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This project implements a compact, long-range audio monitoring system using the IndusBoard Coin microcontroller platform paired with a SIM800L GSM cellular module. The core functionality relies on cellular communication networks rather than short-range radio frequencies, allowing the device to transmit and receive signals over theoretically limitless distances where cellular coverage is available. Powering the system is a 3.7V Li-Po battery managed by a dedicated BMS module, which ensures safe charge and discharge cycles, protecting the energy storage element from over-voltage or deep depletion. The IndusBoard Coin acts as the central processing unit, running code compiled through the Arduino IDE. It interfaces with the SIM800L module via serial communication, utilizing libraries such as Adafruit FONA and HardwareSerial to manage cellular commands, network registration, and call handling. An attached microphone module captures ambient audio signals in the immediate vicinity of the device. When triggered, the microcontroller instructs the SIM800L to place a cellular call to a pre-programmed destination number. Once the connection is established over the cellular network, audio captured by the microphone module is transmitted across the call, enabling remote listening capabilities. An optional UFL flexible GSM antenna can be connected to the SIM800L to optimize cellular signal reception in constrained spaces, ensuring reliable connection stability during operation.
Why Build This
Design and implement a long-range remote monitoring node utilizing cellular infrastructure and embedded microcontrollers suitable for undergraduate engineering applications.
Integrate power management systems, including Li-Po batteries and BMS modules, to ensure reliable, portable operation for remote electronic deployments.
Develop advanced serial communication firmware using the Arduino IDE and specialized libraries to bridge microcontroller logic with cellular transceivers.
Real-World Application
Security, remote monitoring, and covert audio surveillance.
Skills You'll Learn
Cellular module interfacing
AT command communication
serial hardware communication
Li-Po power management and BMS implementation
audio signal capture
microcontroller firmware development
Safety Precautions
Strictly intended for security and surveillance; must not be used for unauthorized purposes or wiretapping without consent.
Technology Tags
GSM
SIM800L
INDUSBOARD COIN
ARDUINO IDE
ADAFRUIT FONA
AUDIO SURVEILLANCE
WIRELESS COMMUNICATION
Frequently Asked Questions
Lithium-polymer batteries are sensitive to overcharging, deep discharge, and short circuits. The BMS module protects the battery by regulating voltage thresholds to ensure safe operation.
No, this specific architecture relies on the SIM800L GSM module to leverage cellular networks, enabling long-range audio transmission far beyond the typical range of local Wi-Fi routers.
The FONA library simplifies communication with cellular modules by providing pre-written functions to handle complex tasks like initiating calls, checking network status, and sending commands via serial.
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.
Microphone module - Analog Sound Sensor Module for Arduino
Rs. 63.00
400 Points Mini Solderless Prototype PCB Breadboard High Quality
Rs. 89.00
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
Jumper Wire 10 Pin Male To Female 20cm
Rs. 45.00
