skizzophrenic/SquachWatch-CYD

Surveillance-device detector for the ESP32-2432S028R ("Cheap Yellow Display"), and a growing list of other ESP32 boards.

SquachWatch-CYD sniffs WiFi and Bluetooth for known wireless signatures of Flock Safety cameras, Axon body cameras, recording glasses, card skimmers, AirTags, drones, proximity beacons and pentest hardware. On the 2.8" CYD it listens on 2.4 GHz and runs standalone on the bare board — no PC, no extras, just plug it into USB. A few other boards hear more: the NM-CYD-C5 scans 5 GHz as well, and the T-Watch S3 listens to LoRa, with GPS on the S3 Plus (see Boards).

The UI is a vaporwave-themed take on the SquachWare aesthetic: matrix digital rain, Squachy the mascot, full-screen dramatic ALERT overlays, and the glitchy SquachWatch wordmark.

That is the firmware itself, not a mockup.
Every frame above was rendered by the same C++ that runs on the board, compiled for a PC.
Click it to drive it in your browser →

Every hardware prefix in the firmware was checked against the IEEE registry rather than against other detectors. Of 97 rows: 33 High, 4 Medium, 60 Low.

That grading matters most on FLOCK, where exactly one of 49 prefixes is registered to Flock Safety and the rest are the generic chip and module makers' blocks they build on (Espressif, Liteon, Silicon Labs and friends) — real evidence, shared with every dev board on earth. ALERT FILTER is a minimum-confidence gate, so setting it to High keeps a passing ESP32 in the log without taking over the screen.

The audit also removed 00:0E:58, which sat here for eleven releases labelled "Vigilant" and is registered to Sonos. Every speaker in range was being logged as a plate reader.

IBEACON ships switched off — not a judgement about importance, one about volume. One shop can put more beacons in range than this device would otherwise see all week. It is one tap away in TYPE FILTER.

Not sure which to buy? The 2.8" CYD (ESP32-2432S028R) is about $15 and is the board everything here is designed on: built-in 320×240 TFT, resistive touch, a microSD slot and an RGB light, and nothing else to add. No GPS, no extra modules; the board is the whole device. Every board below is on the web flasher. BETA means it runs the whole firmware but has had fewer hours on it. The longer answer is in docs/FAQ.md.

Each board has its own build in platformio.ini, one [env:...] each, with what is and is not confirmed on it.

No build tools, no IDE, no cloning anything — flash a board straight from your browser:

https://squachwatch.com/

Works in Firefox, Chrome, Edge, or Brave on desktop. Pick your board from the list (it is grouped by family, and there is a box for the code printed on the back if you are not sure which you have), plug in, click Connect & Install, done. A T-Watch has its clock set for it once the install finishes.

Three steps:

1. Install PlatformIO (CLI or VS Code extension).
2. Clone the repo:

   git clone https://github.com/skizzophrenic/SquachWatch-CYD
   cd SquachWatch-CYD

3. Build and flash:

   pio run -t upload

   For a board that is not the default three, name its build, e.g. pio run -e freenove-s3 -t upload.

The first build pulls the TFT_eSPI, XPT2046, and NimBLE-Arduino libraries; after that it's incremental.

A full beginner-friendly walkthrough is in docs/BUILD.md.

Your settings, PIN and squad stay put whichever way you go.

Every over-the-air update is signed, and a board refuses anything not signed by this project or not built for its own board. A new version starts on trial: if it crashes or loses power in its first 30 seconds the board goes back to the one it had, and SWITCH TO on the same screen goes back by hand.

When a WiFi update can't get through, the screen says which thing is in the way: a hotel or school network that wants a sign-in page first, a network that blocks the site, a router that can't look the name up (the board then tries the site's fixed addresses), or the site being slow, down or secure-only. Each message ends in a short code in brackets to quote if you ask for help. Those messages arrived in v1.33.0, so a board on anything older that can't reach the site needs one USB install to get them.

Two ways, neither of which installs anything. At boot, a board with a saved WiFi network joins it for about a second, asks squachwatch.com for the latest version of its own build, and lets go again, all before Bluetooth starts; UPDATE CHECK on the SYSTEM page turns that off. And every board's hello to its squad carries its version, so a board that hears a member running something newer knows without touching WiFi. Either way Squachy says it once on the main screen, the SYSTEM row reads UPDATE, and UPDATE FIRMWARE names the version until you install it.

