← Rizkin Labs Instruments · v2

The Bench.

Instruments built because the work needed them, then made public. Specification and release across twelve pharmacopoeias, pharmacokinetics and buffers, optics and acoustics, espresso and diving, and simulations that solve real physics as you watch. Every one runs locally, nothing you measure leaves the device, and each installs to a home screen and works with no signal at all.

caching

Full instruments

The sextant.

Celestial · offline

A working nautical almanac and sight reduction computer that needs no signal. An auto mode walks the whole procedure and puts an artificial horizon over the camera; or shoot by hand with the phone's inclinometer, or type in a reading from a real sextant, and get a position by least squares. Install it to the home screen and it runs with the radio off.

guided sightcamera HUD58 nav starsWMM2025intercept methodinstalls offline
Open the sextant →

The listening post.

Signals · WebUSB

A browser has exactly one wideband receiver, the microphone, and everything else is walled off on purpose. So this probes what the device will actually let a page hear, puts a real analyzer on the band you do get, and drives an RTL-SDR over WebUSB for the rest.

capability probegrid frequencyultrasonic beaconsDTMF & morsertl-sdr
Open the listening post →

The optical bench.

Camera · metrology

Three instruments that treat the camera as a photometer. A photon transfer curve for what the sensor's noise is made of and how many stops it really has, a slanted edge for what the lens actually resolves, and Beer-Lambert absorbance with a calibration curve for what is dissolved in a cuvette.

photon transferISO 12233 MTFBeer-Lambertdynamic rangeinstalls offline
Open the optical bench →

The dive planner.

Decompression

Buhlmann ZH-L16C with gradient factors, the algorithm inside a modern dive computer, written out where you can watch it work. Sixteen tissue compartments loading and off-gassing, a live ceiling, a stop schedule, and the gas planning that decides whether any of it is survivable. It also keeps a dive log on the device: import what your computer's app exports, build a profile by dragging it, and take it away as a spreadsheet. A teaching instrument, not a dive computer.

16 compartmentsgradient factorsdive logimports UDDFexports .xlsxinstalls offline
Open the dive planner →

The visualiser.

Audio · WebGL

Twelve ways to look at the same sound, full screen and built to be stared at. Nine of them are a spectrogram displaced on the GPU, so frequency across, time toward you and level as height becomes a landscape, a tunnel, a canyon, a mandala, a planet, a torus, a whirlpool, a twisting ribbon, or a flat torus in four dimensions that squares off into a tesseract and turns through itself. The other three draw the geometry the notes have rather than the spectrum does: pitch as a helix where one turn is an octave and a chord is a shape you can recognize, rhythm as a spectrum of how fast each band is pulsing, and the stereo image with time running away from you. Feedback trails, bloom and chromatic aberration on top, driven by an onset detector. Every height is still a measurement, and the maths is written out in the page.

twelve shapesconstant-Q, 84 notesmodulation spectrum4D projectiononset driveninstalls offline
Open the visualiser →

The exoplanet census.

Astronomy · live data

Every confirmed planet outside the solar system, pulled live from the NASA Exoplanet Archive by your own browser. The points are the easy part. The interesting thing is the empty regions, because most of them are empty for reasons that have nothing to do with what is out there: turn on the transit depth, transit probability and radial velocity contours and the boundaries of the sample land exactly on lines drawn by our instruments. The radius valley and the Neptune desert are both in here, along with everything derived from first principles rather than read from a column.

live NASA datadetection bias contoursradius valleyNeptune desertsolar system to scaleinstalls offline
Open the exoplanet census →

The room tuner.

Acoustics · mic

Measure a room properly. A swept sine deconvolves to the impulse response, which gives reverberation time per octave to ISO 3382, the frequency response, and where your predicted modes actually landed. An auto mode runs the whole sequence and reads the result back in plain terms. Then it tells you what to fix, and refuses to pretend EQ can fix all of it.

guided runswept-sine IRT20 / T301/3 octave RTAmode overlaytime alignment
Open the room tuner →

Games

The swimmer.

Biophysics · game

A flight simulator for a bacterium. At Reynolds number 0.0001 water behaves like tar, inertia does not exist, and every instinct you have about moving through a fluid is wrong: stop swimming and you stop dead within the width of an atom. Purcell's scallop theorem is here to be failed at, then beaten with a corkscrew. Then you steer a cell to a sugar source the only way a cell can, by choosing when to give up on a direction, and race twenty four of them that do it properly.

scallop theoremStokes dragBrownian rotationrun and tumbleinstalls offline
Open the swimmer →

The bloodstream.

Haemodynamics · game

You are a nanoparticle in a small artery, with no engine, no rudder and sixteen forks between you and the tissue. The tree is built from Murray's law alone and every number falls out of it: the velocity, the wall shear that barely moves in sixteen generations, and the fact that blood in a capillary flows almost as easily as water. At each fork the fluid has already decided, and all you can do is be on the right side of the dividing streamline when you arrive. Then get to the wall and try to stick before the shear tears you off.

Murray's lawPoiseuille flowFahraeus-Lindqvistplasma skimminginstalls offline
Open the bloodstream →

Live & interactive

Waterfall.

Spectrogram · mic

A full FFT waterfall, frequency across, time falling down, loudness in the palette. Point it at a stack and watch the sub-bass bloom.

Spectrum analyzer.

Signal · mic

Live microphone FFT on a log axis, room modes, tuning, and the mains hum you pretend not to hear.

The tuner.

A = 440

Chromatic, play a note, the needle does the judging. Audio never leaves the browser.

