Problem with SIM800L GSM module and servo I have a SIM800L GSM module like in this link, .

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The problem is when I connect the GSM to my Arduino Uno the GSM turns on for a while and then turns off. I tried to connect it with a 9-volt battery and an LM7805 voltage regulator, but I have the same problem. Attached to the Arduino are an LM35 temperature sensor, two LEDs, a buzzer, an LCD, a GSM module, a gas sensor and a servo.

The other problem is with the servo. I tested the servo and it works fine but when the servo stops moving, it starts to shake. I do not know what the problem is.
You SIM800 module will pull 2Amps when its transmitting.  If your servo is also trying to overcome the inertia at the start of a movement it will pull 4+ times its normal running current.

A 9 volt battery will let you pull a couple of hundred milliamps.  So when the GSM transmits you system will shutdown.

You need a proper power supply or a battery pack that can put out these levels of peak current (3+Amps)