Local HTTP API

The S3 and ESP32-CAM each host an HTTP server at their own Wi-Fi address. Obtain those addresses through the setup menu. J6 supplies camera power; camera requests travel over Wi-Fi.

Except for the S3’s HTML viewer shell, requests require Authorization: Bearer <api_token>. Both boards use the shared local token saved during setup. This is separate from the central telemetry token. Local HTTP does not encrypt the token; this interface is intended for the isolated bench network.

Routes and responses

Board	Method and path	Success	Other defined responses
S3	`GET /`	200 HTML viewer shell; data requests still need a token	—
S3	`GET /status`	200 JSON, fusion and protection status	401 unauthorized
S3	`GET /config`	200 JSON, applied control configuration	401
S3	`PUT /config`	200 text, saved and local re-arm required	400 invalid body/limits, 401, 409 version conflict/update busy, 500 storage failure
S3	`POST /relay/open`	200 text, relay opening	401
S3	`GET /fused.bmp`	200 binary BMP	401, 503 unavailable/stale fusion
Camera	`GET /capture`	200 binary JPEG	401, 503 no fresh frame/camera unavailable

Error bodies are plain text. Do not parse every response as JSON. The camera does not implement /status; use USB info for its settings, identity and IP address. There is no HTTP close/re-arm endpoint.

Read status

For example, use Postman’s firmware/get_status request, or send:

GET /status HTTP/1.1
Host: 192.168.1.51
Authorization: Bearer YOUR_LOCAL_API_TOKEN

/status places fusion and protection fields together at the JSON root. The outgoing telemetry payload instead nests fusion metadata under vision.

Fields	Meaning
`ready`, `reason`, `synthetic`	Fusion availability, explanation and demo indicator; `ready` does not mean the relay is armed
`installation_id`, `camera_id`, `camera_frame_id`, `calibration_version`, `sequence`	Image identity, alignment version and publication sequence
`display_min_c`, `display_max_c`	Overlay color scale in °C
`regions[]`	Region ID, `supported`, `ambiguous`, `samples`, `boundary_samples`, `max_c`, `mean_c`, `rise_c_per_min`
`current`, `temperature`	AC RMS amperes and native thermal maximum °C; null when unavailable/stale
`relay_state`, `protection_state`, `protection_reason`	Open/closed output, disarmed/armed/tripped controller and reason
`config_version`, `commissioned`, `storage_ok`	Applied configuration and persistent-storage state
`current_sensor`, `arc_detection_available`	CT description and false for the unimplemented arc detector
`events[]`	Up to 16 transitions: `sequence`, `boot_id`, `uptime_ms`, `state`, `reason`, `current_a`, `temperature_c`

Unsupported or stale region temperatures are null. samples counts native sensor pixels, not interpolated image pixels. Check supported before using a region measurement. Events use boot-relative time and can include null measurements.

Replace control configuration

First read GET /config, then send all five fields with a version greater than the applied version. The following body is an example; use a newer version for your board.

{
  "version": 2,
  "commissioned": false,
  "current_limit_a": 0.8,
  "temperature_limit_c": 60,
  "current_scale_a_per_v": 111.1111
}

Field	Validation
`version`	Integer 1–4294967295, strictly increasing
`commissioned`	Boolean; false keeps the controller uncommissioned
`current_limit_a`	Greater than 0 and at most 1 A
`temperature_limit_c`	20–100 °C
`current_scale_a_per_v`	50–200 A/V; actual calibration is installation-specific

Send Content-Type: application/json. The body must be 1–512 bytes with exactly these five fields. An accepted update opens the relay, commits NVS, invalidates the current snapshot and resets the healthy re-arm interval. It replies Saved. Local re-arm required. Setting commissioned true does not close the relay. On 409, re-read configuration and resolve the version/update conflict. On 500, storage failed and the relay remains open.

Wi-Fi credentials and endpoint settings use the USB API, not /config.

Open the relay

Send POST /relay/open with authentication and no JSON body. The response is Relay opening; remote re-arm is not supported. A latched trip remains latched. State readback is updated by the protection task; use /status to observe it.

Retrieve images

GET /fused.bmp returns a top-down 24-bit 320 × 240 BMP with X-Fusion-Sequence. Match that header to a status sequence when associating metadata with a displayed image; the two requests are independent and may straddle a new publication. A missing calibration, unsupported pair or image older than 2 s results in 503.

GET /capture on the camera returns a fresh 320 × 240 JPEG, capped at 128 KiB, with:

Header	Meaning
`X-Camera-ID`	Configured camera identity
`X-Camera-Boot`	Random boot identifier
`X-Camera-Sequence`	Frame sequence
`X-Capture-Policy`	`fresh-after-request`

The camera discards earlier queued frames and tries a bounded number of captures. It returns 503 if it cannot provide a frame captured after the request. This is a JPEG snapshot interface, not a continuous video stream.

Contract and examples

The local OpenAPI file and central OpenAPI file live under postman/specs. Keep that directory structure when importing the local spec, because it references the central fusion schema. Separate website downloads do not preserve relative reference paths. The Postman guide explains collection variables and saved request examples.