How one cybersecurity professional turned the Apollo MTR-1 into the ultimate portable hotel security system
When cybersecurity expert Dan Tentler travels for conferences, he doesn't just pack his laptop. He brings an entire smart security system. In his eye-opening SEC-T 0x11 presentation titled "How to bug hotel rooms v2.0," Tentler demonstrated how he transformed the Apollo Automation MTR-1 mmWave sensor into a sophisticated hotel room monitoring solution that detects unauthorized entry while maintaining complete privacy.
The Problem: Hotel Room Security Risks
For travelers carrying expensive equipment or sensitive information, hotel security is a genuine concern. Traditional hotel room security leaves much to be desired, and travelers often wonder if someone has gained access to their room while they weren't there. Business travelers, conference attendees, and security professionals face unique risks when leaving valuable equipment unattended in unfamiliar locations.
The Solution: Tactical Home Assistant Deployment
Tentler's innovative approach leverages commercial smart home technology for tactical security applications. By using Home Assistant to automate security monitoring, he created a system that can send alerts, control lights, make sounds, take pictures, and perform various other automation tasks. The centerpiece of this portable security kit is the Apollo MTR-1 Multi-Target Radar Multisensor.
Why the MTR-1 Excels for Hotel Security
The Apollo MTR-1 offers several features that make it ideal for temporary security deployments:
Officially Certified for Home Assistant The MTR-1 is fully certified in the Works With Home Assistant program and carries the Made For ESPHome designation. These certifications ensure seamless integration, reliable performance, and ongoing compatibility with the Home Assistant ecosystem. This professional validation means the device meets rigorous standards for quality, security, and user experience.
Multi-Target Tracking Capability The MTR-1 uses an HLK-LD2450 mmWave radar sensor that can track up to three targets simultaneously across three configurable zones within approximately 6 meters. This multi-target capability means you can monitor not just if someone enters your room, but exactly where they are and how they're moving through the space.
Through-Wall Detection Perhaps the most intriguing aspect of Tentler's setup is the sensor's ability to detect through certain materials. mmWave radar units can see through walls, enabling users to detect if someone is outside their room or even in adjacent rooms. This creates an early warning system that alerts you before someone even attempts to enter.
Compact and Portable At just 49mm × 32mm × 15mm, the MTR-1 is incredibly compact and easily fits into luggage. It's powered via USB-C, requiring only a standard wall plug with no special power requirements or installation needed.
Local Processing Unlike cloud-based security cameras, the MTR-1 operates entirely locally through Home Assistant and ESPHome. Your security data never leaves your network, ensuring complete privacy. This is a critical consideration for security-conscious professionals.
CO2 Sensor: The Secret Presence Detector
Beyond motion detection, Tentler also utilized the MTR-1's optional CO2 sensor module for presence detection. This clever dual-purpose approach provides several advantages:
Passive Presence Confirmation CO2 levels rise when people occupy enclosed spaces due to respiration. By monitoring CO2 concentration, the system can confirm human presence even when subjects remain completely still. This is something traditional motion sensors struggle with.
Environmental Awareness The CO2 sensor serves double duty by also monitoring air quality. High CO2 levels in hotel rooms can cause poor sleep, drowsiness, and brain fog. This provides useful information for travelers adjusting to new environments.
Correlation Data By combining mmWave motion data with CO2 readings, the system can more accurately distinguish between false positives and genuine intrusions, reducing alert fatigue.
Privacy-First Security: No Cameras Required
One of the most compelling aspects of this approach is that it achieves comprehensive security monitoring without using cameras. This addresses several concerns:
- Guest Privacy: Hotels often prohibit security cameras; mmWave sensors don't capture images
- Legal Compliance: Avoids jurisdictional issues around video recording in hotel rooms
- Data Minimization: Collects only motion and environmental data, not visual information
- Professional Ethics: Security professionals can protect their space without ethically questionable surveillance
Setting Up Your Own Hotel Security Kit
For those interested in replicating Tentler's approach, the basic components include:
- Apollo MTR-1 with optional CO2 sensor
- Portable Home Assistant instance (Raspberry Pi or laptop-based)
- USB-C power adapter
- ESPHome configuration for alert customization
The MTR-1's open-source nature means you can fully customize alerts, detection zones, and automation rules to match your specific security requirements.
Key Automation Ideas
- Entry Alerts: Instant phone notifications when motion is detected in the entry zone
- Lighting Responses: Automatic light activation to deter intruders
- Audio Warnings: Piezo buzzer activation to alert nearby occupants
- Visual Indicators: RGB LED color changes to indicate security status
- CO2 Monitoring: Alerts when CO2 levels suggest prolonged occupancy in your absence
- Zone-Based Logic: Different responses for different areas (entrance vs. interior)
Beyond Hotels: Broader Applications
While Tentler demonstrated this system for hotel security, the applications extend far beyond travel scenarios:
- Office Security: Monitor sensitive work areas after hours
- Temporary Workspaces: Secure co-working desks and shared offices
- Vacation Rentals: Property owners monitoring guest spaces
- Conference Rooms: Track usage and unauthorized access
- Storage Units: Detect intrusion without permanent installation
The Power of ESPHome and Home Assistant
Home Assistant enables the creation of sophisticated automation rules with ease, demonstrating that the platform can be deployed tactically for security applications. The system's flexibility allows users to:
- Create custom alert conditions
- Integrate multiple sensors
- Build complex automation logic
- Access real-time dashboards remotely
- Log historical data for forensic analysis
All of this runs locally on your network, giving you complete control over your security data without relying on cloud services that could be compromised or subpoenaed.
