Switching power to a sim800L (npn didn't work efficiently )

Other Hardware General Electronics
1

Hi to all
i have one sim800L module that i want to switch on/off the power from an arduino (Pro mini 3.3v - 8MHz) .
the sim800L needs 3.4v - 4.4 volt dc

i am using a 18650 battery back that delivers 3.7 volt
when i am connecting the battery directly to the module , works fine

i tried to use simple npn transistors (NPN 3904, 2N2222, bc547c) and a darlington transistor (tip120) but was not able to make the module work .

i have a drop of voltage about 0.5v (3.2 volt on the module through the npn) so the module cant connect to the cellular network (very common problem when it has not enough power)

are any other solutions to suggest me in order to open and close the power of this module through the arduino ?

Thanks in advance

2

The transistors mentioned can't switch the current draw (~2Amp) when the module is transmitting.
Switching power or ground is also destructive for the module's data pins if you do it wrong.

This question comes up more often, and you should be able to find the answers with a site search.
No practical experience there, but I read that the module can be put to sleep with AT commands.
Leo..

3

Thanks for the interesting

yes i know about the At command putting the module to sleep mode (i have implement this to my code)

just wanted to experiment with the option can powering off the module