Of course that meant booting the Raspberry Pi with no display attached at all because the Joy-IT display needs a special driver which I had not installed. I had, however, set up the Pi to try to find the wireless network on my phone's Personal Hotspot.
Multicast DNS to the rescue
So... I booted up what looked like a keyboard and then used Termius on my phone to connect to the name I'd previously set for the Pi: cyberdeck.local. .local DNS names are interesting because they aren't resolved by the standard DNS resolver method but through Multicast DNS using the Avahi daemon running on Debian on the Pi.
Oct 26 12:28:41 cyberdeck avahi-daemon[558]: Server startup complete. Host name is cyberdeck.local.
That allowed Termius to find the device on the shared Personal Hotspot network.
From there I was able to make the Pi download the relevant Joy-IT driver and start configuring. And I hit a roadblock. The instructions for configuring it are in a PDF. And the iPhone stubbornly allowed me to select but not copy the relevant lines to add to /boot/config.txt.
I really did not want to flip back and forth between nano running in Termius and this PDF, and was worried I'd bork config.txt and have an unbootable machine.
Modern problems require modern solutions
But then I remembered that the iPhone Photos app can OCR text! So, I took a screenshot of the PDF and
was able to select and copy the text from a photo of a PDF.
I pasted that into /boot/config.txt (and double-checked the OCR) and hand edited /boot/cmdline.txt to add the fbcon=map:10 to the console= line.
And it worked! A quick sudo reboot and I had a working CYBERDECK!
After I finally got home I realized that as nice as the little screen and connector are, they are very flimsy and I really needed something to stabilize them. So it was off to OpenSCAD to design a bracket that fits between the display and the Pi and gives it some stability.
Here's the thing in OpenSCAD.
And here's the printed item.
The triangular portion rests against the corner of the Pi; the two slots match two parts of the display PCB that stick out. It's possible to screw the thing to the display PCB as there are two holes in the PCB for that purpose.
If you need to build one of these, here's the code:
difference() {
linear_extrude(70)
polygon([[0,1.5], [0,20],
[8,20], [8,25], [11,25], [11,19],
[18,19], [14,12], [20, 9], [18,1.5],
[0,1.5]]);
for (z = [13, 51]) {
translate([8, 21, z])
rotate([0,90,0])
linear_extrude(3) square([11,2]);
}
}
And here's what it looks like in place.
Now I have a lightweight machine that I can travel with and either use with the small screen or connect to a TV via HDMI. It can tether to my phone or connect to local WiFi and has an Ethernet port (I discovered that in some hotels the Ethernet going to the TV actually has Internet connectivity). The Pi needs about 5W so I can power it from USB-C power supplies and even portable batteries.
So, now I'm ready for anything.
