A bare bones, no thrills simple sketch to verify if your camera is working without the need for WiFi or displays. This example is aimed at the AI-Thinker type of ESP32-CAM dev board fitted with PSRAM.
The program initialises the camera, then takes a photo, transfers the full frame data to the PSRAM and reports the frame time and RGB values of the centre pixel to the serial monitor. You can then move the camera from light to dark to see the values change.
Please note that the frame size is set to 240x240pixels, and as the output comes from a 16-bit RGB sensor value, the maximum values for the red and blue channel are limited to 31 (5 bits = 25-1), and 63 (6 bits = 26-1) for green.
Software – Code
#include "esp_camera.h"
#include <SPI.h>
#define CAMERA_MODEL_AI_THINKER
#define PWDN_GPIO_NUM 32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 0
#define SIOD_GPIO_NUM 26
#define SIOC_GPIO_NUM 27
#define Y9_GPIO_NUM 35
#define Y8_GPIO_NUM 34
#define Y7_GPIO_NUM 39
#define Y6_GPIO_NUM 36
#define Y5_GPIO_NUM 21
#define Y4_GPIO_NUM 19
#define Y3_GPIO_NUM 18
#define Y2_GPIO_NUM 5
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22
camera_config_t config;
int n_elements = 57600;
long initalTime = 0;
long frameTime;
void setup() {
psramInit();
config.ledc_channel = LEDC_CHANNEL_0;
config.ledc_timer = LEDC_TIMER_0;
config.pin_d0 = Y2_GPIO_NUM;
config.pin_d1 = Y3_GPIO_NUM;
config.pin_d2 = Y4_GPIO_NUM;
config.pin_d3 = Y5_GPIO_NUM;
config.pin_d4 = Y6_GPIO_NUM;
config.pin_d5 = Y7_GPIO_NUM;
config.pin_d6 = Y8_GPIO_NUM;
config.pin_d7 = Y9_GPIO_NUM;
config.pin_xclk = XCLK_GPIO_NUM;
config.pin_pclk = PCLK_GPIO_NUM;
config.pin_vsync = VSYNC_GPIO_NUM;
config.pin_href = HREF_GPIO_NUM;
config.pin_sscb_sda = SIOD_GPIO_NUM;
config.pin_sscb_scl = SIOC_GPIO_NUM;
config.pin_pwdn = PWDN_GPIO_NUM;
config.pin_reset = RESET_GPIO_NUM;
config.xclk_freq_hz = 20000000;
config.frame_size = FRAMESIZE_240X240;
config.pixel_format = PIXFORMAT_RGB565;
config.grab_mode = CAMERA_GRAB_LATEST;
config.fb_location = CAMERA_FB_IN_PSRAM;
config.jpeg_quality = 12;
config.fb_count = 2;
esp_err_t err = esp_camera_init(&config);
sensor_t * s = esp_camera_sensor_get();
s->set_brightness(s, 0); // -2 to 2
s->set_contrast(s, 0); // -2 to 2
s->set_saturation(s, 0); // -2 to 2
s->set_special_effect(s, 0); // 0 to 6 (0 - No Effect, 1 - Negative, 2 - Grayscale, 3 - Red Tint, 4 - Green Tint, 5 - Blue Tint, 6 - Sepia)
s->set_whitebal(s, 1); // 0 = disable , 1 = enable
s->set_awb_gain(s, 1); // 0 = disable , 1 = enable
s->set_wb_mode(s, 0); // 0 to 4 - if awb_gain enabled (0 - Auto, 1 - Sunny, 2 - Cloudy, 3 - Office, 4 - Home)
s->set_exposure_ctrl(s, 1); // 0 = disable , 1 = enable
s->set_aec2(s, 0); // 0 = disable , 1 = enable
s->set_ae_level(s, 0); // -2 to 2
s->set_aec_value(s, 300); // 0 to 1200
s->set_gain_ctrl(s, 1); // 0 = disable , 1 = enable
s->set_agc_gain(s, 0); // 0 to 30
s->set_gainceiling(s, (gainceiling_t)0); // 0 to 6
s->set_bpc(s, 0); // 0 = disable , 1 = enable
s->set_wpc(s, 1); // 0 = disable , 1 = enable
s->set_raw_gma(s, 1); // 0 = disable , 1 = enable
s->set_lenc(s, 1); // 0 = disable , 1 = enable
s->set_hmirror(s, 0); // 0 = disable , 1 = enable
s->set_vflip(s, 0); // 0 = disable , 1 = enable
s->set_dcw(s, 1); // 0 = disable , 1 = enable
s->set_colorbar(s, 0); // 0 = disable , 1 = enable
Serial.begin(115200);
delay(1000);
}
void loop() {
initalTime = millis();
//allocate space on PSRAM - can be done in setup(), but doesn't save any time
uint16_t *frame_buffer = (uint16_t *) ps_malloc(n_elements * sizeof(uint16_t));
//take picture
camera_fb_t * fb = NULL;
fb = esp_camera_fb_get();
//Transfer camera buffer to buffer in PSRAM
for (int i = 0; i < 57600; i++) { //240x240px = 57600
//create 16 bit colour from two bytes.
byte first_byte = fb->buf[i * 2];
byte second_byte = fb->buf[i * 2 + 1];
frame_buffer[i] = (first_byte << 8) + second_byte;
}
//analyse centre pixel (number 28800 of 57600), and report colour values
uint16_t R = (0b1111100000000000 & frame_buffer[28800]) >> 11;
uint16_t G = (0b1111110000000000 & (frame_buffer[28800] << 5)) >> 10;
uint16_t B = (0b1111100000000000 & (frame_buffer[28800] << 11)) >> 11;
esp_camera_fb_return(fb); //return the frame buffer back to the driver for reuse
free(frame_buffer); //free up section of PSRAM
frameTime = millis() - initalTime;
Serial.println("Centre pixel colour:");
Serial.print("R: "); Serial.println(R);
Serial.print("G: "); Serial.println(G);
Serial.print("B: "); Serial.println(B);
Serial.print("Image process time(ms): ");
Serial.println(frameTime);
}Best of luck!!
Page created: 19/03/2026
Last updated: 19/03/2026