@martinnn lib_imu is a library that I wrote and in this function give only data from IMU and there aren't any delay. if I wrote data immediately on a file.txt in SD card it employ 0,2 s so the sample became 0,4. but if I collect data and insert them in a list to save data at the end of acquisition it gives me the error 'Memory allocation'.

@bmarkus said in How to transmit every 30-60 seconds data from LoPy: @rcolistete said in How to transmit every 30-60 seconds data from LoPy: LoRa or LoRaWan ? Regulations are the same for all devices independtly they are LoRa, LoRaWAN or other ISM devices. To know the packet size = payload + LoRaWan header/etc (typically 13 bytes).