SIPClient – Android App for Video Intercom & MQTT-based Home Control

SIPClient is an Android application that enables video communication with home intercom-like devices based on Raspberry pi 3&5 over SIP (Linphone) and allows remote control of GPIO (light, bell) on Raspberry Pi 3 using MQTT. It's designed to work in a local or VPN-based network (e.g. WireGuard).

---

📸 Features

• 📞 SIP-based video calls with Linphone Core SDK
• 🏠 Dedicated buttons for connecting to home and garage devices
• 💡 Remote control of light and bell via MQTT (GPIO 17 and 27)
• 🔁 Automatic state synchronization via retained MQTT messages
• 🔐 MQTT authentication with local credential storage
• 📶 Network-aware behavior: connects only when a valid network is available
• 📱 Optimized layout for mobile portrait mode

---

🧰 Architecture Overview

+---------------------+                          +------------------+
|      Android App    |                          |  Raspberry Pi 5  |
|---------------------|                          |------------------|
| SIP (Linphone)      |<------ SIP over VPN ---->| linphone-daemon  |
| MQTT (Paho)         |                          | Mosquitto Broker |
+---------------------+                          +------------------+
            ^
            |
            | MQTT (tcp://10.8.0.1)
            | SIP over VPN
            v
+---------------------+
|  Raspberry Pi 3     |
|---------------------|
| MQTT subscriber     |
| linphone-daemon     |
| GPIO 17 -> light    |
| GPIO 27 -> bell     |
+---------------------+

---

🗝️ MQTT Topics

Topic	Description	Retained	Type
gpio/17	Light control	✅ Yes	on/off
gpio/27	Bell control	✅ Yes	on/off

---

🔐 MQTT Credentials

On first app launch (with internet access), user is prompted to enter:

• Username
• Password

These credentials are securely stored using SharedPreferences and reused automatically.

🔒 Credentials are not hardcoded in the source code.

---

🧠 Logic Summary

• Pressing Call Home or Call Garage in Android app initiates a SIP call.
• When the call is established with garage (10.8.0.2), UI shows light and bell switches.
• Switch state changes are published to MQTT and retained.
• On app start, retained messages restore UI state automatically.

---

📦 Dependencies

• Linphone SDK
• Eclipse Paho MQTT Client

---

✅ Permissions Required

• INTERNET
• RECORD_AUDIO
• CAMERA

---

🚀 Build & Run

Prerequisites:

• Android Studio (Arctic Fox or newer)
• SDK 31+
• Network access to MQTT broker and SIP devices (typically via WireGuard VPN)

note: pi3 MQTT client has to be run at least once from the console, in order to set MQTT user & password.

📄 License

This project is released under the MIT License.