A few years ago I, almost literally, grabbed a POS (Point of Sale) pole-display out of a box of equipment which was on its way to the dumpster. I have a tiny bit of history with POS systems and thought it’d be cute to own one, without even knowing whether it worked or not.

I plugged it into a USB socket and it lit up, and I was able to echo something to it, so I determined it was “worth keeping”™ and stored it safely.

I stumbled over the display on the weekend during a bit of a cleaning up and decided it’d be a practical addition to the bunch of toys I’m assembling for the openHAB workshop I’m preparing. As I’m using an OpenBSD latptop with all the things I need I plugged it into that.

To cut a long story short, I couldn’t get it to work, but wasn’t quite sure what the reason was; my suspicion was that the required device wasn’t being created in the OS.

I asked, and as that link shows, within 24 hours I had an operating system kernel patch which added the necessary bits to make the “LD220-HP” work on OpenBSD.

$ dmesg | tail -2
uplcom0 at uhub3 port 2 configuration 1 interface 0 "Prolific Technology Inc. USB-Serial Controller" rev 1.10/3.10 addr 4
ucom3 at uplcom0

Ten minutes later, the small C program which opens the cuaU3 device, subscribes to MQTT and prints messages on a particular topic onto the display was assembled and running.

And the best part? The diff has been checked in, so it’ll be in the next version of OpenBSD.

Open Source: amazing!