SIM800l do not connect to network


Hello. I’m trying to make a project with my Arduino and a SIM800L module (The red one with the spring like antenna). I activated my SIM card and tried it in my smartphone (and it’s working). The problem is that i cannot call the SIM card once i put him in the SIM800l. I’m supplying the module with a 4.5V/3A power supply but the red LED blinks 3 times and then stops for 30 seconds and blinks again 3 times. Any ideas of what can be the problem?
Thank you!


Hello, verify of frequency operation is compatible whith your module? of which country are you from?


Why are you giving 4.5V. It s out of its max rating. Maximum voltage is 4.2V . Anything above will put module into overvoltage power down.


Hello, I’m from Portugal


I read that on the Datasheet of the module but i saw some projects on the internet that used the 5V from Arduino they work properly. I’ll buy a voltage regulator and try with it.


If you have a 5V with 2A capable source, get a low drop out high current regulator like LM39302 . It should work.


Which is the max dropout voltage of the LM39302? 0.5V right? If that’s the max, the output of the LM39302 and the output of my power supply will be the same (4.5V)


Thats minimum dropout voltage. Not regulated voltage. The output voltage is adjustable with resistors. :slight_smile:


Thank you for your help!! My project is already working. I bought a lm2596 dc-dc voltage regulator, and it’s working perfectly. Thank you again!


Thats great :slight_smile: