I'm having trouble again with the "PLEASE INSERT A SD CARD" message. The curious one that already used the Ferduino usually for more than a month without appearing any problem.
My Ferduino has the Arduino Mega board 2560 + Arduino Shield + TFT indicated + TFT shield Mega Shield V2.2 + ESP8266 + 5 level sensors + 3 temperature sensors + buzzer + RTC DS3231; and all this worked normally.
I use a 9V source, but I have tried other sources with voltages between 5V to 12V and the same problem continues.
Interestingly there are moments that the Ferduino normally enters without appearing the message, and others appear the message, what can be happening?