Send SMS using microcontroller
Today I want introduce a very nice GSM module that enabling you send/receive text message and voice call. this module also can connect to GPRS.
if you want send sms using microcontroller in your project, you have many choices but this module is cheap, stable & power efficient. This module can easily connect to microcontroller using 2 wires. this module called SIM900.
Sim900 is a GSM/GPRS module. This module designed for global market and can works in GSM 850/900/1800 and 1900 MHz. this tiny module support GPRS multi-slot class 10 & class 8.
module size is very tiny ( 24*24*3 mm ) this size enable circuit designers to use this module in portable and tiny devices. some people make secret surveillance with this module 😀 you can use this module in wide range of projects. this module can be stable for month to years if you design professional PCB.
SIM900 is SMD module that has 68 SMT pads. WOW ! don’t worry you will not need all of pins. this module has too much features enable you make a cellphone! but you want control this module with a microcontroller.
energy consumption of this module is as low as 1 mA in stand by mode but when this module registering in network is high as 2 Amps for a very short moment. this module energy consumption is low but you should consider 2 A peak current in circuit design. you can solve this problem by DC/DC converter ICs like LM2576/LM2596 and large capacitors on power ( +1000uF ).
This module works with 3.2 V to 4.8 V power supply & working temperature is -30 ~ +80 °C.
After you connect this module to microcontrollers you can control module with AT Commands.
You can Download 2 files below as sim900 datasheet.
one file is Hardware design guide, this file help you design a very stable circuit and other file is AT commands this file help you know about commands and learn how to use commands for make call, answer call, send text message, read messages, run USSD code, check network quality & etc.
Download Sim900 Datasheet:
Hardware Design Guide