Quick Thoughts on Our First Sampling Run

Cross-posted from my NAO Notebook

While the NAO has primarily focused on wastewater, we're now spinning up a swab sampling effort. The idea is to go to busy public places, ask people to swab their noses, pool the swabs, sequence them, and look for novel pathogens. We did our first collection run yesterday:

After months of planning and getting approvals, it was great to be out there! Some thoughts on how it went:

Scientific Notation Options

When working with numbers that span many orders of magnitude it's very helpful to use some form of scientific notation. At its core, scientific notation expresses a number by breaking it down into a decimal ≥1 and <10 (the "significand" or "mantissa") and an integer representing the order of magnitude (the "exponent"). Traditionally this is written as:

3 × 104

While this communicates the necessary information, it has two main downsides:

  • It uses three constant characters ("× 10") to separate the significand and exponent.

  • It uses superscript, which doesn't work with some typesetting systems and adds awkwardly large line spacing at the best of times. And is generally lost on cut-and-paste.

Instead, I'm a big fan of e-notation, commonly used in programming and on calculators. This looks like:


Contra Caller Gender III

When I looked at the genders of dance callers at large contra dance events several years ago there was an interesting pattern where events were more likely to book a man and a woman than you'd expect by chance. With more years worth of data to look at, I thought it was worth checking if this was still the case.

To see the effect most clearly, I looked at events with two binary callers. [1] Here's what I saw:

Embedded Whistle Synth

A few years ago I ported my whistle synth system from my laptop to a Raspberry Pi. This was a big improvement, but I still wasn't that happy:

  • To get good quality audio in and out I was using a 2i2 audio interface, which is expensive, bulky, and has a lot of buttons and knobs that can be bumped.

  • To use a single mic for both whistle and talkbox I was using a cheap passive A/B switcher. Which feels fragile, causes pops when phantom power is on, and is one more thing to plug in.

  • It's hard to get super low levels of latency with the Pi. It's probably possible to get more performance out of my existing hardware than I'm managing, but as it is I'm not happy with it.

  • The Pi's SD card gets corrupted every so often, so I carry around a bunch of spares.

  • The Pi takes a little while to boot, which makes "no sound" ambiguous between "because the SD card is corrupt or I've plugged something in wrong" and "because it's still starting".

After my Electronic Harp Non-Mandolin project I was feeling more at home with electronics, and decided to build an embedded version of my whistle synth.

Somerville Porchfest Thoughts

This Saturday was Porchfest in Somerville, an annual festival where musicians around the city play on their porches and people wander around listening. As in the past few years Cecilia and I (Kingfisher) played for contra dancing:

Custom Audio Switch Box

When I play live I have a bunch of instruments, including:

I also have some effects, primarily a talkbox and an audio-to-audio synth pedal. Normally I route the mandolin into the effects, but I've recently been wanting more options:

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