·

Kármán vortex street.

CFD

A live D2Q9 lattice-Boltzmann fluid shedding vortices past a cylinder, the Strouhal number, caught in the act.

click the flow to perturb it → kicks off shedding −ω vorticity

Reaction–diffusion.

Turing

Gray–Scott: two reactants diffuse and react until spots, stripes, and coral emerge from noise.

Click and drag on the field to paint reactant v.

Fourier epicycles.

DFT

Draw a closed shape with a finger. Its Fourier transform turns it into a stack of rotating circles, each turning a whole number of times per lap, and the pen on the end retraces exactly what you drew.

Double pendulum.

Lyapunov

Two pendulums launched a hundred millionth of a radian apart. Watch how long they agree, then watch the exponent that measures exactly how fast they stop agreeing.

Fractal frost.

Aggregation

Particles wander in from nowhere and stick where they first touch. Tips catch wanderers before the hollows do, so tips grow, and the result is a fractal that measures its own dimension.

The Ising model.

Phase transition

Spins on a lattice, each one only wanting to agree with its neighbours. Drag the temperature down through the critical point and watch order appear out of nothing.

Quantum tunnelling.

Schrödinger

A Gaussian wavepacket thrown at a barrier it does not have the energy to cross. Some of it goes through anyway. Split-step Fourier, solving the real time-dependent equation.

Chladni figures.

Modal

Sand on a driven plate, walking away from the antinodes until it is stranded on the nodal lines. Sweep the frequency by hand, or let the microphone drive it and sing at the plate.

Harmonograph.

Lissajous

Two frequency ratios, four damped pendulum swings. Signal processing that thinks it's jazz.

Chem & pharma

The specification builder.

CMC · regulatory

Describe a drug product and it builds the release specification that follows from its form, its route, its dose and where it is going. Twenty one modalities, from a tablet through an antibody drug conjugate and an mRNA particle to an autologous CAR-T, against a library of a hundred and twenty one tests. Twelve launch regions, each with the pharmacopoeia that governs there and the release obligations that come with it. The ICH thresholds are computed from the dose rather than quoted, so the impurity limits, the mutagenic acceptable intake, the solvent and elemental concentrations and the endotoxin limit all move when you change it. Every row says whether its criterion is fixed by the pharmacopoeia, derived from ICH, or yours to justify, and where a region's chapter numbering is not carried here it says so rather than inventing one. It also checks the product against itself, because a specification can be internally perfect and still describe something that cannot exist: an autologous cell therapy has no second dose to withdraw from a multi-dose vial, a live biotherapeutic that passes a sterility test is dead, and an intrathecal product cannot carry a preservative.

121 tests21 modalities12 launch regionsICH thresholds computedregional deltas flaggedcoherence checksCSV and printinstalls offline
Open the specification builder →

Pharmacokinetics.

Half-life

Steady-state accumulation for repeated dosing, where the drug piles up, and when it stops.

Buffer pH.

Henderson–Hasselbalch

pH from pKa and the conjugate base/acid ratio, or solve the ratio for a target pH.

Dilution & molarity.

Bench math

C1V1 = C2V2, or grams to molarity. Leave one field blank (or 0); I solve for it.

Engineering & sound

Dimensionless numbers.

Transport

The ratios that run the universe, pick one.

Engineer's converter.

Units

Pressure, temperature, flow, viscosity, the ones that actually come up.

Sound & space.

Acoustics

Frequency ↔ note ↔ wavelength, and your room's first standing waves.

Photography & optics

The surface record.

Photometric · provenance

A painting has a texture no copy of it shares: the weave under the ground, the ridge a loaded brush leaves, the crack that opened in 1904. Prop the phone facing it, put a marble or a ball bearing in shot, and move a torch slowly around while the back camera watches. The highlight sliding across that ball says exactly where the light was in every frame, which is enough to solve for the way the surface slopes at every point, and its known diameter fixes the scale so two sessions taken from different distances compare directly. Twenty four patches of the relief are committed to a domain separated SHA-256 Merkle root and signed. Two completely different sweeps of one painting agree at 0.98 and a different painting scores 0.06. The score is read at one transform all the sites agree on rather than letting each hunt for its own best offset, because the best of four thousand correlations is not a correlation any more, and that is the difference between rejecting a second canvas off the same bolt and accepting it. A screen lamp mode is there too, for when you have nothing but the phone.

highlight RTIphotometric stereoa marble for a light probeMerkle rootECDSA P-256consensus alignmentnothing uploadedinstalls offline
Open the surface record →

Below the waterline.

Optics

Pressure, light, color, gas, and time, the physics of a dive.

Chasing light.

Solar

Sunrise, sunset, and golden hour for any spot on Earth.

Flicker meter.

Rolling shutter

Your sensor scans rows in sequence, so a flickering light writes stripes into a single frame. Read the stripe pitch and you have the flicker frequency of any lamp, screen or LED, plus how deeply it modulates, judged against the standard that says whether it will give people headaches.

Depth of field.

Optics

Hyperfocal distance and the sliver of the world that lands sharp.

Kitchen

Espresso dial-in.

CFD dept.

Enter a shot; get ratio, flow, and what to change next.

The cooling curve.

Thermo

Newton's law of cooling, when is it actually drinkable?

The rating plate. What this device is, which sensors it will let a page read, and how hard the simulations above should push. Measured here, kept here, sent nowhere. device & profile open →

For curiosity and the darkroom, not for dive planning, medicine, or process safety. Trust your tables, your validation, and your palate.