The Raspberry Pi. Its a $35 computer the size of a credit card. Being very small, its great for its portability. However, this is usually the problem as it is hard to make it portable.
Over the past year and a half, I have worked with my friend (KM4BLG) to create a portable raspberry pi. Recently my High School got a Makerbot Replicator, so I was able to 3D print an enclosure for the new portable raspberry pi.
The criteria for my portable raspberry pi was to make the pi, screen, and audio jack fit in one enclosure.
Step 1: Gather Materials
You will need the following materials to build this. Most can be found on Amazon.com.
- Raspberry Pi (B+ or 2)
- Small LCD (used for a car backup cam) http://amzn.com/B00965GJIC
- (Optional) Small Keyboard/Trackpad http://amzn.com/B003UE52ME
- (Optional) Wifi Dongle
- (Optional) Bluetooth Dongle
- Ribbon Cable (5 Wires)
- Audio Jack (3.5mm)
You will also need:
- Soldering Iron
- Solder (I use 40/60 Pb/Sn Blend Rosin-Core)
- Screwdriver (Phillips and Flat Head)
- (Optional, kinda) 3D Printer
- Glue (Hot-Glue and/or Super-Glue)
Step 2: Tear Down Screen
The 5″ screen easily comes apart, just use a small flat head screwdriver to pry open the enclosure. There are 2 pieces of plastic that snap together to form the enclosure. It shouldn't break when you disassemble it!
Inside, you should find the LCD with a board attached to the LCD by a ribbon cable. 2 connectors are attached to the board; one is the controller (2 wires) the other is the display input (4 Wires).
You can go ahead and remove the controller and cut the display cable. make sure to leave some wire so that you can solder to it!
There are 4 Wires:
- Power + (Red)
- Ground – (Black)
- AV1 (White)
- AV2 (Yellow)
The White wire will override the Yellow wire if there is a signal present.
The Data sheet on the screen says that it takes 6-32VDC. So, now you might be thinking, “Well darn, how are we gonna power it?” Well, the data sheet is incorrect. First off, if you put 24V or more into it, the screen gets fried, and if you put 5V into it, it still works! Inside the screen lies a linear voltage regulator designed to provide a constant 5V output.
This is very convenient, because we can power the screen directly off the GPIO header on the Pi!
Step 3: Solder Ribbon Cable onto Pi
After doing some testing and looking up data sheets, I managed to figure out the pinout for the AV connector. On the board, there are 5 solder points that hold the 3.5mm jack in place.
We will solder onto 3 of them (Video, Audio L & R)
Refer to the pictures for the Wiring locations.
When you are done, you should have 3 wires going to the AV jack, and 2 going to the GPIO. You do not need to connect a wire to the ground on the AV jack, because we are getting the ground off the GPIO!
Step 4: 3D print!
I got a hold of a 3D pi case on Thingaverse, printed it, and drilled a hole in the bottom of the case for the ribbon cable to come out of.
I then made an enclosure for the portable raspberry pi on Autodesk 123D Design, which is a free software.
The enclosure holds the wires and screen in place, while the pi in its case can slide in and out of the enclosure for access to the GPIO/SD Card.
Step 5: Hot Glue, Hot Glue, Hot Glue!
This may seem like overkill, but use plenty of hot glue to reinforce the build. Hot glue is your best friend.
I got glued the LCD in place, making sure the Red, Black, and White wires come out of the notch in the enclosure.
I also ran some superglue around the perimeter of the LCD casing.
Step 6: Wire It Up!
Refer to the picture-diagram for the connections.
Before you solder any connections, please remember to slide on a piece of heat-shrink tubing before soldering!
First, I used my soldering iron to bore a hole in the enclosure for the 3.5mm Headphone jack.
Next, I soldered the Left and Right Audio Channels to the Ribbon Cable. This is the Red and White colored wires.
I then joined the Video (the White LCD wire, the yellow will also work, but the screen takes priority to the white wire) and +5v lines to the ribbon cable.
Finally, I soldered on a piece of wire to the ground terminal of the headphone jack and joined the 3 black wires together.
After soldering, I would recommend testing the pi, just to ensure everything is working alright. If so, hot glue your headphone jack in place. I used a LOT of hot glue, (probably too much) to mount the jack.
Use a flat-head screwdriver to push the wires into the enclosure.
Step 7: Glue on Bezel
This is the Final step for this project.
Start by laying everything in place (the pi) and lay down the Front plate. Hot glue the bottom-right in place and press down. Repeat this for the perimeter of the enclosure.
If you printed with ABS, you can paint on some acetone to smooth out the surface and fuse the surface together, creating a stronger and smoother job.
Step 8: You Are Done!
Congratulations! You have completed the Portable Raspberry Pi v4!
All you need to do now is plug it up (if you want to use a battery, I suggest you Attach it to the case with Velcro) and go!
Source: Portable Raspberry Pi (V4)