Project Hub /Audio Displays & Interactive Media/LED Matrix & Cube Displays/IndusPhone - Making Smallest Programable Smartphone (Part 3)

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INDUSBOARD

₹1,500 – ₹5,000

6 – 12 Hours

Partial Kit

IndusPhone - Making Smallest Programable Smartphone (Part 3)

This project details the creation of the world's smallest programmable smartphone, upgraded with a 4G LTE GSM module and an RTOS-based firmware architecture.

Originally published on ElectronicsForU

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.

Piezo Buzzer (Big) 6-12V Rs. 45.00
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

Selected: Rs. 0.00

We don't carry yet: Battery (generic / unspecified)
Microcontroller IC (DIP) / Chip
GSM / GPRS SIM800L
Speaker / Audio Amplifier
TFT / Touch LCD
Other Dev Board (Indusboard / Maixduino / misc)
Inductors / Coils / Ferrite
GMI6027P-2C30DB MIC

Browse all components

How It Works

The IndusPhone system is built around the IndusBoard Coin running a Real-Time Operating System (RTOS) to manage concurrent tasks efficiently. Visual output is rendered on the round GC9A01 TFT LCD Screen, while user interaction is handled by the CST816 Touch Chip integrated into the display interface. For audio input and output, the circuit utilizes a GMI6027P-2C30DB microphone, a 12mm SMD buzzer, and a 0.5W SMD speaker driven by appropriate audio circuitry. Cellular connectivity is established using the A7670C 4G GSM Module paired with an external antenna for reliable data transmission and voice communication. Power is supplied via a 3.3V battery, requiring efficient power management to support both the processing core and the power-intensive 4G module during operation.

Why Build This

Develop practical engineering competencies in integrating cellular communication modules into ultra-compact wearable electronics.

Implement multi-tasking firmware architectures using an RTOS to handle concurrent display, touch, audio, and network operations.

Design and optimize power-constrained mobile edge devices powered by low-voltage 3.3V battery systems.

Real-World Application

Miniature wearable communication devices, emergency backup phones, and IoT edge devices.

Skills You'll Learn

RTOS task management

I2C touch controller integration

SPI display interfacing

cellular module AT command communication

audio amplifier and transducer integration

Safety Precautions

No specific precautions noted for this build — always follow general electronics safety practices.

Technology Tags

RTOS

4G GSM

A7670C

TFT LCD

CST816

TOUCHSCREEN

EMBEDDED C

WEARABLES

Frequently Asked Questions

Why is an RTOS required instead of a standard super-loop architecture?

An RTOS is necessary to handle multiple concurrent tasks—such as maintaining cellular network connectivity, refreshing the touch display, and processing audio—without missing critical timing deadlines.

Can any standard battery be used with the IndusBoard Coin?

The system is designed for a 3.3V battery. You must ensure the chosen power source can supply sufficient peak current, especially when the A7670C 4G GSM module transmits data.

How does the touchscreen communicate with the board?

The CST816 Touch Chip typically communicates via an I2C interface, allowing the processor to detect touch coordinates while the GC9A01 screen uses a high-speed display bus like SPI for rendering graphics.

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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