Have you ever been camping, and really wanted to play Galaga? Get ready for some good news. Behold the Retropie Tactical Field Unit!
This is a portable Raspberry Pi laptop/Retropie setup, enclosed in a waterproof case, similar to a Pelican case. The screen is mounted on the inside of the lid, and the other components are stored in foam pockets in the main part of the case.
Step 1: Gather Ye Materials
To build this project the same way I did, you will need the following items. I'm including links but obviously substitute as you see fit!
- Hard case, small, from Amazon Basics (Note: You can use a Pelican case, but make sure the inner dimensions are large enough for your display.)
- Raspberry Pi 3 B+, with Retropie on an SD card
- Raspberry Pi case
- 10.1" display, I used this touchscreen version
- Bluetooth keyboard
- Game controllers
- USB speaker
- Materials to mount the display in the case lid: (I got all these from Home Depot)
- Velcro strips 2" x 4"
- Aluminum sheet metal (approx 10" x 6")
- M2.5 10mm screws
- Cord to connect display to battery
Step 2: Pick N Pluck!
The Amazon case came with four layers of foam. There is an "egg crate" piece in the lid, that I removed and do not use for this project. There is also a thin, flat layer, which I saved to cover up the Pi, etc., to protect the screen when the case is closed. The two thicker layers are "pick N pluck" style, where the foam is perforated so you can create custom shapes. Here is what to do with these.
Top Layer : Lay out the Pi, the speaker, the power cord, and the folded up keyboard on the top piece of foam. When you have them arranged so they all fit, mark the locations with toothpicks. With the Raspberry Pi, make sure to leave some space for the USB and HDMI cords. Then, gently push into the foam and kind of pull it apart along your marked lines. Note: Try to leave at least a couple of squares worth of foam between pluck-holes, since single rows of foam can tear easily. Voice of experience.
Bottom Layer: For the keyboard cutout, pluck the same rectangle shape on the bottom layer as you did on the top so that pocket goes the full depth of the case. Also double down on the cutout for the power cord (right side). Lastly, if you use a battery pack, pluck a spot for the battery so it rests below the Pi and the speaker.
Step 3: Mount the DIsplay
The trickiest part was figuring out how to mount the screen in the lid. I played around with the idea of drilling through the lid and attaching screws to the metal standoffs on the back of the display, but I didn't like the idea of making holes in the case. In the end I decided to screw the display to a sheet of aluminum, and then use Velcro strips to attach the assembly to the inside of the lid.
I used a piece of cardboard as a template, and slathered the ends of the standoffs with red Sharpie ink, then placed the display on the cardboard. This gave me a pretty good imprint of where each standoff was. Then I taped the template to the aluminum sheet and drilled five holes. The display came with a bunch of different sized standoffs, so I had to play with the configuration to get it right.
Note: There is a place to attach the Raspberry Pi to the back of the display, if you want to use the display as a sort of tablet, but I wanted the Pi to be accessible so I didn't attach it to the display back. I did leave the LCD driver card in place, though one could remove it to make it easier to access. (The card has the display controls, brightness, contrast, etc., on it.)
Once the holes were drilled, I screwed the display to the aluminum sheet using the M2.5 screws. They fit right in and held it tight. Then, I stuck the "hook" Velcro strips on the aluminum sheet, with the "loop" strips on the inside of the case, et voila! I decided to mount the screen off-center, in the upper left corner of the lid, so that I could access the little buttons on the back of the screen with my pinky, and so there is room for the cords on the bottom.
Hint: Once I adhered the "hook" Velcro strips on the aluminum sheet, I attached the "loop" Velcro strips right on them and peeled off the back covering, exposing the adhesive. Then I just pushed the whole thing into the lid and let it sit for a few minutes. That way I didn't have to try and guess where to place the strips on the lid; they were automatically in the right spot.
Step 4: Assemble and Finish!
Once the foam is plucked, the screen is Velcroed, and Retropie is installed (I'm skipping that step since it is well-documented elsewhere), you can put it all together.
I placed the controllers under the keyboard, and ran the speaker wire between the top and bottom foam pieces. All that's left is to turn it on! For the first build, I used the power cord that came with the display. It requires 12V (although I tested it with a 9V supply and it still worked).
But, in order to make it a true "field unit" it needs a battery pack, right? So, I added a 12V battery pack, and all of a sudden, this unit is fully tactically mobile.
Note: The unit is a little top-heavy, with the monitor and aluminum plate in the lid. However, it does stand up on its own and won't tip over if it is on a level surface, such as a flat rock (or a table).
I plucked out a space for the battery pack underneath the power cord, on the lower piece of foam. I was a little worried the battery would heat up down there, but even after being on for 40 minutes or so it was not hot.
Well, there you have it. Thanks for reading - if you build one let me know how it goes!