Technical Specifications
For those interested in the technical details of the Apollo MTR-1:
Detection Capabilities:
- Multi-target tracking (up to 3 simultaneous targets)
- 6-meter maximum detection range
- Multi-zone configuration (typically 3 zones)
- X-axis detection: -3000mm to +3000mm
- Y-axis detection: 0 to 6000mm
Environmental Sensors:
- LTR-390UV for ambient light (Lux) and UV index
- DPS310 for temperature and barometric pressure
- Optional SCD-40 CO2, temperature, and humidity module
Connectivity & Control:
- ESP32-C3 Mini WiFi module
- ESPHome firmware (open-source)
- USB-C power input
- Bluetooth LE support for device tracking
Feedback Systems:
- RGB NeoPixel LED for visual status
- Piezo buzzer for audio alerts
Real-World Performance Considerations
Based on reviews and community feedback, several factors affect mmWave sensor performance in hotel environments:
Material Penetration: Detection through walls varies by construction material. Modern hotels with concrete and steel may limit through-wall detection compared to older wood-frame structures.
Tuning Requirements: The LD2450 sensor in the MTR-1 requires zone configuration to minimize false positives. Spending 10-15 minutes tuning detection zones for your specific hotel room layout significantly improves accuracy.
Static Detection Limitations: The LD2450 is optimized for tracking moving targets. If security monitoring requires detecting completely stationary individuals for extended periods, consider supplementing with the CO2 sensor or using the Apollo MSR-2 for better static presence detection.
Interference: Other electronic devices in hotel rooms rarely cause issues, but microwaves and certain industrial equipment can potentially interfere with mmWave operation.
Privacy and Legal Considerations
Before deploying any security monitoring in hotels:
- Check Hotel Policies: Review terms of service regarding electronic security devices
- Respect Others' Privacy: Ensure detection zones don't extend into hallways or adjacent rooms without justification
- Data Handling: Keep all data local and secure; consider encryption for sensitive deployments
- Disclosure: For business travel, verify company policies on personal security devices
Community Response and Future Development
Tentler mentioned potential future considerations including manufacturing and selling kits for deployment if the audience showed sufficient interest. The security community's response to his presentation has been enthusiastic, with many professionals exploring similar approaches for their own travel security needs.
The Apollo Automation community continues to expand the capabilities of their sensors through:
- Open-source firmware updates via GitHub
- Community-contributed integrations and automation blueprints
- Tutorial content on the Apollo Wiki
- Active Discord community providing deployment support
Why This Matters for Smart Home Enthusiasts
Tentler's hotel security kit demonstrates the maturity and versatility of Home Assistant as a platform. What started as home automation software now powers portable, tactical security deployments. This showcases several important trends:
Platform Versatility: Home Assistant isn't just for controlling lights. It's a serious automation and monitoring platform suitable for professional security applications.
Privacy-Conscious Technology: As concerns about IoT privacy grow, locally-processed solutions like ESPHome-based sensors offer compelling alternatives to cloud-dependent systems.
Open-Source Advantage: The ability to customize firmware, create unique automations, and adapt hardware for novel use cases stems directly from Apollo Automation's commitment to open-source development.
Accessible Advanced Technology: What would have required expensive commercial security equipment a decade ago is now achievable with consumer-grade smart home technology costing under $100.
Getting Started Resources
For those inspired to build their own portable security system:
Essential Documentation:
- Apollo MTR-1 Wiki: Official documentation and setup guides
- Apollo Automation GitHub: Open-source firmware and CAD files
- ESPHome Documentation: Learn ESPHome configuration
- Home Assistant Community Forums: Share experiences and get support
Video Resources:
- Dan Tentler's SEC-T Presentation: Full security kit demonstration
- Apollo Automation YouTube Channel: Product tutorials and live streams
Purchase Information:
- Apollo MTR-1: Base sensor
- MTR-1 with CO2: With environmental monitoring
- Mounting accessories and expansion options available
Conclusion: Smart Home Technology Meets Real-World Security
Dan Tentler's innovative use of the Apollo MTR-1 demonstrates how smart home technology has evolved beyond simple convenience features into legitimate security tools. By combining mmWave radar multi-target tracking, CO2 presence detection, and local Home Assistant automation, he created a portable security solution that respects privacy while providing comprehensive monitoring.
For security professionals, frequent travelers, and privacy-conscious individuals, this approach offers a compelling alternative to traditional hotel security measures. The system operates entirely locally, processes data on your network, costs under $100, and requires no installation or modification to the hotel room.
As mmWave sensor technology continues to advance and the Home Assistant community grows, we can expect even more innovative applications of these tools. Whether you're protecting valuable equipment during conference travel, securing temporary workspaces, or simply want peace of mind in unfamiliar lodging, mmWave presence detection combined with environmental monitoring provides a powerful, privacy-respecting solution.
The future of personal security may not involve more cameras. It might involve smarter, more respectful technologies that protect without invading. Dan Tentler's hotel security kit shows us that future is already here.
Interested in building your own tactical security kit? Join the Apollo Automation community on Discord to share your deployment, get support, and contribute to the ongoing development of open-source smart home security solutions.
Keywords: hotel room security, mmWave presence detection, Apollo MTR-1, Home Assistant security, travel security system, CO2 presence sensor, local smart home, ESPHome security, portable monitoring system, privacy-first security, multi-target radar, tactical automation
