Question/Issue:
[Describe the question or issue in detail]
Project ID:
606450
Context/Use case:
I am working on an IoT project using an ESP32-CAM with Edge Impulse for image recognition. When a plastic bottle is detected, I want to send a message from the ESP32-CAM to another ESP32 board using UART. However, I am unsure of the best approach to implement this.
Steps Taken:
TAKE NOTE: I’m not using the built in TX and RX because it is used the by FTDI module also I tested the connection first with the basic connection test and it did work
- Configured
HardwareSerial mySerial(1);with TX on GPIO 14 and RX on GPIO 15. - Used
mySerial.write('1');to send data when a plastic bottle is detected. - On the receiving ESP32, initialized
Serial2.begin(9600, SERIAL_8N1, RX_PIN, TX_PIN);to read incoming data.
Expected Outcome:
The receiving ESP32 should detect and process the message when a plastic bottle is identified.
Actual Outcome:
No data is being received on the second ESP32. I tried different baud rates and GPIO pins but still cannot establish communication.
Reproducibility:
- [ ] Always
Environment:
- Platform: ESP32-CAM (AI Thinker) & ESP32
- Build Environment Details: Arduino IDE 2.0.4 ESP32 Core for Arduino
- OS Version: Windows 11
Additional Information:
// These sketches are tested with 2.0.4 ESP32 Arduino Core
// Release ESP32 Arduino 2.0.4 based on ESP-IDF 4.4.1 · espressif/arduino-esp32 · GitHub
/* Includes ---------------------------------------------------------------- */
#include <EcoPoints_-_Image_Recognition_inferencing.h>
#include “edge-impulse-sdk/dsp/image/image.hpp”
#include “esp_camera.h”
#include “HardwareSerial.h”
// Select camera model - find more camera models in camera_pins.h file here
// arduino-esp32/libraries/ESP32/examples/Camera/CameraWebServer/camera_pins.h at master · espressif/arduino-esp32 · GitHub
//#define CAMERA_MODEL_ESP_EYE // Has PSRAM
#define CAMERA_MODEL_AI_THINKER // Has PSRAM
// UART settings
#define TX_PIN 14
#define RX_PIN 15
HardwareSerial mySerial(1); // Use UART 1
#if defined(CAMERA_MODEL_ESP_EYE)
#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 4
#define SIOD_GPIO_NUM 18
#define SIOC_GPIO_NUM 23
#define Y9_GPIO_NUM 36
#define Y8_GPIO_NUM 37
#define Y7_GPIO_NUM 38
#define Y6_GPIO_NUM 39
#define Y5_GPIO_NUM 35
#define Y4_GPIO_NUM 14
#define Y3_GPIO_NUM 13
#define Y2_GPIO_NUM 34
#define VSYNC_GPIO_NUM 5
#define HREF_GPIO_NUM 27
#define PCLK_GPIO_NUM 25
#elif defined(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
#else
#error “Camera model not selected”
#endif
/* Constant defines -------------------------------------------------------- */
#define EI_CAMERA_RAW_FRAME_BUFFER_COLS 320
#define EI_CAMERA_RAW_FRAME_BUFFER_ROWS 240
#define EI_CAMERA_FRAME_BYTE_SIZE 3
/* Private variables ------------------------------------------------------- */
static bool debug_nn = false; // Set this to true to see e.g. features generated from the raw signal
static bool is_initialised = false;
uint8_t *snapshot_buf; //points to the output of the capture
static camera_config_t camera_config = {
.pin_pwdn = PWDN_GPIO_NUM,
.pin_reset = RESET_GPIO_NUM,
.pin_xclk = XCLK_GPIO_NUM,
.pin_sscb_sda = SIOD_GPIO_NUM,
.pin_sscb_scl = SIOC_GPIO_NUM,
.pin_d7 = Y9_GPIO_NUM,
.pin_d6 = Y8_GPIO_NUM,
.pin_d5 = Y7_GPIO_NUM,
.pin_d4 = Y6_GPIO_NUM,
.pin_d3 = Y5_GPIO_NUM,
.pin_d2 = Y4_GPIO_NUM,
.pin_d1 = Y3_GPIO_NUM,
.pin_d0 = Y2_GPIO_NUM,
.pin_vsync = VSYNC_GPIO_NUM,
