Week 1
What Makes Something a Robot?
Sort robots from ordinary machines, and map how a robot senses, thinks, and acts.
- 60-75 minutes
- Mission: Decide what counts as a robot, then map and design a robot that does one helpful job.
Students figure out what actually makes something a robot instead of just a machine. They learn that a robot senses the world, decides what to do, and then acts - the input, processing, output loop - and that a program is what makes it repeat the job on its own. They investigate real devices, map one as a robot system, and sketch a helpful robot of their own.
By the end of this week you can
- Explain what makes something a robot rather than a simple machine
- Describe the input, processing, output loop in a real device
- Explain the role of the controller as the robot's brain
- Identify the sensors and actuators in a robot
- Tell the difference between autonomous and remote-controlled systems
- Design a robot system for a useful task
- Sketch a helpful robot and label its inputs, processing, and outputs
Learn
What a robot really is
People call all sorts of things robots, but a real robot has three abilities: it can sense the world, decide what to do, and act - and it can do this on its own by following a program.
A toy car you push is not a robot. A car that notices a wall in front of it and stops by itself is closer to one, because it senses and decides.
For example: A robot vacuum; A self-checkout that scans items; An automatic door that senses you coming
Machines vs robots
Every robot is a machine, but not every machine is a robot. A stapler and a bicycle are machines: they do work, but a person makes every decision.
The dividing line is sensing and deciding. If the device can take in information and change what it does because of it, it is acting like a robot.
For example: Bicycle = machine; Robot vacuum = robot; Toaster with no sensor = machine; Toaster that senses when bread is done = robot-like
Inputs, processing, and outputs
Robots work in a loop: input, then processing, then output. First a sensor gives an input (like 'wall is close'). Then the controller does the processing (it decides 'I should stop'). Then an actuator makes the output (the wheels stop).
This loop repeats over and over, many times a second, which is how a robot keeps reacting to a changing world.
The three main parts: controller, sensors, actuators
A robot has a controller (its brain), one or more sensors (how it senses), and one or more actuators (how it acts).
The controller runs the program. Sensors send it inputs. Actuators carry out its outputs. Take away the sensors and it can't sense; take away the controller and it can't decide.
For example: Controller: the small computer board; Sensors: distance, light, touch, color; Actuators: motors, wheels, grippers, buzzers, lights
A program makes it repeatable
A program is the list of instructions the controller follows. Because the robot follows a program, it can do the same job again and again without a person guiding each step.
Change the program and the robot behaves differently, even with the same body and sensors. That is why robotics is as much about instructions as it is about building.
Autonomous vs remote-controlled
An autonomous system runs its own program and uses its sensors to decide, with no person steering. A remote-controlled system does exactly what a person tells it, moment by moment.
A drone flown with a controller is remote-controlled. A robot vacuum that cleans a room by itself is autonomous. Many real robots can do both at different times.
For example: Autonomous: robot vacuum, Mars rover doing a planned drive; Remote-controlled: RC car, a drone on a joystick
Robots and machines all around us
Use the sense-decide-act test on things you see every day. Some are true robots, some are just machines, and some are in between.
An automatic sliding door senses you and opens - it decides. A Mars rover, a programmed robotic arm, and a voice-controlled speaker all sense, decide, and act, so they are robots. A remote-controlled car only does what a person tells it. A basic toaster and a wind-up toy do not sense or decide at all. A washing machine is in between: it senses water and follows a program, but it just repeats fixed cycles.
For example: Robots: automatic sliding door, Mars rover, robotic arm, voice-controlled speaker; Just machines: remote-controlled car, basic toaster, wind-up toy; In between: washing machine
Words to know
- Robot:
- A machine that can sense its surroundings, decide what to do, and act on its own using a program.
- Machine:
- A tool that does work, like a bicycle or a stapler. A machine is only a robot if it can sense and decide by itself.
- Input:
- Information a robot takes in from the world, usually through a sensor.
- Processing:
- The 'thinking' step where the controller uses the inputs to decide what to do.
- Output:
- The action a robot takes, like moving a wheel or turning on a light.
- Controller:
- The robot's 'brain' - the small computer that runs the program and makes decisions.
- Sensor:
- A part that measures something about the world, like distance, light, or touch.
- Actuator:
- A part that makes something move or happen, like a motor, wheel, or buzzer.
- Program:
- A set of instructions the controller follows to do a job the same way every time.
