Hello! I’d like to know if it’s possible to have three ESP32-CAM modules communicate with each other as follows:
Main Camera: Sends a command to the other two cameras to take a picture.
Secondary and Third Cameras: Receive the command, capture an image, and send the photo back to the Main Camera.
Main Camera: Saves all three images (its own and the two received) to the SD card and displays them on a web browser.
I already have the code for the Main Camera to capture a photo, save it to the SD card, and show it on a web interface. However, I’m unsure how to implement the image transfer between ESP32-CAMs, especially since I read that ESP-NOW has a packet size limit of 250 bytes.
You need to split the image into a series of segments or packets say 250 bytes long, then transmit each segment in turn which the receiver accepts and sends an acknowledge back to the transmitter so no segments are missed. You also need to be able to detect when segments are received out of sequence, the receiver for instance could receive segment, send an ack but the transmitter does not receive the ack.
The receiver receives each segment in turn and saves them, in the correct sequence to a PSRAM array (or SD file) which when all the segments have been sent becomes the complete image.
The reason for the send and acknowledge is simple, RF comms is never 100% reliable, so you need to be able to deal with segments not received or received with errors.
This transfer process has been done with LoRa, packet size limit 255 bytes, so the same ought to be possible with ESPNOW.