Hello All,

I am currently building a 7DOF arm; I am looking to achieve dual-sided mounting for J2 and J4. I came across this picture of a robotic assembly, and as an engineer, I am really curious. Geared rotary actuators have output only on one side, and the links get mounted on that side. How is the link mounted on the two sides of an actuator? Especially, what is that black, disc-shaped thing with a hex nut in the center?

https://i.postimg.cc/hPLWtfwp/image.png

Hi everyone I’m building a Mantis Bot using an Arduino Nano and servos rated for a maximum of 6V, with a stall current of 750mA each. I’m planning to use two 3.7V batteries in series (7.4V total).

Any ideas on how to power the Nano and servos safely without using additional modules?

Hi everyone,

I’m a final-year student building an autonomous tracked robot for reconnaissance in collapsed-structure (rubble) environments. It enters confined voids, builds a map, and searches for signs of life before human responders enter. The robot moves slowly and uses a stop-and-scan routine: it stops, scans its surroundings, then advances.

⚙️ Current Hardware Stack:

• Chassis: Metal tracked chassis with suspension (12V encoder motors)
• Compute: Raspberry Pi 5 (8GB) for perception/SLAM + ESP32 for real-time motor control
• Sensors: RPLIDAR A1 (2D), Camera on a pan-tilt arm (360° bus servo for pan)
• Constraints: Battery-powered, limited budget, ~6 months to build and test

⚠️ My Concern:

The RPLIDAR A1 only scans a single horizontal plane. In rubble, the robot will pitch and roll, tilting the scan plane and missing overhangs, obstacles above/below the plane, or holes in the floor. I need 3D awareness to avoid unsafe navigation, but a true 3D LiDAR is far beyond my budget. I’m unsure whether a depth camera (e.g., RealSense D435i or OAK-D Lite) is the right alternative.

❓ Questions for the Community:

1. RGB-D Camera for Mapping: Can an RGB-D camera completely replace the LiDAR for mapping here, or should it only supplement it? What is your experience with visual SLAM on vibrating tracked platforms, especially in dark, dusty, or textureless voids?
2. 3D LiDAR vs Compromise: For a student prototype, is a true 3D LiDAR ever justified, or is a 2D LiDAR / depth camera combo the standard sensible compromise?
3. Pi 5 Performance: Can a Raspberry Pi 5 realistically run RTAB-Map (RGB-D) alongside object detection? How do you manage the CPU load (reduced resolution/FPS, hardware acceleration, cooling, etc.)?

Any advice, repo links, or past experience reports would be hugely appreciated. Thank you!