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linefollower_eye

ESP32-S3 camera board that finds a coloured blob and reports its position over I2C. Meant to sit on a robot as the “eye”, with something like a Pico as the master.

What it does

The ESP runs HSV blob detection on the camera. A MicroPython master can turn the camera on, set colour, and poll for a target. Optionally it can join Wi‑Fi so you can open a browser page to tune the colour live.

Target position from read_target() is relative to the image centre (320x240). Positive x is right, positive y is up. Diameter is the blob size in pixels (2 × detector radius). No target returns None.

Hardware

ESP pins for the I2C slave:

SDA: GPIO19
SCL: GPIO20
Address: 0x42

Example Pico wiring:

GP0 (SDA) -> ESP GPIO19
GP1 (SCL) -> ESP GPIO20
GND shared
Use external pull-ups on SDA/SCL (about 2k2–4k7 to 3V3)

Camera and Wi‑Fi stay off until the master enables them.

Firmware

ESP-IDF project for ESP32-S3. Build and flash as usual:

idf.py build
idf.py -p PORT flash monitor

MicroPython master

Files live in mp_i2c_master/. Copy vision.py (and main.py if you want the demo) onto the board.

from vision import Vision
import time

eye = Vision(sda=0, scl=1)
eye.start() # start the camera and blob algorithm

eye.set_hsv(4, 128, 116) # Set target colour (HSV)
eye.set_rgb(255, 255, 255) # Set RGB LED to max white

# Optional: browser UI for tuning colour  
#eye.set_wifi("rr workshop", "ourpassword")
#print(eye.wifi_ip())
        
while True:
    target = eye.read_target()
    if target is None:
        print("no target")
    else:
        x, y, diameter = target
        print("target at ({}, {}) diameter={}".format(x, y, diameter))
    time.sleep(0.07)

Useful calls:

eye.start() — camera on and local detection
eye.set_hsv(h, s, v) / eye.set_tolerance(...) — colour (or tune in the browser)
eye.set_wifi(ssid, password) / eye.wifi_off() / eye.wifi_ip()
eye.read_target() — (x, y, diameter) or None
eye.set_rgb(r, g, b)
eye.set_size_limits(max_diameter=..., max_area=...) — optional; default is no max size

Web UI

After Wi‑Fi is up, open the ESP’s IP in a browser. You get the live image, colour picker / eyedropper, mask options, and timing. Colour changes there are what the I2C master reads next.

Other folders

pc_vision/ — older desktop viewer; the on-device web UI replaces it for tuning
main/ — ESP firmware

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