SIM800L GSM Module Connections (Requires Level Shifting) The SIM800L module needs special attention because it operates at 3.3V logic levels while Arduino uses 5V. We need a voltage divider circuit to ...

Hardware To start, set up the hardware as shown below. Naturally, you’re going to need a valid SIM card to fully use the SIM800L module. For compactness, my setup was tested with a 1S (3.7-V) Li-ion ...

When we send SMS to GSM module by Mobile, then GSM receives that SMS and sends it to Arduino. Now Arduino reads this SMS and extract main command from the received string and stores in a variable.