry Pi for Linux, a Intel Compute Stick for Windows or an RKM MK802 television device for Android.
    (not all at the same time).
    Mine is getting a USB to IDE controller to run the CD/DVD player.
    I am using the original battery and wall charger.

    Have fun with yours,
    Russ

  • Vojťák says:

    What is the reason not to charge the Li-ion cells while in use? Charging voltage is never higher than 4.2 volts, so step-up converters (and Raspberry Pi behind them) would be okay with that. And TP4056 can deal with that too.

    • Mike says:

      Vojt’ak,

      Well, I can’t find specifically where the manufacturer of the board does or does not recommend charging under load. The documentation I can find is either lacking or in Chinese. So, to be safe, I don’t recommend it. I think the board can only pass through 1 A, which is not enough to both run the display and charge the pack.

      Stephan,
      Thanks!

      R. Hathaway,
      Thanks! I may try to rebuild this and fit in a small keyboard. However, I like typing on the full-size keyboard better!

      Thanks,
      Mike
      [project builder]

  • Garamondo says:

    you might want to try:
    using a Raspberry Pi Zero W (10$)
    and a bluetooth keyboard With touch pad
    https://www.amazon.com/gp/product/B01N94X5O5/ref=ox_sc_act_title_4?ie=UTF8&psc=1&smid=A14G2WQFKDF07O
    this will fit in your cigar box.
    my LCD controller though rated at 12v, runs just fine on 9v and only draws 200ma
    its a 7″ screen from ebay – roughly 30$ including shipping (screen,controller with hdma,vga & composite, and separate menu button board)

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