In the following Instructable I would like to present an easy to build and inexpensive frame for the Raspberry Pi and the official Raspberry Pi touch screen. It could be used as a RPi workstation, for a media center or as control center for your IoT projects.
When I received my first Raspberry Pi touchscreen, I got the impression that the device is a bit fragile and needs a supporting frame. In addition, I found the suggested solution to piggyback the Pi directly to the back of the screen suboptimal and to bulky. But I wanted to attach both touch screen and Pi onto one plate, to get a tablet-like construct whichcan rest on a desktop by itself and might be used as a interactive display and work station.
I desided to use an IKEA "Isberget" tablet holder plate (25 x 25 x 9 cm, about 3€/$) as the backbone for the workstation. "Isberget" basically is a 3 mm HIPS (high impact polystyrene) plate shaped as a L.The touch screen was placed centered at the long arm of the L.
A case for the Pi can be placed at two positions: either at the outer or at the inner side of the short arm of the L.
Both solutions are working and are presented below.
- Placing the Pi case on the outside allows good access to USB, HDMI ports and the GPIO, but a longer USB (power) cable to connect Pi and touch screen is required.This version is presented at "Step 1"
- Placing the PI on the inner side inside may look better, e.g. for a media center, but restricts access to HDMI and other ports. This version is presented at "Step 2"
Step 1: Version One - the Pi on the Outside
- IKEA "isberget" tablet stand (get it from your next IKEA. I got four IKEAs around here)
- Raspberry Pi with case. I assume that most commercially available cases could be used.
- an official Raspberry Pi touch screen.
- 2 to 3A/5V USB charger with micro USB plug.
- a USB/micro USB cable to power the Pi via the touch screen. Use a good, thick cable, as underdimensionized ones may not work well (Rainbow square). You just need a "power cable" version, as no data lines are required.
- a 30 cm long "Pi camera cable" to connect the video in port of the touch screen with the video connector of the Pi.
- 4 or 5 mm rectangular rods, Preferentally from acrylic or polystyrene/ABS, as these materials can be glued well to the material of tablet stand.
- 2 x 8 or 3 x 10 mm aluminum rods (or similar).
- a piece of 2 or 3 mm thick plastic, about 6 x 7 cm large.
- four M2.5 screws.
- four 10 mm M3 screws with nuts.
- optional: a small breadboard with cables, in case a cobbler.
As a first step I marked a rectangular area of 16.7 x 10.2 cm at the center of the larger side of the "Isberget", then I cut at the lines and cleaned the edges. As the HIPS plastic sheet now had lost some stability, it was necessary to stablize it with some kind of beams. In the initial version I used a L-shaped aluminum profiles glued to the plastic (see next step). But using 5 mm acrylic beams, I used left overs from a laser cut acrylic plate, around the cutout gave a much higher stability. In addition, this allowed to fix the touch screen in the cutout by two beams of a 2 x 10 mm aluminum strip, that were fixed with M3 screws at the screw threads on the touch screen housing. They hold the screen in place, but also help to organize the cables a bit.
To protect the electronics of the touch screen controller, a 5.8 x 6.6 cm plastic plate was attached to the touch screen with the provided spacer elements and M2.5 screws.
But before you attach the touch screen you have to cut a slot for the touch screen connection cable and one or two holes for the plug of the USB connection cable at the back of the frame. And, if you like to fix it with screws, do not forget to drill the holes for the mounting of the Pi case.
Now fix the Pi case to the modified "Isberget" and place your Pi into it. Then place the touch screen in the cutout, please watch for the correct orientation, and fix it with the two aluminum beams. Now attach the touch screen connection and the USB power cables to Pi and touch screen.
I finally added a small bread board to the backside of the workstation, to make it easier to connect the Pi with some sensors, devices or an Arduino nano/Trinket. Alternatively you may add here a speaker or another device.
To be able to use the system without an external keyboard, you may want to install a virtual keyboard as "Florence".
Details on this can be found elsewere, and there is an easy fix for the Rapian Jessi/Florence problem.
Step 2: Version Two: the Pi Inside
An alternative option is to place the Pi on the inside of the frame. I tried this using the Pimoroni Pibow coupé case.
This comes closer to a tablet type solution and looks cleaner, but you will have quite limited access to the HDMI and audio port. In addition you will need a special USB cable with an angular plug to power the Pi (e.g. http://www.amazon.com/StarTech-com-Micro-USB-Cabl... Make sure you order the correct direction!).
While it construct is working well, I prefered the other solution.