2026-06-10 21:00:00
A couple years ago I put together a Secular Solstice Songbook, a compilation of all the songs we've sung at Boston Solstice. Anna Tchetchetkine and I led a session of group singing at LessOnline, following up from an informal one the year before, and I noticed several annoying things with its chord handling:
Despite being digital, it didn't support transposition.
Some songs didn't repeat the chord if they were unchanged, which meant that when scrolling new lyrics into view you'd lose the chords.
This is minor, but I like to align the chords in a grid and the repeat sign was very slightly to narrow, throwing off the grid.
In asked Claude Code to fix these, and it did almost all of it. The exception was a few cases where it wasn't obvious which chords to use and I needed to make some manual edits.
My favorite part is that it preserves the grid even when the addition of accidentals changes widths. For example, here are the chords I have for haMephorash:
C Am C Am F G C G C FG Am F G E Am /
If for some reason I wanted to play it in E instead of
C, I could bring it up four semitones:
E C#m E C#m A B E B E AB C#m A B Ab C#m /
Note that because C#m is wider the columns containing it
are now slightly wider to make room, accross the board.
I'm pretty happy with it, though I haven't tried using it for real yet.
2026-06-09 21:00:00
DIY testing of air cleaning is practical, and thoughtful experimental design can substitute for high-quality sensors including for evaluating air purifier setups that give >100,000x particle reductions.
I've done a lot of DIY testing over the years ( 1, 2, 3, 4, 5, 6). The goal is generally to understand how well something removes particles from the air. A professional particle counter (example) costs thousands of dollars, and they're amazing devices, but what you're paying for is convenience, reliability, calibration, and dynamic range. If we're willing to give up on convenience and buy multiple devices for reliability, we can cheaply address calibration and dynamic range with experimental design.
The cheapest ready-to-go option for DIY work today is probably the Temtop P600 which I see as $70. While I haven't tried it, it's a stripped-down version of the Temptop M2000 which I bought several years ago to use for my DIY experiments. If you want to make something cheaper, you can get a PMS5003, which I see as $21, and connect it to a cheap SoC (~$10) or to an Android phone (adapters in the $15 range). At scale I think you could get this down below $15: a PMS5003 or clone at high volume would be ~$7, the phone adapter would be under $1 at this scale, software <$1, then a box, assembly, and some QC.
The Temtop and PMS5003 are somewhat calibrated, but fortunately we don't need to know absolute particle counts. We just need some number that is, within a reasonable range, linearly proportional to particle counts. As long as the meter is stable over time we can look at ratios. For example, if you're trying to see how quickly something can clear smoke from a room you don't need to generate a target amount of smoke or know exactly how much smoke you've generated: you can just measure the half life. This gives you relative efficacy directly or CADR if you have a sealed room of known volume.
Dynamic range is harder, but still doesn't require professional sensors. Let's say you want to measure the efficacy of a DIY cleanroom setup. (Note: if you're excited about this Coefficient Giving might be willing to fund you). You have some kind of outer room where you'll fill the air with particles, and some kind of inner area where you want to ensure you're keeping particle counts down. The sensors I've talked about above can measure particle concentrations over a ~500-1,000x range, but if you're trying to assess whether you've successfully achieved a larger reduction a simple experiment won't have the range. A level of particles you can measure outside will give "below range" inside, and a level you can measure inside will give "above range" outside. What can you do?
The simplest option is just to wait longer. This is really not bad! Particle counters are really very good at only reporting a particle when there is one, which means you can get 10x the sensitivity by running for 10x as long. Still, if we have 1000x range and want to measure a 100,000x reduction those are some long waits. We can speed it up (or extend our range further) by bringing air concentration into the range of our sensors.
The next simplest option would be to have one sensor inside and one outside, along with an air purifier outside. Calibrate the sensors to each other ahead of time and then start off the experiment with a very high concentration (above range outside, within range inside). Let your air purifier bring levels down outside. After passing through a middle region (above range outside, below range inside) you get within range outside (but below range inside). Here's an example of what an idealized version of this experiment might look like:
There's no time during which we have both the internal and external measurement, but we can extrapolate our curves and estimate that when the inside sensor is reading 10 the outside sensor would read 1,000,000.
Instead of relying on the air purifier to remove a consistent 10% of particles from the outside each minute, however, we can add a third sensor. A MERV-16 fan removes at least 95% of the particles, so we can make a box with a fan and a MERV-16 filter and measure counts inside that box. The box should not be sealed; positive pressure from the fan is enough to ensure we're only measuring the post-MERV concentration:
Unfortunately this is still not enough to connect our Inside and Outside curves, but we can add a fourth and final link in the chain with a HEPA filter to remove at least 99.97% of particles:
Now we have substantial temporal overlap between each pair of sensors and can plot their ratios:
The parts of this plot we care about are the horizontal sections: that's where the values reported by each sensor are moving proportionally. Sloped (and ratio=1) sections aren't meaningful, since they're cases where a sensor is out of range.
