UPDATE: The original model was optimized to slice and print well on my printer, which has a 0.35 nozzle. But a friend had trouble slicing this for his 0.4 printer due to the very thin walls of the enclosure. So I have uploaded alternate versions of the case and surround .stl files that have a 2mm wall thickness. (The original is 1.85mm) The same brackets can be used with either design. After slicing, it is recommended that you inspect the tool path output in the gcode before you print, to ensure adequate wall strength.
The Raspberry Pi makes a great portable linux machine, but it is hard to manage without some kind of display. Now the 7" touchscreen makes it easy to see what the Pi is doing. There were a few good case designs already, but none of them allowed easy access to change the SD card. I also had problems slicing some of the existing designs to fit onto my 200mm printer.
This project was inspired by http://www.thingiverse.com/thing:1082431 and http://www.thingiverse.com/thing:1164446, but is a brand new design (not a remix) hand-crafted with OpenSCAD.
1.) Full access to (almost!) all Raspberry Pi 2 or 3 Model B ports, including the SD card slot. The case intentionally covers the USB power input port on the Pi so that you don't accidentally try to use it. Instead, USB power goes into the port on the PowerBoost to charge the battery and/or run the Pi from wall power.
2.) Room inside for a large battery. I am using a 6000 mAH battery pack.
3.) 3D printable without supports - short bridging required. Can be printed on a 200mm print bed. To avoid warping, let printed parts cool before attempting removal from print bed. Total print time ~ 8 hours.
4.) All cables exit through the side or rear of the enclosure to allow it to sit smartly on edge during use.
The circuit I used was published by Adafruit. I used the element14 7" Touchscreen and the Adafruit PowerBoost 1000C lipo battery charger with a Raspberry Pi 3B, along with a 6000 mAH 3.7v lipo pack. You will also need to provide a SPST or SPDT slide switch, some velcro, and a few small (#0 or M3) screws to hold everything together.
NOTE: If you attempt to turn on the Raspberry Pi without a formatted (and uncorrupted) OS loaded onto the micro SD card, the monitor will not turn on. If the display doesn't work with your Pi, first make sure you have inserted a good micro SD card before you disassemble the unit.
For additional build instructions, see the excellent Adafruit page describing the original project:
Designed to eliminate overhangs and minimize bridging gaps, but may still be a challenge to print cleanly. To avoid warping, let all parts cool completely before attempting removal from the print bed.
1.) Print the case, the screen surround, and a pair of brackets.
2.) The display controller PCB is factory mounted to the back of the touchscreen using four metal standoffs. We will not need the standoffs and they interfere with the other components inside the case, so replace them with the screws provided with the touchscreen. (You can use just two screws in opposite corners and save the other two screws to mount the Pi if you are short on hardware.)
3.) The brackets have a set of larger holes on one leg. Use these larger holes and four short M3(?) screws to connect the surround and both brackets to the back of the screen. Be careful that the screws do not sink deep enough to damage the back of the touchscreen!
4.) Use the other two screws provided with the touchscreen to mount the Raspberry Pi inside the printed case.
5.) If you have a SPDT switch with three terminals, cut one of the outer legs off to avoid short circuits. This makes it into a SPST switch. Solder the two remaining legs of the switch to the EN and GND on the PowerBoost 1000C. It doesn't matter which way you solder the switch, but it will determine whether you slide the switch toward the front or rear of the unit to turn the power on. (The case is designed to accept the switch in either orientation.)
6.) Use two of the jumper wires from the Touchscreen kit to connect 5v and GND on the video controller to pins 2 and 9 on the Pi GPIO connector, as per the Adafruit circuit diagram. Also connect the ribbon cable from the touchscreen to the Display port on the Pi.
7.) Cut one end off of the remaining two jumper wires and solder them into the 5v and GND outputs from the PowerBoost 1000C. Connect the other ends to pins 4 and 6 of the Pi GPIO connector, as per the Adafruit circuit diagram.
8.) Use two small screws to mount the PowerBoost into the case.
9.) Connect the lipo battery to the PowerBoost 1000C and use velcro or double-sided tape to secure the battery to the bottom of the case. Make sure the battery is secure and is not in position to be punctured by the screws you are about to install...
10.) Use four small wood or sheet metal screws to attach the case bottom to the angle brackets, taking care not to damage any internal components - especially the battery. The screws should self-tap into the small holes in the angle brackets.
Always remember to shut down the Pi through the menus or command console and let the operating system close down before you turn off the power with the slide switch. Failing to do so may corrupt or damage your SD card.