WIFI NETWORKS on the SYSTEM page is where the board keeps the networks it knows: up to six, with USE marking the one it tries first. ADD picks one from a scan and takes the password on the board's keyboard; it is not checked by joining, since joining means giving Bluetooth up until a restart, but at the next boot check, and each row then says how that went: joined, wrong password, or not found. At boot the board scans, joins the USE network if it is there and otherwise the strongest saved one that is, so home and work both just work. The update flow does the same, and only shows its own list when none of the saved networks is in range. REMOVE takes one off the list.

1. Plug the CYD into USB-C.
2. The splash runs for a second and a half, stamped with the build's own version (from git describe, so a working-tree build says so).
3. The main screen appears: your chosen background, Squachy, and a counter button along the top for each kind of thing in range. He says something reassuring every thirty seconds.
4. The three soft buttons at the bottom:
   • [ SCAN ] — return to the main (idle) screen.
   • [ LOG ] — open the detection log, each device once. It survives a restart: about 1,800 sightings are kept in flash.
   • [ DESK ] — desk mode: the big clock, with Squachy under it.
   • On the LOG screen the third button is [ CLR ] — wipe the log and return.
5. When something is detected, the device flashes a full-screen ALERT: a header strip in the detection's own colour with the type in the Bangers face, a data plate with the vendor, the device's own name where it broadcasts one, its MAC and a signal meter, and a gauge showing what was found with the instrument grid over it. Tap anywhere to dismiss early, or it clears itself after 10 seconds. A device on your watch list gets LOCKED ON instead, which waits for your tap (see Alert controls).

If a microSD card is present, every detection is also appended to squachwatch-<day>.log (CSV: ts,type,rssi,mac,channel,vendor,ssid).

There is no GPS (except on the T-Watch S3 Plus, which sets its clock from it when it has a fix), and the board never joins a network to scan. But it does join one for the update check at boot, and for UPDATE OVER WIFI, and the clock rides along: one NTP round trip while the radio is up anyway, about a second. The zone is yours to pick, and there are three ways: the web flasher's Set Time & Zone button sends this computer's clock and zone down the same cable right after flashing; the first time the clock is set with no zone chosen, a card on the main screen asks, with the live time in the zone it shows so you can see when it's right; and TIME ZONE on the DESK MODE page changes it later. Daylight saving takes care of itself. Without a saved network the clock can still be set over serial with a TIME <epoch> line at 2,000,000 baud, and ZONE US EASTERN sets the zone the same way. And every squad hello carries the sender's clock and zone, so a board with neither takes them from the first member it hears: update one board by USB and the rest of the squad know the time within a minute of meeting it. Until the clock is set, timestamps count from boot. The board keeps a note of the time in flash every ten minutes, and a cold boot with no clock starts from that note: not the right time, since nobody knows how long the power was off, but never earlier than the note, which keeps the day count honest. Such a clock is used for the date only; the LOG times, the night tag, the hour lines and the desk digits wait for a real answer.

Once it is set, the LOG shows the real time of each catch (or the date, for one from another day); the alert card says AT NIGHT for anything caught between eleven and five, and Squachy's line sharpens to match; he says hello once a day with the date in it, knows whether it's Monday, lunch, the three o'clock slump or two in the morning, and counts the days since the board first knew the date: a week, a month, a hundred days, a year.

BANTER on the APPEARANCE page sets how much he talks when nothing is happening: IMPORTANT (idle chatter off; he still speaks for a catch, a message, a newer release and the daily hello), LESS, NORMAL or MORE. The set pieces two Squachys act out follow the same setting.

DESK MODE in Settings turns the board into the thing beside the keyboard: your background, the date and the time in big seven-segment digits on a plate over it, Squachy underneath doing what he does, and a focus timer. FOCUS 25 starts twenty-five minutes: the scene clears, he goes still and quiet, and when it runs out the light on the back goes green, he tells you to stand up, and a five-minute break counts down on its own. A tap on the running timer stops it. The desk keeps its own background, picked with a tap at the left or right edge and remembered separately from the main screen's. Detection keeps running behind all of it: a catch shows as a small card by the buttons instead of the full ALERT (tap it for the full card), and a squad message stands where Squachy stands, as a polaroid of the sender's Squachy with his name in the margin, the message on a note beside it and the time it came, until you tap it. The power saver never dims this screen.

