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GSM module Interfacing with PIC Microcontroller - Make and Receive Calls

Intermediate

PIC

₹1,500 – ₹5,000

3 – 6 Hours

Partial Kit

GSM module Interfacing with PIC Microcontroller - Make and Receive Calls

Learn how to interface a GSM module (SIM900A) with a PIC16F877A microcontroller to make and receive phone calls using AT commands.

Originally published on CircuitDigest

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.

2-Slot 18650 Holder with Protective Cover and On/Off Switch – Case Rs. 109.00
MB102 Adjustable Breadboard Power Supply Module (3.3V & 5V) for Arduino & Raspberry Pi Rs. 139.00
Jumper Wire 10 Pin Male To Male 20cm Rs. 45.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality Rs. 89.00
Jumper Wire 10 Pin Male To Female 20cm Rs. 45.00

Selected: Rs. 0.00

We don't carry yet: LCD (generic / unspecified)
PIC Microcontroller
GSM / GPRS SIM800L

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How It Works

This project integrates a PIC16F877A microcontroller with a SIM900A GSM module to enable cellular communication, allowing the system to make and receive phone calls. The microcontroller serves as the central processing unit, communicating with the GSM module via serial communication using AT commands. Push buttons connected to the PIC microcontroller allow the user to manually trigger calling actions or input phone numbers. As the system operates, the 16x2 LCD display provides real-time visual feedback, showing the current status of the network connection, incoming call notifications, or outgoing call progress. Powering the entire setup requires a stable 12V/2A external power supply, which is necessary to handle the instantaneous high-current demands of the GSM module during cellular transmission without causing voltage drops that could reset the microcontroller. The firmware, written using the MPLAB XC8 compiler, handles the logic for interpreting button presses, sending appropriate AT commands to the cellular modem, and updating the LCD screen to reflect the current state of the device.

Why Build This

Design remote monitoring and security alert systems that can notify users via phone calls during critical events.

Develop automated emergency calling devices for undergraduate engineering capstone or prototype demonstrations.

Gain practical experience implementing serial communication and AT command protocols between microcontrollers and cellular hardware.

Real-World Application

Remote monitoring systems, security alert systems, automated emergency calling devices, and remote appliance control via phone.

Skills You'll Learn

UART serial communication

AT command protocol parsing

LCD interfacing

microcontroller GPIO management

power supply load management

Safety Precautions

Ensure proper power supply voltage regulation for the GSM module, as high current spikes during transmission can cause instability or reset the microcontroller.

Technology Tags

GSM

SIM900A

PIC MICROCONTROLLER

AT COMMANDS

UART

TELEPHONY

Frequently Asked Questions

Can I power the GSM module directly from the PIC microcontroller's 5V pin?

No. The SIM900A module draws high current spikes during cellular transmission that far exceed what a microcontroller pin or onboard regulator can supply, requiring a dedicated 12V/2A external power supply.

What software is needed to program the PIC16F877A microcontroller?

You will need the MPLAB XC8 Compiler to write and build the C code, along with a suitable hardware programmer to flash the compiled hex file onto the microcontroller.

How does the microcontroller communicate with the GSM module?

The PIC microcontroller communicates with the SIM900A module using UART serial communication by sending and receiving text-based AT commands.

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.

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