Project Hub /Basic Analog & Power Electronics/Power Supplies & Voltage Regulators/In-Depth: Send Receive SMS & Call with SIM900 GSM Shield & Arduino

Intermediate

ARDUINO

Project Specific

3 – 6 Hours

Partial Kit

In-Depth: Send Receive SMS & Call with SIM900 GSM Shield & Arduino

Learn how to interface the SIM900 GSM/GPRS Shield with an Arduino to send text messages, make voice calls, and test AT commands.

Originally published on LastMinuteEngineers

View original tutorial

Parts You'll Need

This project is sourced from another site, not written by us — this list is our best match of their components against what we stock, not a verified bill of materials. Always check the original blog (linked above) for the actual parts list before buying.

Arduino UNO R3 Board (Compatible) – ATmega328P Microcontroller with USB Cable Rs. 999.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Microphone module - Analog Sound Sensor Module for Arduino Rs. 63.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: GSM / GPRS SIM800L

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How It Works

The core of this system is the Arduino Uno, which communicates with the SIM900 GSM/GPRS Shield primarily through serial communication using AT (Attention) commands. The Arduino acts as the master controller, sending textual commands such as 'AT+CMGS' to send SMS messages or 'ATD' to initiate a voice call over cellular frequencies. Because the SIM900 module requires a robust power source during network registration and transmission spikes—drawing up to 2A of current—an external 5V to 9V DC power supply is connected directly to the shield to supplement the Arduino's onboard regulator. A physical 2G full-size SIM card must be inserted into the shield's cardholder to authenticate the device on a compatible cellular network, allowing it to register and receive signals via the attached GSM antenna. Optionally, an electret microphone and earphone can be connected to the audio jacks on the shield to enable live two-way voice communication during active phone calls. The Arduino IDE is used to write and upload the control sketches that automate these processes, enabling the microcontroller to interact seamlessly with global cellular infrastructure.

Why Build This

Develop reliable remote home monitoring systems capable of operating independently of standard Wi-Fi or internet infrastructure.

Implement SMS-based security alerts that transmit immediate warning messages directly to a user's mobile phone during trigger events.

Prototype IoT device control architectures that utilize cellular networks for wide-area data transmission and remote command execution.

Real-World Application

Remote home monitoring systems, SMS-based security alerts, and IoT device control via cellular networks without internet dependency.

Skills You'll Learn

UART serial communication

AT command protocol parsing

external power management

cellular network interfacing

microcontroller peripheral integration

Safety Precautions

Ensure an adequate external power supply capable of delivering up to 2A of surge current to prevent continuous module resetting.

Technology Tags

ARDUINO

SIM900

GSM

GPRS

CELLULAR

AT COMMANDS

SOFTWARESERIAL

Frequently Asked Questions

Can I power the SIM900 shield directly from the Arduino's 5V pin?

No, the Arduino's internal regulator cannot supply the high surge current (up to 2A) required by the SIM900 during network transmission, which will cause the module to continuously reset.

What kind of SIM card do I need for this project?

You need a standard 2G full-size SIM card that is active and compatible with local cellular frequency bands supported by the SIM900 module.

How does the Arduino communicate with the SIM900 shield?

The Arduino communicates with the shield using serial communication by sending standard AT commands to execute tasks like dialing numbers or sending text messages.

Gallery

This page is part of Kitkraft's Project Hub — a curated collection of electronics & robotics projects gathered from the maker community to help students and hobbyists discover and learn to build. Kitkraft does not claim authorship of the original project, and makes no representation as to the accuracy, completeness or safety of third-party source material. The summary and "How It Works" explanation above are AI-generated, rewritten with reference to the original tutorial — not a reproduction of it. Full credit and a direct link to the original source are provided above. If you're the original creator and have a concern about how your work is represented here, please contact us and we'll address it promptly.

Kitkraft Project Hub — curated from the maker community, credited at the source.

PRJ-01436