We can then read off a 20x reduction for the MERV-16, a 167x reduction from the MERV to the HEPA, and a 30x reduction from HEPA to inside the cleanroom. These stack to give the expected 100,000x reduction end to end.
Of course real data would be much messier, but the basic idea should be solid.
Additional logistical notes:
The particle levels we're talking about here are really high, and you don't want to be breathing them. Ideally you can set it up so you run the whole experiment from outside a sealed room, monitoring levels remotely. If you do need to go inside, use a well-fitting P100 (and keep in mind that they don't work with beards).
I've used smoke, but smoke is sticky and poorly behaved. Better to use aerosolized salt. You can get it in the air with an ultrasonic humidifier and salt water, and as long as the relative humidity is below 45% the droplets will dry out to pure salt crystals. If you're doing this in a humid place you could use a dehumidifier.
Even levels much lower than this will set off your smoke alarm, and levels this high might break it. I'd remove it, or at least turn it off and seal it well with plastic.
Apparently the salt gets everywhere and is mildly corrosive (like living by the beach for a long time). Take everything out of the room, and either encase the room in disposable plastic sheeting (thin painter's sheeting is very cheap) or wipe down all surfaces with a wet cloth after.
2026-06-07 21:00:00
I was in SF this weekend for LessOnline. It's nominally a blogging conference, but in practice it's more of a Rationalist meetup. I was there in my personal capacity, though I did end up having a lot of conversations about biosecurity and may have accidentally done some fundraising. Lots of good parts, but my favorite was calling and playing for a contra dance:
This was similar to the house party dances I've called a few times. Two sets, which was very tight (cozy!) but it was a good time!
We had a live band: Ben on piano, Aleks and me on fiddle, Catherine on sax, and a volunteer on cajon. I called while playing, which works as long as we stick to simple tunes. We had no sound reinforcement, and I did need to do some shouting when calling, but the low friction and "each musician adds something" feel of an all-acoustic dance is pretty great. It was short enough (55min), and each dance needed few enough calls, that my voice feels fine.
Almost all longways whole set dances:
I didn't introduce anything that required roles, kept the piece count low, and reused figures a lot. I'd like a few more dances in this general structure: I recently added Luke's Charge and Drag, which is just the right amount of additional variation.
Unlike a house party dance we didn't take any breaks: there were enough people that we could dance straight through. I did give people a lot of time to rest and chat before teaching each dance, though, since otherwise I expect we'd have had a lot of attrition.
One thing I like about doing such simple dances is that, even with a crowd where a large majority have never danced before, there's no need to call the whole way through. People also really quickly get a sense of starting each figure when the music says to, which I think takes much longer to develop if the dance is challenging.
We put it together last minute, but it was a big success and I'm glad we did it!
2026-06-06 21:00:00
Five years ago I read a post on the EA Forum arguing that "election campaign contributions might be a way in which you can have a substantial impact as a small donor". It struck me as weird but plausible: a combination that you see a lot of on the Forum.
A few months later I read another post, a case for Carrick Flynn in particular. It made a lot of sense, but while I don't remember my specific reservations I do remember not being convinced initially. After a lot of talking with Julia and others, however, this campaign did seem like a really promising opportunity. Six days later we made the donation:
We hadn't donated to a political campaign since college, but Julia was impressed with this candidate's work on pandemic preparedness, which is an area we've both thought was important for a long time. In general, we prefer to donate through funds because they are able to put a lot more time and attention into identifying excellent donation opportunities, but campaign finance rules mean this model doesn't work for political donations.
Flynn lost, and not for lack of funding. People took away a range of lessons (see the comments too!) from the attempt; personally my largest was that it's really important to assess early on whether the candidate is resonating with voters, and proxies like "previously elected to local office here" are super valuable.
The argument for individuals donating to support candidates still made sense to me, and I would still have been willing to do it for the right opportunity. For the next few years, however, I didn't come across any that were sufficiently compelling. And with a lot of other things going on in my life I didn't seek these out.
