Stringman, an $800 open-source room scale gripper robot
An open-source, $800 ceiling-mounted “cable robot” called Stringman uses four tensioned lines and a gripper to move around a room and pick up objects, prompting both admiration for its ingenuity and skepticism about its practicality in typical homes. Commenters weigh its strengths—low cost, large working volume, and suitability for workshops, agriculture, or industrial automation—against drawbacks like visible cables, limited payload, safety concerns around children and pets, and the need for relatively uncluttered, rectangular spaces. The project also feeds into a broader debate over whether future domestic robots should be humanoid to fit existing environments or embrace alternative forms like ceiling systems, mobile “garbage can” bots, or swarms of smaller specialized machines.
Overall reception
- Many commenters find the idea clever, fun, and refreshingly inventive; the slogan about “tension” is widely appreciated.
- Others think it looks janky, like a rough prototype or “overpriced claw machine,” and not up to consumer-product polish.
- Some praise the $800 price as impressive for what it does; others still call it “crazy expensive” for home use.
Use cases and environments
- Home tidying: picking up kids’ toys and clothes is the flagship use; several people say this would have saved them hours in childhood.
- Integration ideas: coordinate with a Roomba, carry a vacuum or mop, or swap tools at a docking station.
- Industrial / workshop: moving parts between stations, overhead manipulators in controlled spaces, CNC-like uses, and comparisons to Skycam, Hangprinter, Maslow CNC, and bridge cranes.
- Outdoor concepts: garden weeding, dog-poop pickup, agriculture, and Halloween ghost rigs; many note outdoor robustness would be much harder.
- Accessibility: some imagine overhead harnesses or in-home helpers for people who can’t easily bend or pick things up.
Technical design and kinematics
- Recognized as a suspended cable-driven parallel robot with four actuators, using gravity for tension.
- Discussion on 4 vs 3 cables: three can define a point but only under a triangle; four fit rectangular rooms better.
- Suggestions: extra “Z” cable for vertical motion, crossed taut ceiling wires plus a drop line, multi-gripper setups, CoreXY-like schemes, and automatic retraction to the ceiling when idle.
- Concerns about wobble/swing, cable slack over time, and operation around ceiling fans and light fixtures.
Safety concerns
- The creator states a per-line tension limit around 28 N with damped release; payload vs safety is a tradeoff.
- Some argue this plus flexible line makes strangulation or serious injury unlikely; others worry about toddlers, pets, and anchored ends of cables.
- Debate splits between “users must be responsible / toddler-proof your house” vs “consumer products must assume low risk awareness and provide physical fail-safes.”
Form factor and future robots
- Long subthread debates humanoid robots vs ceiling-mounted or non-humanoid designs.
- Many argue ceiling robots, small mobile robots, or R2D2-like forms are more practical and efficient; others stress that humanoid shapes match a world already built for humans.
- Some foresee a diverse “golden age” of specialized robot forms before any convergence.