Wiring the screen

The Waveshare 2,8 inch. screen for Raspberry Pi is designed to be plugged on top of the Raspberry Pi using the GPIO pins, but we're going to build an extension cable that goes from the Raspberry Pi on the Base to the screen inside the Monitor box body above.

There are 26 pins in the screen, in two rows of 13. Since we need that many cables, we're going to need really thin and flexible cables to avoid cluttering the case. If you use cables that are too thick or too rigid, the case won't close.

The best solution I found is to use a 26-lane IDC ribbon cable with connector

First of all, since the screen is designed to be plugged on top of the male GPIO pins on the Raspberry Pi, the manufacturer soldered a female socket on the back of the display to make it fit perfectly. Unfortunately, 26 pin IDC male-to-female ribbon cables are quite hard to find.

Luckily, the display manufacturer thought of that and placed 26 replicated connections to the side where you can solder the socket of your liking. We're going to solder there a Male IDC 26 pin socket, so we'll end up with the same connection, but male instead of female.

Before

After soldering the socket

Do not connect the Raspberry Pi to the screen yet, you might burn something!

Because the screen is designed to go on top of the Raspberry Pi, the manufacturer had to mirror the pins to make it match. If we were to connect the cable without modifying it, the connections would be as follows:

PIN 1 → PIN 2 ⚠️
PIN 2 → PIN 1 ⚠️
PIN 3 → PIN 4 ⚠️
PIN 4 → PIN 3 ⚠️
PIN 5 → PIN 6 ⚠️
PIN 6 → PIN 5 ⚠️
… same thing for the rest of the 26 pins

So, we're going to modify the cable to correct the mirroring. To do so, we need to switch every pair of cables, like so:

Cable 1 → Cable 2 ✅
Cable 2 → Cable 1 ✅
Cable 3 → Cable 4 ✅
Cable 4 → Cable 3 ✅
Cable 5 → Cable 6 ✅
Cable 6 → Cable 5 ✅
… same thing for the rest of the 26 pins

The resulting mirrored cable should look like this.

This is probably the most laborious task, it requires soldering 26 tiny cables, but it will be worth the effort! Be sure to protect the exposed cables with something like the Shrink tube. Once you're done, connect the screen to the Raspberry Pi using this cable as follows:

Check that PIN 1 on the Raspberry Pi is routed to the correct PIN 1 on the screen, take a look at the orientation of the cable on the image above.

You'll need to bend PINs 27 and 28 on the Raspberry Pi to let the IDC connector in. Do it carefully and protect them from shorting with pins 29 and 30.

Finally you're ready to connect the Raspberry Pi to the screen using this custom cable and turn it on. It should work!