a have a Arduino pro mini (compatible) Board connected to a SIM800c module via Pin2/3 by using Software Serial. After some huddles with String-Variables the project works now perfectly when arduino is connected via USB to my PC an (normal) 5V Circuit is power on tool (because SIM800c needs more Power for sending)
But when i disconnect USB from PC the Serial Connection to SIM800C doesnt work work well. Unfortunally - i'm a little bit blind without Serial prints.
Anybody can help me? can it be an electrical problem (Add Info: connect the USB to a powerbank doesnt work too)
Almost certainly, and a dire shortage of watts springs readily to mind. The exact problem is far from clear and probably depends on what you mean by
doesnt work work well.
You seem to imply that the USB port is your salvation, whereas I would have thought that, as far as power is concerned, the opposite would have been more likely.
I don't understand why these things hog so much power, but I do understand you need a decent power supply with 5v 3A, one for Nano and two for the phone. I don't understand why you want to disconnect USB anyway. It seems self-defeating, but I'm sure you shouldn't rely on it for power.
you're right - but unfortunally when i use Board "Ardunio Nano" in IDE i cant upload my sketch. there are errors like
"avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xac
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0xac
avrdude: stk500_recv(): programmer is not responding"