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So, now for some solid requirements about my solar-powered Raspberry Pi project. To recap, the idea is to have a Pi hosting a small, static website, while powered by just a solar panel with minimal storage. Enough storage to keep it running if a cloud passes over, and to allow the Pi to gracefully boot up and shut down. This Pi would also act as a 'regular' Linux server, that you could SSH into and do stuff on. In other words, not just an appliance with a read-only file system.

Super capacitors make sense here. One of the goals is to avoid using a battery, and a capacitor should have a long lifespan. The current plan is to charge a cap bank with a solar panel, and have that feed the Pi via a linear regulator. Wasteful, but at the same time simple.

I spent some time looking into the Pi's GPIO, in terms of booting up and shutting down. The idea would be something like this:

• Sun comes up, panel begins charging cap bank.
• Cap bank hits Vmin, which turns on enable pin on linear regulator.
• Cap bank hits designated high voltage, Vmax, somewhere between the panel's max power voltage (Vmp) and open circuit voltage (Voc). This boots the Pi via GPIO.
• The panel presumably puts out more current than the Pi consumes, so this stays running for a while.
• The voltage begins to drop due to overcast conditions or, you know, nighttime.
  
• The cap hits the shutdown voltage (Vsht_dn), which signals the Pi to shut down. This also starts a 1 minute timer.
  • The voltage begins to rise again, because the cloud blew over.
    • After the timer expires, the Pi can be booted again via GPIO, if it hits Vmax.
  • The voltage continues to fall, because it's night.
    
    • The cap is sized so that there's a delay of about 1 minute before the Pi drains it to Vmin, at which point the linear regulator is disabled. This keeps low voltage from damaging the Pi.

This is fairly straightforward, just required some thinking on edge cases. And, some logic stuff I'll have to sort out, but that shouldn't be too bad.

So I'm realizing that I kind of like using this as a blogging platform. I want to develop my web site a little, and have a Wordpress blog I use there, but have been thinking about switching to something static-based. And/or using this more. A lot of it is that I need to think about what I really want it to be, and sit down and actually work on it.

I'm kind of thinking that this is a nice place for stream-of-consciousness, generally updates about life. It's a natural extension from posting about stuff on the Fediverse, but still accessible for those not on it. Really, the comments are one of the things that I kind of wonder if I'd miss from giving up Wordpress. It was nice to get one once in a while, but there was also a lot of spam. Plus, email is a thing. In the old days of the web, people set up small personal sites, and maybe publish emails they received there. That could be automated a little, but something like that?

Some sort of scheme to accept comment via email and publish them as updates to static site? Might be interesting.

In the mean time, I just stick a Fedi account as part of the signature here, and get pinged when this actually federates. And I suppose then I could have discussions on Fedi as well, which is kind of slick.

Projects

With US politics being what they are, I find myself a little stressed out. I'm hoping that I can actually devote a little attention to making some progress on things. I do, in tiny, granular amounts now and then. But some of these I've been thinking of for years. Here is a selection:

• Power inverter/battery charger
• Solar MPPT charge controller
• DC-DC converter for microgrid type application, sharing power between DC buses
• Solar Pi, a Raspberry Pi web server powered by a solar panel, such that it's running only when the sun is shining

Really, the inverter is the thing I'd most like to get going. I more or less know how it should work, but as I envision it it will require learning a new microcontroller architecture, and designing a few boards. It will be a bit of an odyssey, but should actually be useful.

The Solar Pi is sort of a concept art project I came up with, and I may put that just beneath the inverter in terms of priority.

Animals

I may be adding a dog to my household. It will certainly be the source of plenty of pictures, as well as of preemption to the above projects, if it works out. Stay tuned.

Distractions

I just try to stay busy. It's easy to get caught in a doom loop. I hope everyone reading this has various ways they can escape the grind now and then. Take care of yourselves.

The 2024 holiday season is about to come to a close, or has already depending on how you look at it. I traveled and stayed with family, and will be returning home soon. It's been a good break from work, a change of scenery, and an opportunity to see new people.

It's also kind of tiring. Yes and no – I get to sleep in, but also have had a few late nights this time around. This is something I'd like to avoid going forward. I also brought projects with me, thinking I'd make progress on them with all that free time I'll have. Well, sort of. I have made progress on some things, but have completely ignored others. That's usually how it goes. I didn't spend enough time before I left on the mental calculation of what I'd actually be likely to look at; had I done so, it may have taken some of the pressure off.

Still, I'm happy I made it out. It's a little adventure. And, we had snow for Christmas! Years ago that wouldn't have been as much of a surprise, but it kind of has been more and more lately.

I have a longish drive to go here/return, but nothing I'm not used to. A few hours. Friends of mine have longer commutes on the order of 1-2 days, and so only make it to our hometown for major holidays.

January is still a little bit of a break. Work shouldn't be too bad, and some other things I'm involve in ramp down a little. It will likely be cold, despite misgivings about climate change and Christmas time, but also cozy in a way. Plus the days get longer.

Projects

Let's see, I'm posting here, which comes with some strife about whether I should make this my primary blog or not. It's a lot simpler than Wordpress, and mentally has a lower barrier, so there's that. A static site generator, however, is somewhere on the list, but we'll see.

The Solar Pi is something I'd like to get running this year. It's just a Raspberry Pi running a simple website, powered (mostly) when the sun is out. There's a good bit to explore there, but it's kind of a concept art project.

Microgrids – specifically DC ones – are something else. Basically, power converters that can share power bidirectionally, between different semi-independent systems. Like, an off-grid PV system that dumps some excess power into running network gear. Yes, grid-tied PV handily solves this, but this should be more fun.

The inverter – something I've had in my head for a decade – is another. That should be fun.

Animals

I thought I might be ending up with a dog, but things didn't work out as I'd imagined. Maybe this year.

In the mean time I enjoy the antics of George, and his feline relatives (through adoption) when he comes with me to visit my parents. The journey is tough for him, but he's happy being with the other cats which is nice.

The nature center I volunteer with is taking a break for the season, but that's always fun.

And That's It

That's all I have right now.

I'd like to attempt writing a Fediverse bot. I have a GoToSocial instance which works fairly well, even if it's still alpha software, and managed to create a bot account and post using a curl command.

I was thinking of using it for posting statuses from my hobbyist off-grid system. Basically, voltage, current, power, and/or energy readings taken off of the charge controller. I already have some scripts in place to do this, so I can read various things over SSH from across my LAN, so it's not that huge of a stretch.

Perhaps it would post once a day, or every hour. I'd probably be the main one to follow it, but it would fun to leave it open for others to as well. One would have to be careful of giving away too much information, but maybe something like daily production would suffice.

I think there's a good bit of potential with bots like this, especially ones you could interact with. That combined with GoToSocial, which has made running a small instance fairly easy (although not entirely trivial) opens a lot of possibilities.

I treat this as sort of like Fediverse microblogging, but slightly bigger. I just wanted to play around with the software, and I like it. But I'm not sure about giving up Wordpress. I mean, I kind of planned on doing that anyways, in favor of a static site of some sort, which I haven't done yet. And yes, I know Wordpress can interact with the Fediverse now.

Every time I think about what I'd like to do with my web presence, I face decision paralysis, enabled by wondering what exactly I would like to write about. So I end up putting it off, but I'm not sure that's a bad thing. I sit on a few domains, and post here and there, and maybe that's enough.

Now I think I'm going to go eat lunch.