README.md

Notes for ESP32

• ESP32 does only have serial ports 0-2 (where UART0 is used for stdout by default)
• You can run idf targets like menuconfig or monitor by specifing the target as an argument to the build_firmware.sh script
• The GPIO pins for the configured serial port can be set with menuconfig (see micro-ROS Transport Settings menu)
• ESP32 only runs in singlecore mode (CONFIG_FREERTOS_UNICORE=y setting)

Notes for ESP32-CAMERA

• SPIRAM is requierd only for ESP32-CAMERA and can cause a fatal error in ESP32 (Enable in menuconfig Component config > ESP32-specific OR add CONFIG_ESP32_SPIRAM_SUPPORT=y to sdkconfig.defaults file).
• Make sure that rtc_gpio_desc array is supported in menuconfig: Component config > Driver configurations > RTCIO configuration (set to TRUE) OR write this line CONFIG_RTCIO_SUPPORT_RTC_GPIO_DESC=y to sdk.defaults.
• Choose your camera pins configuration in menuconfig Camera configuration > Camera pins. (BOARD_ESP32CAM_AITHINKER is default).
• In order to view the images you will need to create a cv_bridge:

#!/usr/bin/env python3
import rclpy
from rclpy.node import Node
from std_msgs.msg import String
from cv_bridge import CvBridge, CvBridgeError
from sensor_msgs.msg import CompressedImage
import cv2
import numpy as np




class MinimalSubscriber(Node):

    def __init__(self, ):
        super().__init__('minimal_subscriber')
        self.subscription = self.create_subscription(CompressedImage, 'freertos_picture_publisher', self.listener_callback, 10)
        self.subscription  # prevent unused variable warning 
        self.bridge = CvBridge()
    def listener_callback(self, image_message):
        self.get_logger().info('recieved an image')
        
    	#recieve image and co nvert to cv2 image
        cv2.imshow('esp32_image', self.cv_image)
        cv2.waitKey(3)

        


def main(args=None):
    rclpy.init(args=args)
    minimal_subscriber = MinimalSubscriber()
    
    rclpy.spin(minimal_subscriber)
    minimal_subscriber.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
   main()