Researchers have developed an unusual robot inspired by the unpredictable movements of Mexican jumping beans.

Called BeanBot, the device moves without motors, batteries, electronics, or onboard computing, relying instead on its interaction with the surrounding environment.

Its motion can vary dramatically depending on the surface and conditions it encounters, allowing it to hop, roll, flip, or slide in unexpected ways.

The researchers say the robot demonstrates a new form of movement driven by simple physical interactions, offering insights into how machines could navigate complex environments without conventional control systems.

Heat-powered robot

Researchers at the Italian Institute of Technology’s Bioinspired Soft Robotics department have developed BeanBot, which is a small robot that can jump, roll, flip, slide and climb slopes without motors, batteries, sensors or a computer.

The robot was inspired by the Mexican jumping bean, whose unusual movements come from a moth larva living inside a seed pod. Instead of copying the animal directly, the researchers combined its heat-driven movement with the shape of the bean’s shell to create a robot that can move in several different ways.

Bean-Bot is built from two main parts: a tiny heat-responsive spring and a lightweight, bean-shaped shell. The spring is made from a shape-memory alloy (SMA), a material that changes its shape when heated. Magnets hold the spring in place while it stores energy. When the spring gets hot enough, it suddenly releases that energy, pushing the robot off the ground and sending it into the air. The shell then determines what happens next.

The robot does not have a system that tells it when to jump, roll, or flip. Instead, its body shape and the surface beneath it decide how it moves. The shell has one curved side and two flat sides, giving Bean-Bot different ways to interact with the ground. The curved side allows it to roll, while the flat sides help it stay stable and can allow it to climb an incline. The shape also helps the robot turn itself over after landing, allowing it to jump again even if it lands in a different position.

This simple design gives Bean-Bot a surprisingly wide range of movement. Researchers found that it can jump as high as about 30 centimetres, roll distances of around 80 centimetres, slide across smooth surfaces and flip through the air or after hitting the ground. It can also climb slopes between 10 and 18 degrees when its magnetic force is adjusted. These movements are produced by the same heat-powered spring rather than separate motors or mechanisms.

Robot harnesses surfaces

The robot’s movements can also change depending on the surface it lands on. On a smooth surface, a jump may send it mostly upward or cause it to slide. A rougher surface can make it roll, while irregular ground can change the direction and height of its jump. In tests of 92 jumps, about 81.5 percent developed into additional movements such as rolling, sliding, bouncing, or flipping after the initial jump. This means the robot’s surroundings effectively become part of its movement system.

Bean-Bot is also extremely simple compared with conventional robots. Its shell weighs about 3.8 grams, while the jumping module is about 8 grams. The complete system uses a 3D-printed shell, an SMA spring and magnets, with no onboard electronics needed to control its movements.

There are limits to the design. The SMA spring currently needs temperatures of about 70–80°C to trigger a jump, and the robot can take 30 to 180 seconds to activate and around 130 to 140 seconds to recover before another cycle. The researchers say future improvements to the materials could make Bean-Bot respond at lower temperatures and move more quickly.

The researchers see Bean-Bot as an example of a different approach to robotics, where a robot’s body can do some of the work normally handled by sensors, computers and software. Instead of programming every movement, they designed the robot so that its shape, materials and surroundings naturally produce different behaviours.