A detector that cries wolf gets switched off, so there are a few ways to tell it what you care about. Apart from TYPE FILTER, none of these stop anything being scanned, counted or logged; they only decide what takes over the screen.

Settings → SECURITY puts a PIN on the board: 4, 6 or 8 digits, with LOCK AT BOOT, AUTO-LOCK (when the screen sleeps, or after 1 to 30 idle minutes), ALERTS LOCKED (what an alert shows while locked: FULL, TYPE ONLY or NONE) and WIPE AFTER 10 wrong guesses. It says plainly what it is for: people at the table, not someone with a USB cable.

A DURESS PIN is a second PIN of the same length. Typed at the lock screen, it erases the squad phrase and messages, the ignore list, the saved WiFi passwords and the log (in flash and on the SD card, and the watch's GPS log), then restarts quietly, with the status light dark and no splash, and comes back unlocked on the main screen. To anyone watching, it was an unlock.

PRIVACY MODE (Settings → SYSTEM) is for filming and screenshots: addresses show as AA:BB:CC:XX:XX:XX, and device and network names are cut to three characters. It changes the screen only; nothing stored changes.

• POWER SAVER (Settings): the LOW POWER master switch, then SCREEN TIMEOUT, DIM TO, IDLE FRAMES and IDLE AFTER (a slower frame rate once nothing is happening), CPU CLOCK and WAKE ON ALERT.
• CHARGE MODE (Settings, or hold BOOT on the CYD boards): radios, status light and screen off while it charges.
• BOOT on the CYD boards: a short press turns the screen off, and only another press turns it on (POCKET MODE: a touch won't, so a board in a pocket stays dark). Alerts still light it for their card, then it goes dark again.
• The battery lamp on the Freenove ESP32-S3 2.8" and 3.5" and the T-Watch: a lava lamp under the menu button, filled to the charge. Bubbles and a rainbow on the cable, a flicker under 10%. Boards with no battery don't show one.
• POWER OFF on the Freenove ESP32-S3 2.8" and 3.5": hold BOOT for three seconds; press it to turn the board back on. (CHARGE MODE is on the Settings list there.)
• The speaker on the same two boards: SOUND in Settings is OFF, ALERTS or ALL, with VOLUME on - and + buttons. Quiet at night and while the screen is dimmed, except for a watch-list hit.
• LAST RUN (Settings → SYSTEM): how long the previous power-up lasted.

The LilyGo T-Watch S3 and S3 Plus (BETA) run the whole firmware on a 240×240 screen, plus a few things only a watch needs. They live under WATCH SETTINGS, the first row in Settings.

• The crown turns the screen off and only the crown turns it back on (POCKET MODE), and alerts buzz on your wrist (BUZZ: OFF, HIGH, MED or LOW).
• LoRa, on both models and receive only: Meshtastic and MeshCore at once, with public channels decoded into LORA CHATS, one tab per network. LORA picks BOTH, MESHTASTIC, MESHCORE or OFF, and the band (915 or 868 MHz) follows your time zone. A LORA NEW pill on the main screen says something arrived. The radio research behind it is in docs/LORA.md.
• TAGS + RINGS: LOG ONLY by default, so trackers and Ring cameras are logged without waking the screen or buzzing. ALERT puts them back.
• Wardriving, S3 Plus only: WARDRIVE switches the GPS and its log on together. WiFi networks (with their security) and Bluetooth devices are logged with position, altitude and accuracy while there is a fresh fix, kept in the watch's own flash across restarts. DOWNLOAD WIGLE FILE on the web flasher (desktop Chrome or Edge) saves it as a file for wigle.net.

The RGB LED on the back of the 2.8" CYD (on the front of the RL Phantom, and a WS2812 on the Freenove ESP32-S3 2.8") tells you what the screen is doing without the screen. A slow breathe in the theme's colour when nothing is happening; three flashes and a hold in the detection's own colour when something is, for as long as the alert card is up; a double-blink for an unread message; a blip when a squad member walks on; cyan while an update downloads and green or red for how it went. It goes dark on the lock screen and through a wipe, so a duress restart looks like any other restart from the back too.

