Earlier versions of the DIY IndusPhone demonstrated the feasibility of building an ultra-compact touchscreen phone, but they relied on a 2G GSM module and ran individual functions separately. With 2G networks becoming obsolete and increasing system complexity, there was a need for modern network compatibility, better task management, and a unified software architecture that could handle real-time phone operations smoothly.
This final iteration of the DIY IndusPhone delivers a fully integrated, RTOS-based miniature smartphone powered by a 4G LTE GSM module. It consolidates all core phone functionalities—calling, messaging, UI interaction, and basic applications—into a single, well-managed system suitable for modern cellular networks.
Check Part 1 and Part 2 of this project.
Key Features
- 4G LTE connectivity using the A7670C GSM module for improved network compatibility
- RTOS-based architecture to manage multitasking and real-time operations
- Compact touchscreen UI with integrated dialer, contacts, and home screen
- Built-in applications such as a calculator and essential utilities
- Electret condenser microphone and SMD speaker for voice communication
- Real-time monitoring of incoming calls, battery level, touch input, signal strength, and messages
- Interrupt-driven buzzer alerts for incoming calls
- Low-power 3.3V battery operation, optimized for small form-factor devices
Applications
- Educational and DIY electronics projects
- RTOS learning and embedded systems training
- Compact communication devices and experimental form-factor phones
- Prototyping for ultra-small IoT and wearable communication products
- Demonstration platform for UI development on constrained hardware
By combining modern 4G connectivity with an RTOS-driven software framework, the IndusPhone project demonstrates how complex smartphone-like functionality can be achieved on minimal hardware. This final design not only future-proofs the device against legacy networks but also serves as a powerful reference for developers exploring real-time embedded systems, compact UI design, and next-generation DIY mobile devices.