In Fall 2025 friends started discussing political donations more, and I met Eric Neyman who was putting together a working group to identify and rank political donation opportunities from the perspective of "making the long-term future go well." I read his analysis of cost-effectiveness of donating to Alex Bores' campaign, talked to friends, and talked with Bores himself briefly when I was in NYC for EAG. Not wanting to repeat earlier mistakes, I was glad to see he's already been evaluated by the electorate in becoming a state legislator. Which is not to say he'll definitely win: it's a competitive field and he's at 42% on Manifold. Still, I decided to donate, and later donated to several other people that some combination of Neyman's group, the Secure AI Project, and politics-focused EAs recommended. They've mostly been Democrats so far, but party isn't my goal: it's about what I expect the candidates will do if elected.
After continuing to think about this, I actually think I should make political donations my primary method of giving. The vast majority of charitable dollars legally can't go to candidates, and I don't expect this to change. Donors with a lot of money to distribute have the same lowish hard-dollar limits I have, and much of the remainder, including a lot of likely-forthcoming Anthropic employee funding, is in donor advised funds. This means my money is unusually well-suited to help fill what I see as one of the highest priority gaps.
This is not the full case (see Ozy, Lincoln, and Scott) but it's the part that took longest to click for me.
Overall I feel pretty mixed about this. On the one hand, for years I've wanted to apply my comparative advantage as an independent individual to make more impactful donations, and it's great to finally really be doing this. On the other, it's kind of depressing. It's a familiar feeling: when I moved from primarily funding global poverty to trying to reduce catastrophic risk I felt the same way: more distance from helping the world's poorest people in the present, when they would very clearly benefit a lot from my money. But I do think it's here my money will do the most good, and that's what drives me.
Comment via: facebook, lesswrong, the EA Forum, mastodon, bluesky, substack
2026-06-05 21:00:00
I'm leading a non-profit team building a pathogen-agnostic early-warning system. As AI systems become increasingly capable substitutes for expert human biologist expertise, the risk that someone could engineer a pathogen to spread widely before detection is going up. We've made great progress and we're now running the world's largest metagenomic biosurveillance network, but there's still a huge amount that needs doing: we're hiring!
We're processing >50B read pairs of wastewater and nasal swab data each week (more than anyone else!) and will be more than doubling this in the next year. At the same time, we need to bring our end to end time down from ~12hr to ~2hr (massively parallel problem, should be possible to get <1hr).
This means we're looking for people who know how to build and scale processing systems and infra, and don't need a bio background:
Software Engineer, High-Performance Pipelines: Engineering our metagenomic detection pipelines for speed, scalability, and reliability. (job description, ~L4-L5 equiv at Google, $165-190k)
Senior Cloud Infrastructure Engineer: Own our AWS infra, which enables everything above (job description, ~L5-L6 equiv at Google, $195-220k)
For both of these we're looking for people to work with us in-person in Kendall Sq (Cambridge MA).
We're offering a $5,000 referral bonus, paid out in stages: $150 if we invite them to a technical interview, another $650 if we bring them on site, another $2000 if they accept an offer from us, and a final $2,200 at the three month mark. If you know engineers, a few minutes thinking about who might be a good fit is worth your time, and theirs!
Comment via: facebook, lesswrong, the EA Forum, mastodon, bluesky, substack
2026-06-03 21:00:00
Running an air purifier on a battery could be really useful in an emergency that combined a biological or nuclear threat with a power outage. Getting one that can run on 12V DC and attaching it to a LiFePO4 battery is about $188 (plus $164 for the purifier) for something that will give you 141 CFM for over a week.
I've been thinking about DIY biohardening, primarily to reduce risks from environment-to-human threats, and a lot of what's out there assumes the power grid stays up. This doesn't seem like a good assumption: even if society does a fantastic job protecting essential workers and prioritizing keeping the grid up, I expect many more outages than we have today, and longer ones. If an outage means you lose positive pressure and get sick, that's really very bad!
If I needed to build a DIY cleanroom today, I'd start with my AirFanta 3Pro. While it being HEPA is overkill for cleaning the air that's already in a space, it's great if your goal is to clean air as it enters a space.
The simplest option is to buy a portable power supply. I have the 1,056 Wh Anker SOLIX c1000 and at $450 on Amazon it's comes to $0.43 / Wh. If I trust AliExpress, I could maybe get it for $322 ($0.31 / Wh). These look to be pretty typical for portable power supplies, and I like that the SOLIX supports solar charging.
Another option would be deep cycle AGM lead-acid batteries. This is what I went with in 2018. Doing some reading now, though, it seems like they're rarely worth it anymore. A 100Ah AGM, which you should really only take 50 Ah of, is $160, and a 100Ah LiFePO4, which can be discharged down to 80-100%, is $147. Plus the LiFePO4 is less than half the weight: 24lb vs 57lb.
