A variation of the pattern from yesterday; say you have:

if (x == 3) {
    y = 0;
} else {
    y = 1;
}

When these are zero and one, sometimes this will give a better match, since booleans are evaluated as such:

y = (x != 3);

It's rare to have something else than zero or one work for this pattern (e.g. you would rarely write y = (x != 3) * 2 + 1).

For over ten years, the only way I have had of knowing what our solar panels are doing has been an impulse monitor on the generation meter, counting the flashes of its LED. It has always been a bit flaky due to battery changes or loose connections, and there has never been a way to see solar generation alongside the energy used by the rest of the house. This week I have fixed that, by building a small ESPHome sensor which talks directly to the inverter. I am still reeling slightly: with AI assistance, it took under a week from idea to working implementation, and it is a project I would certainly never have attempted otherwise. The result is zeversolar-esphome.

The inverter is a Zeversolar Zeverlution 3680, which has an RS485 port but no Wi-Fi or Ethernet module. It doesn’t speak Modbus; it uses Eversolar’s own master/slave protocol, which nobody has officially documented but which several people have reverse-engineered over the years (credit to eversolar-monitor, Heliograph and others). Manufacturer support for Eversolar/Zeversolar inverters apparently ended in December 2019 when the company went out of business.

The rating plate on my inverter.

A while ago I had looked into what ports were available on this inverter with a view to connecting some sort of monitoring, but I had abandoned it as “too hard”. While working on some Home Assistant configuration, Claude suggested the idea again, but similarly wrote it off initially. I encouraged it to explore a bit further, and supplied the model number of the inverter, at which point the picture got a lot more promising. After a bit of back-and-forth about hardware, we settled on an M5Stack Atom Lite on an Atomic RS485 Base. The main attraction was that it already comes in a case, so I didn’t need to design (or, more likely, bodge) an enclosure.

While I waited for the parts to arrive, Claude wrote the firmware: an ESPHome external component built around a small, dependency-free C++ driver, with host-side unit tests against byte captures that other people had published from other models. I found it slightly surreal to have a tested protocol driver before owning any hardware to run it on.

Cables

The parts came before the tools I needed to get into the inverter safely (a DC clamp meter and a T25 screwdriver bit), so in the meantime I made up an RS485 cable - this uses an RJ45 connection at one end, and some custom wiring at the other. My first attempt was with some CAT 6, but (as Claude had pointed out and I had ignored) its solid-core conductors are much harder to twist together. So I gave up and sacrificed an old CAT 5e patch lead instead, which went much better.

The custom end of the cable, before being taped up.

The risky bit

On a Zeverlution, the RJ45 sockets are inside the wiring compartment, which means taking the cover off to install the monitor. The manual addresses this part to qualified electricians. So the step I was most nervous about was not the software at all, but safely isolating the inverter.

Inside the inverter, with the cover off.

I did this with appropriate caution, following the instructions from the manual carefully, and also waiting until after dark just in case. Now that I understand how the DC clips from the panels work, I can see how to do this safely during daytime too – but hopefully this won’t be necessary.

Plugged in, and threaded through the cable gland.

Warning: if you’re not confident, I would always advise to get an electrician to do this bit. Do what I say, not what I do.

Debugging over Wi-Fi

Once the device was installed, the nice thing about ESPHome is that I never need to go back in the loft again to update it – it reflashes over Wi-Fi. I’ve taken full advantage of this for debugging, and for reading the wire protocol directly from the logs.

The finished device. Green means generating.

Separately, I’ve used Claude to integrate the new sensors into Home Assistant. Solar generation finally sits in the Energy dashboard next to the rest of the house’s usage, which was the whole point.

Reflections

This was a fun, quick project, and it solved a problem that has eluded me for a decade. I want to be honest about how much of that is down to the AI: I would not have attempted any of this on my own. I could not have told you the protocol existed, never mind implemented it. My contribution was everything involving a screwdriver, and ordering some hardware.

A brand new release 0.1.16 of the RcppSimdJson package is now on CRAN, has been built for r2u, and is updated on r-universe.

RcppSimdJson wraps the fantastic and genuinely impressive simdjson library by Daniel Lemire and collaborators. Via very clever algorithmic engineering to obtain largely branch-free code, coupled with modern C++ and newer compiler instructions, it results in parsing gigabytes of JSON parsed per second which is quite mindboggling. The best-case performance is ‘faster than CPU speed’ as use of parallel SIMD instructions and careful branch avoidance can lead to less than one cpu cycle per byte parsed; see the video of the talk by Daniel Lemire at QCon.

