Last week, lightning struck at Tidmarsh, the former cranberry bog where I’m conducting experiments for my Ph.D. research on sensor networks. We’ve had some nearby lightning strikes before that have caused some minor equipment damage (it’s one of the perils of working in this environment) but nothing quite so major as this. We have some protection against lightning—perhaps not as much as we should have, but it can be quite challenging when we have many cables extending out over a large area.

I was actually there on site when it happened, making myself a cup of tea in the guesthouse. I was looking the wrong way to see the actual bolt, but saw a flash and heard the thunder instantaneously, so that must have been it.

We lost pretty much the entire audio installation at the former impoundment. Closer examination of the damaged equipment tells the story of the path the current took.

I don’t think anything was hit directly, or the damage would have been even more extensive. Most likely, the lightning hit the ground very close to where one of our cameras is out in the marsh. That traveled about 150 meters through a CAT6 ethernet line, into port 4 on the switch in the south box:

carbonization on ethernet switch circuit board

For one of my home desktop setups, I have very particular keyboard requirements. Since I put the keyboard in my lap (there’s no desk/table, the monitor is suspended on a cantilevered arm) the pointing device needs to be integrated into the keyboard itself. I’ve become less of a fan of trackpads over the years, especially the terrible ones that are integrated into cheap wireless keyboard combos like the ubiquitous Logitech K400. Furthermore, as it’s a Linux machine and I’m very accustomed to the X11 clipboard, which uses the middle mouse button to paste, I want a physical middle button. I’ve only found one wireless keyboard that meets those requirements, and it’s Lenovo’s bluetooth keyboard with a TrackPoint:

The Lenovo TrackPoint wireless keyboard

I like the keyboards and TrackPoints on my ThinkPads, so it’s nice to have the same setup. Unfortunately, the wireless keyboard is a bit of a regression from the ones on my ThinkPads: it lacks the row above the function keys, the function keys have tiny markings with big icons for their secondary functions (which I don’t care about) and the build quality is overall not as good as older ThinkPads. I also don’t like Bluetooth (pairing is complicated, and it doesn’t work in the bootloader/BIOS). But, it works. Well, it did, at least until my TrackPoint stopped working one day. The keyboard continued to work, but the TrackPoint started drifting incessantly to the upper left no matter how it was deflected, followed by ceasing to work altogether (including the buttons) a couple of days later.

Background and Motivation

Since this project involves a bunch of digital audio stuff that some of my readers might not be familiar with, I’ll start by describing my motivation for the project and some of the background information about the protocols and hardware involved. If you’re already familiar with this stuff and just want to see the hack, jump to the next section.

I have a somewhat unusual audio setup at home. I use a DAW (digital audio workstation) software on my desktop computer as a digital mixer for all of the sound coming from it. Using JACK on Linux, I route the output of each program to a different mixer channel, so in addition to having different volume settings for each program, I can apply effects as well (such as equalization or applying a little bit of compression when watching a movie late at night, so the loud parts aren’t quite so loud.) I can then route the audio between multiple outputs, primarily my studio monitors and my headphone amplifier.

The sound card I use is an RME Digi9652. These are older PCI cards, which are now inexpensively available second-hand since newer computers have mostly PCI-e slots instead. But, the card still works on my motherboard, has great Linux support, and provides 26 inputs and 26 outputs with very low latency. Like many multichannel audio cards, all of the I/O is digital. The 9652 has three pairs of ADAT Lightpipe ports and one pair of coaxial S/PDIF connectors. In order to get analog audio in and out, it requires the use of external converters connected to the ADAT ports.

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