Hello everyone,
I have a spesific problem about Arduino - Sim900 GSM module connection. In my opinion its not about the code.
I can send-recieve data, sms and make phone call. But there is a limitation that i have.
I connect the SIM900 shield via wires and commucinate the module with AT commands. I also plug a 12V 1.5A adaptor to the card for power requirements.
When I attach USB cable, i can read the realtime values from serial monitor and everything works fine.
But if i detach the USB cable it doesn't send data to the server.
Im using the lastest version of arduino IDE 1.8.5. But I think its not about the program. Its about the USB cable. If i plug the USB cable to pc with adapter it is working well. Otherwise its not working.
What is the importance of the USB cable ? Was one of the component broken?
Thanks for your replies ...