Settings → APPEARANCE → STATUS LIGHT: the master switch, alerts and messages on or off, idle breathe or solid or off, an idle colour that follows the theme, the background, or one of nine fixed colours, brightness in seven steps, and a TEST row that plays the lot in six seconds. Boards whose LED pins have not been checked (the AWOK and the 3.5") compile it out and say so on that screen.

Work in progress. It is in this release because it works — two boards find each other and each draws the other's Squachy — but it has had days of testing, not months. Both halves are off until you turn them on, and one of them costs you something; the device asks before it lets you near the switch.

Two SquachWatches in range of each other notice, and each one draws the other's Squachy as a visitor. He walks in, they high five, they stand around talking — now and then breaking into one of the thirty-odd emotes on their own, a pie fight, a coin toss, a selfie, a dance-off, the same one on both screens with the same result — and he goes home when the other board does. His outfit, his shades and his name all travelled over the air in a twenty-byte BLE advert. The name is one row, NAME under SQUACHMESH: a curated one until somebody types one on the payphone, where SHUFFLE steps through the curated list for anyone who would rather not type. Whichever it is, the visitor wears it on a sticker on his chest.

That was where it started. Since then the squad has picked up messages, and thirty-five emotes you can send from the message screen; a CROWD setting that puts up to eight boards on screen together, roaming rather than standing in line; joining without typing; a roster and a fox hunt; UPDATE SQUAD, one board telling the rest to update; and HEADS-UP. That last one means a serious catch on your board (Flock, Axon, a skimmer, Raven, a plate reader, a deauth flood, an evil twin or hacking gear; never trackers) shows on your squad's screens as an amber banner for eight seconds, at most once a minute. HEADS-UP in the SquachMesh menu switches it off.

It is deliberately not a network. No pairing, no connection, no acknowledgement, no retry — a broadcast that says who is here, and anybody in earshot may or may not catch it. A peer is recognised inside the scan callback and returns before the signature tables ever see it, so two of these can never set each other off.

Settings → SQUACHMESH, and it asks first. DETECT is receive-only: you see other people's Squachys and broadcast nothing at all. TRANSMIT is the half that makes you visible, and a full-screen warning stands in front of that menu spelling out what goes out, how often, and what somebody with a scanner can reconstruct from it — a fixed address that never changes is a trail of where you have been. Nothing is transmitted until you have read that and chosen YES.

That warning is not a formality. Broadcasting a stable identifier at strangers is the exact behaviour this device exists to catch other people's hardware doing. Offering it is defensible; switching it on quietly would not be.

Two SquachWatches that share a five-word phrase can message each other: one of 24 ready-made lines, or up to 48 characters typed on the payphone or the QWERTY board. A message arrives as a red bubble with the sender's name in it, so it is never mistaken for the Squachys' own chatter, and nothing is sent until you have confirmed it.

Settings → SQUACHMESH → MESSAGES, then PHRASE: one of you ROLLs five words and reads them out, the other ENTERs the same five. Setting a phrase freezes the screen for about three seconds on purpose — it is 20,000 rounds of PBKDF2, which every guess at your phrase has to pay too. A seven-card tutorial runs the first time MESSAGES is switched on, and the ? on the message screen replays it; it never transmits anything.

Messages are AES-128-CCM, keyed from the phrase, with a nonce that cannot repeat even across a crash, and every board checks its cipher against frames made by an independent implementation at each boot. What stays visible is that you sent something, and when: the contents are encrypted, the fact of a message is not.

The typed phrase is the reliable way in and always will be. The convenient way is ADD, beside INVITE and HUNT on the SQUAD screen (the +N next to a visitor). Pick a board in range and tap it; their board asks them whether they want in. Both screens then show the same four digits, which the two of you compare out loud, and the phrase goes across sealed under a key that exists for that one exchange and no other. The digits are derived from both boards' keys, so a third board in the middle pretending to be each of you to the other leaves the two screens disagreeing — say NO and nothing was sent. The new member's board answers with a sealed hello the moment it has the phrase, the inviter's shows ADDED, and both drop back to the main screen on their own. If nothing comes back, the inviter's screen says so and offers to show the phrase for typing.

Boards that have shown they hold your phrase read MEMBER on that screen, and ADD only offers itself to strangers. Anyone with the phrase can invite anyone; the phrase is the membership, and leaving somebody out means a new phrase on every board.

