Hello! I use 12V, 2A external power supply for arduino. +5V from arduino powers the LCD and a 6V buzzer. I also have a servo motor connected to digital pin 5 of and powers it from another external source which is 6V, 500mA. Of course both GND of servo and arduino are connected.
I'd like to power the sms module using the source from the arduino. Can I just use the Vin and GND pins to connect it to the gms module? I just measured the voltage from the Vin pin and instead of getting 12V I only get 11.40V.
I also noticed that the capacitors slowly get hot after a few minutes! Is it okay?