Unlike the portable power supply, version, this requires assembling a few components:
A coulomb counter shunt, which tells you how much power you've drawn so you know how much is available and whether you're almost out. ($16.19)
A fuse holder and fuses, so a short circuit doesn't start a fire or destroy your battery. ($1.70)
Connectors, so you can easily connect and disconnect without worrying about messing up polarity and destroying something. ($4.66)
Charger, so you can bring the battery back up to full when you have access to power again. ($18.99)
I already had all of this from my earlier inverter project, except for the fuse (integrated into the inverter) and connector to the AirFanta (which takes a 5.5mm x 2.5mm center-positive barrel jack). Hooking it all up, I can run my AirFanta off grid:
If I didn't already have most of this, I'd have been spending $188 for 1280 Wh, or $0.15 / Wh. This is much better than the portable power supply, it also provides much less: I can only use it to power things with 12V DC.
Now, you might imagine someone would sell a box that wraps a battery and provides these extras so you don't need to DIY anything, but as far as I can tell this doesn't quite exist. People sell "battery box power centers" for use on boats, but they don't measure how much power you've drawn. With a modern LiFePO4 battery this is a big issue, because you can't really estimate power from voltage. These boxes also don't provide charging: on a boat that's not a feature you're looking for. So I think full featured portable power supplies and DIY setups are the two main options.
Personally, I'm glad to have both systems:
The Anker SOLIX portable power supply is much more flexible: it powers things over AC, provides USB ports, charges very quickly from the wall if power is available, and can be recharged by solar.
The DIY 12v system is simpler, less likely to break, modular and easy to fix, and cheaper. If I want to go bigger, I can expand my total capacity just by buying additional batteries at $0.11 / Wh.
I can also move power between the two systems with relatively low losses, to take advantage of flexibility or capacity as needed.
I'd really like to know how much power this would draw and how long I could run it for, but without actually building something and taking measurements all I can do is estimate. A big question is whether it could get to useful levels of pressurization: I don't think it would get anywhere close to +75 Pa, but maybe +10 Pa would still be possible and good enough if we can avoid wind by pressurizing something inside an existing building? For now I'll set all that aside and look just at the case that's easy for me to work with: running the air purifier as it's designed to be operated.
So: how long can I run the AirFanta for? What setting should I use if I want to maximize my clean air delivery rate (CADR)?
The manufacturer gives power and throughput numbers, but I expect slightly lower power usage from running it directly on DC. They report 33.2W on the highest setting while I measured 29.2W, so this looks like a factor of 14%, just around where you'd expect. Scaling down by that factor, and calculating CFM per Watt, I get:
| Setting | Power (W) | CFM | CFM/W |
|---|---|---|---|
| 1 | 1.93 | 57 | 30 |
| 2 | 4.12 | 141 | 34 |
| 3 | 9.74 | 247 | 25 |
| 4 | 16.58 | 321 | 19 |
| 5 | 24.04 | 374 | 16 |
| 6 | 29.12 | 413 | 14 |
You can see that setting 2 is the most efficient but also produces less air: if you have unlimited purifiers you should run them all on 2, but if you need more output you might need to run them higher to get sufficient CADR.
We can also estimate the runtime we'd get at different speeds. I'll model the 12v DIY system as a 100Ah LiFePO4 12.8v cell (1,280 Wh) while the Anker C1000 is 1,056 Wh. [1] I'm estimating that the C1000 loses 2.5W just by being on, an additional 7W if it needs to run the inverter, loses 7% on DC-DC conversion (12V port) and 14% on DC-AC conversion (AC outlets). So I'll model the 12V DIY system, the C1000 via the 12V port, and the C1000 via the AC ports (where we then lose another 14% on AC-DC conversion):
| Setting | 12 DIY | C1000 DC | C1000 AC |
|---|---|---|---|
| 1 | 663 | 231 | 87 |
| 2 | 310 | 152 | 70 |
| 3 | 131 | 81 | 47 |
| 4 | 77 | 52 | 33 |
| 5 | 53 | 37 | 25 |
| 6 | 44 | 31 | 22 |
The effect of overhead on runtime is substantial, especially at low draw. On setting #2, producing 141 CFM, the DIY system should be able to run for just under thirteen days, the C1000 with DC for just over six, and the C1000 with AC for a little less than three. At higher draw this is less of a concern, since if the fan needs 29W losing 2.5W (or even 9.5W) to overhead matters less.
This pushes the analysis much more in the direction of the DIY system, especially if lower current is enough.
[1] Because the LiFePO4 cell has charge limiting circuitry built in,
it's ok to run it to 0%: it will just shut off. While you shouldn't
store it fully discharged, in this case I'm imagining we recharge it
promptly. This means we get the full capacity from both batteries.