Settings → SQUACHMESH → SQUAD is the roster: everybody who has ever been heard holding your phrase, here or not, up to sixteen, kept across restarts. Each member shows in the outfit from their latest advert, with how many separate times you have met, those in range first. INVITE works when they are here, AWAY says when they are not, and FORGET drops them after asking once; they come back the next time they are heard with the phrase. A new phrase clears the roster, because a new phrase is a new squad.

HUNT on either SQUAD screen aims HUNT MODE's signal gauge at that board. It is the same meter the detector uses for a tag: no compass, so you turn your body and walk toward where the needle does not fall. Two readings in a row at arm's length and the gauge says CAUGHT!, Squachy bounces, and the light on the back flashes green. The fox needs TRANSMIT on; the hunters need DETECT on, which they have if they can see the SQUAD screen at all.

SHOW PHRASE on the PHRASE screen is on by default. Off, the five words become dashes, the board never prints them, and the only way into the squad from that board's side is ADD TO SQUAD, in person.

• Arrows on NEARBY. Each device shows a green up-arrow when it has come closer since its last reading and a red down-arrow when it has moved away; under four dB of change shows nothing, which is what a still device does.
• First of its kind. The first time this board ever catches a type, the card says so and Squachy marks the occasion when you get back to him.
• FILL on the message screen. Eight openings that end in a blank, MEET AT, I'M AT, BACK IN and the rest; pick one and the keyboard opens with it typed.
• Read receipts. When a squad member opens your message their board says so, and yours shows a READ toast with their name. A reader with TRANSMIT off can't send one, so you see sent and never read, which is the truth.
• Banter about something. Two Squachys now talk about the weather on screen, what was caught earlier, each other's outfits, how many times they've met, the squad's size, and the length of the day, one exchange in three, when there's something to say.

Settings → SYSTEM → UPDATE FIRMWARE → UPDATE SQUAD tells every board in range with your phrase to install the version this one is running. Each of them shows a thirty-second countdown with SKIP, joins WiFi, installs the signed release from squachwatch.com, restarts, and reports back by name to the board that asked. The sender can share its own saved network with the nudge, sealed with the phrase; the receiving boards use it once and forget it.

A board listens because it holds your phrase, which is the same trust it already gives you for messages and the invite; REMOTE UPDATE on its SECURITY screen turns that off for anyone who wants it off. A locked board ignores the whole thing regardless. So the order on release day is: update one board by hand, then UPDATE SQUAD from it.

None of this finds anything. All of it is why you leave him on.

And he can be thrown: press and hold him until he notices, drag, and let go while your finger is still moving. Some of the pets can be thrown too. They keep count.

Squachy has nineteen costumes. Most are earned by detection count; ten are hidden behind things nobody tells you about, on the background they belong to, and one of those is a punishment rather than a prize. Two of them are in the animation at the top of this page.

No fabricated marketing shots, which was the promise here before there was anything to show. Every panel above was drawn by the firmware, one render per costume, and the labels are read out of the source rather than typed next to it — so a renamed or newly added outfit cannot end up captioned wrongly. Regenerate with python3 make_gallery.py in sim/.

