Note: Close-Range Sensing and Ultrasonic Safety

You are probably here because the robot is fine in the large, but still clips furniture, misses chair legs, or needs a cheap last-line obstacle signal near the bumper.

Likely First Answer

Start with Ultrasonic Sensors for Robot Safety.

If the Real Problem Is...

• feeding close-range data into Nav2: Nav2 Range Sensor Layer for Close Obstacles
• unreliable host-MCU transport: Serial Protocols Between ROS 2 and Microcontrollers
• safety behavior design: Emergency Stop Integration
• broader heartbeat and fault handling: Hardware Watchdogs and Heartbeats

Shiny Objects Nearby

• Collision Monitor and Safety Polygons
• Laser Scan Processing and Filtering
• Lidar Filter Chains and Self-Hit Removal