This version updates to the recent 5.0.2 upstream release with improved performance. Given the strong focus on performance, this release also alters some of the R and C++ interfaces to be more direct. Rcpp generally aims for a balance between readable / maintainable code and good performance; this moves the dial closer to strong performance gains. As Daniel noted in a table in the (main) PR for this release, this now consistently beats yyjsonr, and improves considerably over the previous release of this package. I had made some smaller interim upgrades earlier (without a CRAN releases), and made a number of minor standard packaging updates.

The short NEWS entry for this release follows.

Changes in version 0.1.16 (2026-10-09)

• simdjson was upgraded to versions 4.6.1 and 4.6.3 (Dirk in #100 and #102 fixing #99 and #101)

• simdjson was upgraded to version 5.0.2 (Daniel in #104)

• A number of small tweaks to the Rcpp interface were made too (Daniel in #104)

• Diagnostics for gcc and clang are not suppressed per CRAN Policy (Dirk in #106 closing #105)

• The continuous integration matrix was extended to g++ version 15 and 16 (Dirk in #108 closing #107)

• A few minor packaging nags were address (Dirk in #109)

Courtesy of my CRANberries, there is also a diffstat report for this release. For questions, suggestions, or issues please use the issue tracker at the GitHub repo.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. If you like this or other open-source work I do, you can now sponsor me at GitHub.

A few days ago, a colleague reached out to me, asking if I could help draft a resolution on digital autonomy and free software for the upcoming renewal of our collective bargaining agreement. Although she's very politicised and generally a great individual, she is not a techie and we never really talked about these issues before.

This took me by surprise. I should have been rejoicing; no, I should have been the one who brought up this topic in our union. Wasn't I the technical expert on these issues? But alas, my first reaction when she came to me was to snicker and tell myself: "That's cute, but nothing's ever gonna change, Big Tech is too strong and our governments don't give a damn."

How sad and cynical is that? That's not the person I want to be.

Something in the Quebecois political landscape has shifted in the last few years with regards to tech. More and more "regular" people seem to be talking about the importance of digital autonomy, how government services shouldn't rely on Big Tech and how we should be using FOSS on hardware we actually control.

A few years ago, I would have been at the vanguard of this change. I would have been part of the creation of Données souveraines Québec. Heck, they are organising a whole conference next week and I'm not even going. How did this happen to me?

I first fell for Free Software for its political ideals: Knowledge Should Be Free, Cooperation Is More Efficient Than Competition, Centralisation Should Be Avoided When Possible, etc. I still believe in all of this, but somehow, after years of fighting for change in the tech world, I have retreated into technical work. I maintain Debian packages as a hobby and to scratch my own itch. I run services for myself and a few friends. I organise Debian User Group meetings.

To be clear, I haven't generally given up. I'm very politically active in my union and at work, I'm a good member of my housing cooperative and I'm still fighting against the industrialisation of natural spaces in my neighborhood. But when it comes time to defend freedom in the tech world, lately, I've just been shrugging and accepting I should use Microsoft Teams like every one else does. I want this to change and to do so, I need to free some time.

Lintian

Two years ago, I added myself to Lintian's Uploaders list. Up until then¹, I enjoyed fixing little issues here and there and liked creating new tags to help out the Python Team, where most of my Debian time was spent.

Lintian was badly in need of a new maintainer and as I felt it was an important project, I decided to step in. 37 releases and about 160 closed bugs later², I'm done.

To be honest, I haven't had much fun maintaining Lintian lately. Bugs keep piling on the BTS, so much so I have mostly been ignoring them for the past few months. In fact, most of the actual work triaging, writing code and fixing bug has been done by Nilesh Patra for a while now.

All this to say, if you care about Lintian, you should consider adding yourself to the Uploaders list, as I'm out and Nilesh can't do all the work by himself.

He's a great person to work with and since I don't want to suddenly leave him all alone, I'll be sticking around for a few more weeks in the hope someone else will volunteer to help out. A smooth transition with a new co-maintainer would really be nice!

If you're interested, don't hesitate to reach out to me on IRC or by email.