Camera API

Xedge32 features the ESP32 Camera Driver and a Lua interface to this driver. To use the camera API, follow these steps:

Note that the cam documentation is not yet complete!!!

Create a camera object by invoking esp32.cam, passing a configuration table as an argument.
Call the cam:read method as many times as needed to fetch new images.
Once done, call the cam:close method to close the camera object and free up resources.

The API functions and methods are detailed below:

`esp32.cam(cfg)`

This function creates a camera object.

cfg: A configuration table, whose structure is detailed below.

The function returns the camera object if successful. If the creation of the camera object fails, it returns nil, error message.

The camera object provides the following methods:

`cam:read()`

This method is used to fetch a new image from the camera.

`cam:close()`

This method closes the camera object, freeing up any resources it was using.

The Configuration Table

The argument accepted by esp32.cam is a Lua table that maps various parameters to specific GPIO pins on the ESP32 board. These settings are used to initialize the camera module on the ESP32-CAM board.

Required parameters:

d0 to d7: These are the GPIO pins that the camera module’s pixel data lines (D0-D7) are connected to. The camera module sends digital pixel data to the ESP32 through these lines.
xclk: This is the GPIO pin that the camera clock (XCLK) is connected to.
pclk: This is the GPIO pin that the pixel clock (PCLK) is connected to.
vsync: This is the GPIO pin that the vertical sync (VSYNC) is connected to.
href: This is the GPIO pin that the horizontal reference (HREF) is connected to.
sda: This is the GPIO pin that the SCCB Data (SIOD) is connected to.
scl: This is the GPIO pin that the SCCB Clock (SIOC) is connected to.
reset: This is the GPIO pin that the camera reset line is connected to. Using this pin, you can perform a hardware reset of the camera.
freq: This sets the frequency of the XCLK signal to the camera module. It’s typically set to a value between 10 MHz and 20 MHz. Lower frequencies might be more stable, but could lead to lower frame rates.

Optional parameters:

pwdn: This is the GPIO pin that the Power Down (PWDN) line is connected to.
frame: This defines the resolution of the camera. “HD” stands for High Definition, which is typically 1280x720 pixels. This is not related to a GPIO pin but rather a configuration setting for the camera.
format: This sets the pixel format for the camera. Typical values include “RGB565”, “YUV422”, “GRAYSCALE”, or “JPEG”. The exact formats supported can depend on the specific camera module used.
vflip: If set to true, this setting flips the image vertically. This can be useful if the camera is physically installed upside down.
hmirror: If set to true, this setting mirrors the image horizontally. This can be useful if the camera image needs to be mirrored for some reason.

Configuration Table Examples:

-- Settings for Seeed Studio XIAO ESP32S3 Sense
local cfg={
   d0=15, d1=17, d2=18, d3=16, d4=14, d5=12, d6=11, d7=48,
   xclk=10, pclk=13, vsync=38, href=47, sda=40, scl=39, pwdn=-1,
   reset=-1, freq="20000000", frame="HD"
}

-- Settings for Aideepen ESP32-CAM
local cfg={
   d0=5, d1=18, d2=19, d3=21, d4=36, d5=39, d6=34, d7=35,
   xclk=0, pclk=22, vsync=25, href=23, sda=26, scl=27, pwdn=32,
   reset=-1, freq="20000000", frame="HD"
}

-- Settings for FREENOVE  ESP32-S3 WROOM
local cfg={
   d0=11, d1=9, d2=8, d3=10, d4=12, d5=18, d6=17, d7=16,
   xclk=15, pclk=13, vsync=6, href=7, sda=4, scl=5, pwdn=-1,
   reset=-1, freq="20000000", frame="HD"
}