DFRobot Gravity Digital Crash Sensor (Left Side)

A collision or bumper sensor needs to be mechanically robust rather than delicate, since its entire job is to survive repeated physical contact - this module uses a genuine snap-action switch mechanism paired with a roller lever, the same reliable design principle found in limit switches, rather than a more fragile touch or capacitive sensing approach that could be damaged by an actual impact. The roller lever specifically reduces friction and wear compared to a plain lever tip dragging against a surface or obstacle.

A clean digital output with an onboard pull-up resistor means it wires directly into a microcontroller's digital input with no additional signal conditioning needed, and an onboard status LED gives immediate visual confirmation of trigger state during testing and debugging. Direct compatibility with DFRobot's IO Expansion Shield keeps wiring simple on Arduino-based robots already using that ecosystem, and two M3 mounting holes make secure physical attachment to a robot chassis straightforward.

Common uses are robot bumper collision detection (this being the left-side-oriented version for asymmetric bumper layouts), edge-detection on line-following or maze-solving robots, and general mechanical limit/collision sensing wherever a reliable physical switch beats a contactless sensor.