1 · What is a robot? (sense → think → act)
When people picture a robot, they usually think of a metal person. But engineers think about it differently. A robot is a machine that can sense the world around it, think about what it senses, and then act to do something useful. That three-step loop is the whole idea — and once you see it, you'll spot it everywhere.
Engineers give those three steps names:
| Step | Engineer's word | Plain English | Example |
|---|---|---|---|
| Sense | Sensor | a part that measures something | a button, a light or temperature sensor, a camera |
| Think | Controller | the "brain" that decides what to do | a tiny computer chip |
| Act | Actuator | a part that makes something move or happen | a motor, a light, a speaker, a wheel |
So the pattern is: sensor → controller → actuator. A robot vacuum senses a wall with its bumper, its controller thinks "turn," and a motor (the actuator) acts by steering away. A self-driving feature senses the car ahead, thinks "too close," and acts by braking.
Here's a surprise: lots of things are robots, or close to it. An automatic door senses you and opens. A thermostat senses the temperature and turns the heat on. None of them look like a metal person — but they all sense, think, and act.
Even NASA's Mars rovers follow this exact loop. A rover senses the ground with cameras, its onboard computer thinks about the safest path, and motors act to drive it forward — NASA says Perseverance can even build a map of the road as it drives and steer itself up to 200 meters in a day (NASA, n.d.-a).
Try this (no kit needed). Pick three machines in your home (a microwave, a phone, a washing machine). For each one, name its sensor, its controller, and its actuator. If you can't find all three, that's interesting too — ask which step is missing.
Check yourself. In your own words, what are the three things every robot does?
Sources
NASA. (n.d.-a). Robotics. National Aeronautics and Space Administration. https://www.nasa.gov/robotics/ NASA. (n.d.-b). Mars 2020 Perseverance rover components. NASA Science. https://science.nasa.gov/mission/mars-2020-perseverance/rover-components/