.pin_href = HREF_GPIO_NUM,
.pin_pclk = PCLK_GPIO_NUM,
//XCLK 20MHz or 10MHz for OV2640 double FPS (Experimental)
.xclk_freq_hz = 20000000,
.ledc_timer = LEDC_TIMER_0,
.ledc_channel = LEDC_CHANNEL_0,
.pixel_format = PIXFORMAT_JPEG, //YUV422,GRAYSCALE,RGB565,JPEG
.frame_size = FRAMESIZE_QVGA, //QQVGA-UXGA Do not use sizes above QVGA when not JPEG
.jpeg_quality = 12, //0-63 lower number means higher quality
.fb_count = 1, //if more than one, i2s runs in continuous mode. Use only with JPEG
.fb_location = CAMERA_FB_IN_PSRAM,
.grab_mode = CAMERA_GRAB_WHEN_EMPTY,
};
/* Function definitions ------------------------------------------------------- */
bool ei_camera_init(void);
void ei_camera_deinit(void);
bool ei_camera_capture(uint32_t img_width, uint32_t img_height, uint8_t *out_buf) ;
/**
-
Arduino setup function
*/
void setup()
{
Serial.begin(115200);
mySerial.begin(9600, SERIAL_8N1, RX_PIN, TX_PIN); // Initialize UART
//while (!Serial);
Serial.println("Edge Impulse Inferencing Demo");
if (ei_camera_init() == false) {
ei_printf("Failed to initialize Camera!\r\n");
}
else {
ei_printf("Camera initialized\r\n");
}
ei_printf("\nStarting continious inference in 2 seconds...\n");
ei_sleep(2000);
}
/**
-
Get data and run inferencing -
param[in] debug Get debug info if true
*/
void loop()
{
if (ei_sleep(5000) != EI_IMPULSE_OK) {
return;
}snapshot_buf = (uint8_t*)malloc(EI_CAMERA_RAW_FRAME_BUFFER_COLS * EI_CAMERA_RAW_FRAME_BUFFER_ROWS * EI_CAMERA_FRAME_BYTE_SIZE);
// check if allocation was successful
if(snapshot_buf == nullptr) {
ei_printf(“ERR: Failed to allocate snapshot buffer!\n”);
return;
}ei::signal_t signal;
signal.total_length = EI_CLASSIFIER_INPUT_WIDTH * EI_CLASSIFIER_INPUT_HEIGHT;
signal.get_data = &ei_camera_get_data;if (ei_camera_capture((size_t)EI_CLASSIFIER_INPUT_WIDTH, (size_t)EI_CLASSIFIER_INPUT_HEIGHT, snapshot_buf) == false) {
ei_printf(“Failed to capture image\r\n”);
free(snapshot_buf);
return;
}ei_impulse_result_t result = {0};
EI_IMPULSE_ERROR err = run_classifier(&signal, &result, debug_nn);if (err == EI_IMPULSE_OK) {
//ei_printf(“Inference ran successfully.\n”);
for (uint32_t i = 0; i < result.bounding_boxes_count; i++) {
ei_impulse_result_bounding_box_t bb = result.bounding_boxes[i];
// ei_printf(“Label: %s, Confidence: %f\n”, bb.label, bb.value);// Check if the detected object is a plastic bottle if (strcmp(bb.label, "plasticBottle") == 0 && bb.value > 0.5) { ei_printf("Plastic bottle detected!\n"); mySerial.write('1'); // Send a message "1" to ESP32 } }} else {
ei_printf(“Error running classifier: %d\n”, err);
}// print the predictions
ei_printf(“Predictions (DSP: %d ms., Classification: %d ms., Anomaly: %d ms.): \n”,
result.timing.dsp, result.timing.classification, result.timing.anomaly);
#if EI_CLASSIFIER_OBJECT_DETECTION == 1
ei_printf(“Object detection bounding boxes:\r\n”);
for (uint32_t i = 0; i < result.bounding_boxes_count; i++) {
ei_impulse_result_bounding_box_t bb = result.bounding_boxes[i];
if (bb.value == 0) {
continue;
}
ei_printf(" %s (%f) [ x: %u, y: %u, width: %u, height: %u ]\r\n",
bb.label,
bb.value,
bb.x,
bb.y,
bb.width,
bb.height);
}
#else
ei_printf(“Predictions:\r\n”);
for (uint16_t i = 0; i < EI_CLASSIFIER_LABEL_COUNT; i++) {
ei_printf(" %s: “, ei_classifier_inferencing_categories[i]);
ei_printf(”%.5f\r\n", result.classification[i].value);
}
#endif
#if EI_CLASSIFIER_HAS_ANOMALY
ei_printf(“Anomaly prediction: %.3f\r\n”, result.anomaly);
