I am trying to test a cheap (~10$) SIM800L GSM\GPRS module with Arduino mega.
This is the module: http://www.aliexpress.com/item/Quad-Band-Quad-Band-SIM800L-GPRS-Module-Bomb-Slot-Automatic-MicroSIM-Card-FZ1036/1992534325.html?spm=2114.03101022.214.171.124AdN6k&ws_ab_test=searchweb201556_1_21_79_78_77_92_91_22_80,searchweb201644_5,searchweb201560_9
Wiring: I connected a 4v (up tp 1.2A) power source to the module Vcc pin (using dc to dc converter). The TX pin from the sim module go (directly) to the RX serial2 (hardware serial2 on the mega board) pin on the Arduino and the RX sim pin go to the TX Arduino pin.
I uploaded a sketch that will direct Serial data to Serial2 and vice versa.
The problem is that i am sending "AT" command (simply by typing 'AT' in the Arduino IDE terminal with both NL & CR option checked, and press enter) and i am getting no respond from the module....
I also tried to use the software serial but with no luck... the module have a green led that flashing rapidly
anyone have experience with that module? any help will be grateful