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Twice per second: connected through GPRS.Every three seconds: connected to a network.The frequency of the blinking means something: If there's not enough power, the LED blinks for about three seconds, then turns off. If the power to the SIM800L is enough, the on-board LED starts blinking. My network test project uses a battery to supply power to the SIM800L. I recommend Li-Po battery with higher ampere-hour ratings so that it can provide the SIM800L's current requirements. Take note that the input voltage must be at least 1.5 V higher than the output.Ī Li-Po battery works well too, since they provide 3.7 V. You simply use a higher voltage in its input then adjust the on-board potentiometer to have 3.7 to 4.4 V for the SIM800L. The LM2596S can provide a maximum 3 A to its load.
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If selecting a voltage regulator, I recommend the LM2596S regulator module. The better approach is either to use a regulator or just have the SIM800L draw from a Li-Po battery. Maybe this would solve the voltage problem, but not the current problem. Some also use a diode to drop the 5 V voltage to ~4.3 V (assuming a silicon diode). they are very close to mobile network transmitters, which means the SIM800L doesn't need to draw too much power to establish a connection.their Arduino's have internal regulators that drop the voltage to ~4.4-4.5 V when the SIM800L is connected.However, these might explain why their modules work: When on USB port, the Arduino's 5V pin can supply a maximum of 450 mA and when on its DC Jack, about 800 mA. Some YouTube videos power their modules from the Arduino UNO's power pins which really doesn't work for me. However, its TX and RX pins are 5V tolerant. This means you must not connect its pins directly to a 5 V Arduino! It doesn't even run on 3.3 V. This board draws a maximum of 2 A with an input voltage of 3.7 V to 4.2 V. Power requirements is probably the most common issue with the SIM800L. Go to SIM900 Tutorial if you have that module instead Powering the Board