#endif
#if EI_CLASSIFIER_HAS_VISUAL_ANOMALY
ei_printf(“Visual anomalies:\r\n”);
for (uint32_t i = 0; i < result.visual_ad_count; i++) {
ei_impulse_result_bounding_box_t bb = result.visual_ad_grid_cells[i];
if (bb.value == 0) {
continue;
}
ei_printf(" %s (%f) [ x: %u, y: %u, width: %u, height: %u ]\r\n",
bb.label,
bb.value,
bb.x,
bb.y,
bb.width,
bb.height);
}
#endif
free(snapshot_buf);
}
/**
-
brief Setup image sensor & start streaming
-
retval false if initialisation failed
*/
bool ei_camera_init(void) {if (is_initialised) return true;
#if defined(CAMERA_MODEL_ESP_EYE)
pinMode(13, INPUT_PULLUP);
pinMode(14, INPUT_PULLUP);
#endif
//initialize the camera
esp_err_t err = esp_camera_init(&camera_config);
if (err != ESP_OK) {
Serial.printf("Camera init failed with error 0x%x\n", err);
return false;
}
sensor_t * s = esp_camera_sensor_get();
// initial sensors are flipped vertically and colors are a bit saturated
if (s->id.PID == OV3660_PID) {
s->set_vflip(s, 1); // flip it back
s->set_brightness(s, 1); // up the brightness just a bit
s->set_saturation(s, 0); // lower the saturation
}
#if defined(CAMERA_MODEL_M5STACK_WIDE)
s->set_vflip(s, 1);
s->set_hmirror(s, 1);
#elif defined(CAMERA_MODEL_ESP_EYE)
s->set_vflip(s, 1);
s->set_hmirror(s, 1);
s->set_awb_gain(s, 1);
#endif
is_initialised = true;
return true;
}
/**
-
brief Stop streaming of sensor data
*/
void ei_camera_deinit(void) {//deinitialize the camera
esp_err_t err = esp_camera_deinit();if (err != ESP_OK)
{
ei_printf(“Camera deinit failed\n”);
return;
}is_initialised = false;
return;
}
/**
- brief Capture, rescale and crop image
- param[in] img_width width of output image
- param[in] img_height height of output image
- param[in] out_buf pointer to store output image, NULL may be used
-
if ei_camera_frame_buffer is to be used for capture and resize/cropping. - retval false if not initialised, image captured, rescaled or cropped failed
*/
bool ei_camera_capture(uint32_t img_width, uint32_t img_height, uint8_t *out_buf) {
bool do_resize = false;
if (!is_initialised) {
ei_printf("ERR: Camera is not initialized\r\n");
return false;
}
camera_fb_t *fb = esp_camera_fb_get();
if (!fb) {
ei_printf("Camera capture failed\n");
return false;
}
bool converted = fmt2rgb888(fb->buf, fb->len, PIXFORMAT_JPEG, snapshot_buf);
esp_camera_fb_return(fb);
if(!converted){
ei_printf(“Conversion failed\n”);
return false;
}
if ((img_width != EI_CAMERA_RAW_FRAME_BUFFER_COLS)
|| (img_height != EI_CAMERA_RAW_FRAME_BUFFER_ROWS)) {
do_resize = true;
}
if (do_resize) {
ei::image::processing::crop_and_interpolate_rgb888(
out_buf,
EI_CAMERA_RAW_FRAME_BUFFER_COLS,
EI_CAMERA_RAW_FRAME_BUFFER_ROWS,
out_buf,
img_width,
img_height);
}
return true;
}
static int ei_camera_get_data(size_t offset, size_t length, float *out_ptr)
{
// we already have a RGB888 buffer, so recalculate offset into pixel index
size_t pixel_ix = offset * 3;
size_t pixels_left = length;
size_t out_ptr_ix = 0;
while (pixels_left != 0) {
// Swap BGR to RGB here
// due to https://github.com/espressif/esp32-camera/issues/379
out_ptr[out_ptr_ix] = (snapshot_buf[pixel_ix + 2] << 16) + (snapshot_buf[pixel_ix + 1] << 8) + snapshot_buf[pixel_ix];
// go to the next pixel
out_ptr_ix++;
pixel_ix+=3;
pixels_left--;
}
// and done!
return 0;
}
#if !defined(EI_CLASSIFIER_SENSOR) || EI_CLASSIFIER_SENSOR != EI_CLASSIFIER_SENSOR_CAMERA
#error “Invalid model for current sensor”
#endif