SquachWatch-CYD/
├── platformio.ini
├── README.md
├── LICENSE
├── docs/
│   ├── FAQ.md                    (what it does, hardware, legality)
│   ├── DESIGN.md                 (the contract — single source of truth)
│   ├── BUILD.md                  (friendly walkthrough)
│   ├── PINOUT.md                 (CYD pin map)
│   ├── DETECTIONS.md             (per-signature provenance)
│   ├── CROWPANEL7.md             (the 7" CrowPanel: setup and testing)
│   ├── NM-CYD-C5.md              (the ESP32-C5 board: esptool route, every pin)
│   ├── LORA.md                   (LoRa research and the decoders behind it)
│   ├── IDEAS.md                  (things worth building, with their cost)
│   └── SQUACHWARE-AESTHETIC.md   (CSS → RGB565 mapping)
├── include/
│   ├── state.h                   (DetectionType, Detection, Confidence)
│   ├── theme.h                   (palette, backgrounds, icons, chrome)
│   ├── signatures.h              (the tables and their lookups)
│   ├── detection.h
│   ├── remote_id.h               (ASTM F3411 decoder)
│   ├── clock.h                   (wall clock: NTP at the boot check, zones, the calendar)
│   ├── ignore_list.h             (per-device alert suppression)
│   ├── status_light.h            (the RGB LED and its rules)
│   ├── meshmsg.h                 (sealed frames: messages, emotes, nudges, invites)
│   ├── squachmesh.h              (the SquachMesh wire format -- read first)
│   ├── settings.h
│   ├── squachy.h                 (the mascot)
│   ├── bangers_font.h            (generated 1bpp display face)
│   ├── cyd_user_setup.h          (TFT_eSPI config for the CYD)
│   └── ui_*.h
├── src/
│   ├── main.cpp                  (setup/loop, state machine, touch)
│   ├── theme.cpp                 (backgrounds, per-type icons, chrome)
│   ├── squachy.cpp               (the mascot, his outfits and his lines)
│   ├── signatures.cpp
│   ├── detection.cpp             (WiFi promiscuous + NimBLE scan)
│   ├── remote_id.cpp
│   ├── clock.cpp
│   ├── ignore_list.cpp
│   ├── pet.cpp
│   ├── squachmesh.cpp            (SquachMesh encode/decode, no radio)
│   ├── meshtalk.cpp              (messages, the squad update, the invite)
│   ├── meshcrypto.cpp            (AES-CCM, PBKDF2, and X25519 for invites)
│   ├── status_light.cpp
│   ├── sd_log.cpp
│   └── ui_*.cpp
├── test/                         (host tests -- `make -C test`, no framework)
└── sim/                          (PC emulator — compiles src/ natively)
    ├── Makefile                  (`make` for the CLI, `make wasm` for the web build)
    ├── *.h                       (Arduino/TFT_eSPI/NVS shims)
    ├── make_readme_demo.py       (renders the animation at the top of this file)
    ├── make_demo.py              (the older background tour)
    ├── make_mesh_demo.py         (renders the SquachMesh clip above)
    ├── make_gallery.py           (renders the outfit sheet above)
    ├── make_social.py            (renders the repo's social preview card)
    └── web/                      (the browser build)

GNU General Public License v3.0 (GPL-3.0). See LICENSE.

• Flock Safety OUI research, and the Flock and Raven signatures added in v1.24.0: @NitekryDPaul, DeFlockJoplin, colonelpanichacks/flock-you (MIT).
• Axon / skimmer / SSID prefix data: compiled with assistance from Gemini (Google), expanded against public sources.
• AirTag manufacturer-data format: public Apple FindMy spec. The AirTag payload check is ported from nyanBOX by jbohack (MIT).
• AWOK 2.4" board port (ESP32-Marauder V6.1 hardware): bkbroiler, who did the actual pin-mapping and shared-bus touch-calibration work that made this board possible.
• Elecrow CrowPanel Advance 7.0 port, the ESP32-S3 WiFi fix that keeps the S3 boards from waking up deaf, and the LoRa radio driver and every decoder on the T-Watches: DH5DAX.
• RockBase NM-CYD-C5 port, and its 5 GHz scanning: quietradio.
• GPS and wardriving to the SD card on the CYD, and the SD log's dates (PR #46): jotra7. The Marauder V8 wardrives with it.
• The Marauder V8 itself, and the Marauder project it comes from: justcallmekoko.
• Freenove ESP32-S3 Display 2.8" port: greasy-electronics.
• Freenove 3.2" pin work: DevOpsDAdams.
• 3.5" capacitive (ESP32-3248S035C) build: VV-B0Y.
• The emulator building on macOS, and its incremental build: aroth.
• Testing every single build, boot loops and green skies included: Houdini.
• Bug reports that found real bugs: rrahmani (Remote ID never caught a real drone; photos and a diagnosis of the 3.5" drawing half its screen twice), bradshapiro59 (phantom Flock alerts from garbage Bluetooth names; Bluetooth addresses printed back to front) and philchamp51 (that same 3.5" bug).

Shipping. Releases are cut by pushing a v*.*.* tag; the flasher above is rebuilt and redeployed by the same CI run, so the web flasher always matches the newest release.

Detection is reliable for the high-priority targets (Flock, Axon, skimmer, camera glasses). Remote ID and iBeacon are exact-format matches. Raven, generic ALPR and the Google tracker network are best-effort — see docs/DETECTIONS.md for per-signature provenance and the confidence each one earns.

Verified on real hardware. There is also a PC emulator in sim/ that compiles the actual src/ against shims, and a host test suite in test/ (make -C test) covering the decoders, the signature tables and the emulator's own fidelity to the display library.