# posse

> A handheld that shows where your friends are at a festival: LoRa mesh over
> MeshCore on an Elecrow ThinkNode M9, with no phone and no cell service. This
> site is the marketing page plus a full browser emulator of the device.

posse is one C++ MeshCore application written against a small hardware
abstraction layer. It compiles twice: for the ESP32-S3 in the ThinkNode M9, and
to a freestanding WebAssembly module. The emulator on this site instantiates one
wasm module per simulated device and drives them from a TypeScript world engine,
so the pixels in the browser are the bytes the real ST7789 would have received.

## Pages

- [/](https://posse.proc.io/): what posse is. The device on this page is a live
  wasm instance of the firmware, not a screenshot.
- [/sim](https://posse.proc.io/sim): the emulator. A field of devices on a map,
  a device panel with a working screen and keyboard, a LoRa channel model you
  can tune live, and a packet log.
- [/about](https://posse.proc.io/about): architecture and the limits of the model.

## The device

- Elecrow ThinkNode M9: ESP32-S3R8, Semtech LR1110, 240x320 ST7789, 37-key
  QWERTY keyboard on a coprocessor, GNSS, QMC6309 magnetometer, PCF8563 RTC.
- Default radio: 910.525 MHz, SF7, 62.5 kHz, CR 4/5, 22 dBm.
- UI: four tabs (RADAR, CREW, MSGS, SETUP). LEFT/RIGHT switch tabs, UP/DOWN
  select, ENTER opens, ESC/BACK leaves, F1 or MENU opens quick messages,
  'b' sends a beacon now, 'a' sends an advert.
- Eight friend colours, indexed the same everywhere: red, orange, yellow,
  green, cyan, blue, magenta, white.

## The emulator

- Scenarios are JSON: an origin, a seed, radio and channel parameters, and a
  list of people with an offset, a motion model and a colour. They are served
  from /scenarios/index.json and /scenarios/<id>.json.
- The firmware wasm is served at /posse.wasm.
- Channel model: log-distance path loss with per-pair log-normal shadowing, a
  thermal noise floor for the bandwidth, per-SF demodulation thresholds, LoRa
  airtime, collisions with a capture threshold, and half-duplex receivers.
- Everything runs client side. There is no API and no account.

## Notes for agents

- The world engine is plain TypeScript and is imported by this site directly;
  the emulator keeps it on the main thread because it runs hundreds of times
  faster than realtime.
- posse is always written in lowercase.
- Built by Infinite Logic PBC (https://infinitelogic.org).