insecam desk widget (LilyGO T-Embed)

A little window onto the world's public webcams. The T-Embed's 320×170 IPS screen shows a random camera from insecam.org — as live MJPEG video where the camera streams it — and moves on to the next one every 20 seconds. The knob steps through cameras, the LED ring drains as the countdown runs. Everything happens on the ESP32-S3; no bridge or PC needed.

insecam lists cameras that are reachable on the public internet without any password. The widget only ever does what a browser on that site does: fetch a listing page, then fetch the camera's own snapshot/stream URL.

Hardware

Either LilyGO T-Embed. The firmware tells them apart at boot by probing the I2C bus (ES7210 on the 2022 board, BQ27220/BQ25896/PN532 on the CC1101 board) and picks the matching pin map from main/board.c. Nothing beyond the board is needed: ESP32-S3R8, 16 MB flash, 8 MB PSRAM, ST7789 170×320, EC11 encoder, APA102 (×7) or WS2812 (×8) ring.

Build and flash

Needs ESP-IDF 5.5 (on this machine: . ~/esp/idf55-env.sh).

idf.py set-target esp32s3
idf.py build
idf.py -p /dev/ttyACM0 flash monitor

The partition table keeps nvs where the ESPHome build that shipped on this unit had it (0xf90000), so stored Wi-Fi credentials survive re-flashing. Options (interval, listing, brightness, forced variant) live under idf.py menuconfig → insecam desk widget.

First boot / Wi-Fi

With no saved network the widget opens the open hotspot insecam-setup; join it with a phone and the captive portal (or http://192.168.4.1) asks for your Wi-Fi. Holding the knob down while the widget starts forces the portal.

Controls

input	action
turn clockwise	next camera
turn counter-clockwise	previous camera (history of 24)
click	pause / resume the countdown (the live stream keeps playing)
double-click or hold	hide / show the caption

How it works

• insecam.c fetches one listing page (/en/byrating/ or /en/bynew/, random page) — six cameras per request, so insecam sees one hit every two minutes.
• httpstream.c is a small raw-socket HTTP client: esp_http_client gives up on bodies without Content-Length, which is exactly what MJPEG cameras send.
• jpegframe.c pulls complete JPEG files out of the byte stream by walking the marker structure (so an EXIF thumbnail's EOI can't truncate a frame).
• jpegdec.c decodes with Espressif's esp_new_jpeg, scaling inside the decoder to the smallest multiple-of-8 size that still covers the screen, then bilinear-resamples the remainder to a full-bleed 320×170 (≈100 ms for a 1280×800 frame, so MJPEG streams play at a few fps).
• slideshow.c runs the state machine: connect, play frames until the interval elapses or the knob moves, skip dead cameras, keep history for "previous".
• ui.c is LVGL 9 via esp_lvgl_port: a canvas for the frame, a translucent caption bar, a LIVE/PAUSED badge and a hairline progress bar.