- Autonomous:
- Acting on its own, using sensors and a program, without a person steering it.
- Remote-controlled:
- Steered by a person in real time, for example with a joystick or app.
Stay safe
Read these before you build or run a robot this week.
- Caution:Keep fingers, hair, and loose clothing away from moving wheels and gears on kit robots.
- Caution:Do not open or take apart real appliances; investigate by watching them work.
- Note:Take a short screen break if your eyes get tired using the simulator.
Do it
Choose your path
Do this course with a robot kit, the browser simulator, or unplugged with household materials. Pick one - you can switch anytime without losing your work.
Robot-or-Not investigation
Robot kitSort real devices into robot, machine, or in-between, and defend each choice with the sense-decide-act test.
- Look at each device and ask three questions: Can it sense anything? Can it decide on its own? Can it act? A real robot can do all three by itself.
- Put each device on a line from 'just a machine' to 'full robot', and write one reason for where you placed it.
Investigate your kit robot and three devices
You need: A programmable robot kit, Three everyday devices
Steps
- 1Turn on the kit robot and let it run a simple built-in behavior. Watch what it senses and does.
- 2Compare it to a flashlight, a wind-up toy, and a phone. For each, decide sense/decide/act - yes or no.
- 3Place all four devices on the machine-to-robot line and give a reason for each.
What success looks like: The kit robot lands near the 'robot' end because it senses, decides, and acts; the flashlight and wind-up toy land near 'machine'.
- Every device has a sense/decide/act answer
- Each placement has a written reason
Safety: Keep fingers away from moving wheels and gears while the robot runs.
If it doesn't work
- The robot just drives straight and never reacts
- - Load a behavior that uses a sensor (like stop-at-wall) so students can see it decide.
Go further: Find a device at home that is hard to classify and explain why it sits in the middle.
For each device, decide if it is a robot, somewhere in between, or just a machine. Then tick which parts it really has: does it sense (input), decide (processing), and act (output)? The parts are your evidence - do not go by looks.
1. Automatic sliding door
Your call
What parts does it have?
2. Remote-controlled car
Your call
What parts does it have?
3. Basic toaster
Your call
What parts does it have?
4. Mars rover
Your call
What parts does it have?
5. Washing machine
Your call
What parts does it have?
6. Robotic arm (programmed)
Your call
What parts does it have?
7. Wind-up toy
Your call
What parts does it have?
8. Voice-controlled speaker
Your call
What parts does it have?
0 of 8 devices sorted.
Robot System Mapper
Robot kitMap one real device as a robot system: label its inputs, processing, outputs, controller, sensors, and actuators.
- Pick one device that senses and decides. On the mapper sheet, draw arrows for the input, processing, and output loop.
- Then label the three parts: which piece is the controller, which are the sensors, and which are the actuators.
Map your kit robot
You need: The kit robot, Robot System Mapper worksheet
Steps
- 1Find the controller (the main board), the sensors, and the actuators (motors) on the kit robot.
- 2Fill in the input-processing-output loop for one behavior, such as 'stop before a wall'.
- 3Label each real part on your map.
What success looks like: A finished map showing input (sensor reading) -> processing (controller decides) -> output (motor acts), with real parts labeled.
- Input, processing, and output are all filled in
- Controller, sensor, and actuator are labeled
Safety: Handle the robot gently; do not pull on wires.
If it doesn't work
- Can't tell the sensor from the actuator
- - A sensor measures; an actuator moves. Ask which part causes motion.
Every robot has three jobs: it takes information IN (input), it THINKS about it (processing), and it DOES something (output). Sort each part below into the job it does, then check your work.
- Touch sensor
- Distance sensor
- Color sensor
- Controller
- Motor
- Speaker
- Light
0 of 8 sorted
Helpful Robot design challenge
Robot kitInvent a robot that does one helpful job and sketch it with its inputs, processing, and outputs labeled.
- Think of a small, real problem at home or school that a robot could help with.
- Sketch your robot and label at least one sensor (input), the decision it makes (processing), and at least one actuator (output).
Design a helper, using your kit as inspiration
You need: The kit robot for reference, Pencil and paper
Steps
- 1Look at what your kit's sensors and motors can do for ideas.
- 2Sketch a helpful robot and label its input, processing, and output.
- 3Write one sentence on the job it does and who it helps.
What success looks like: A labeled sketch of a plausible helper robot with a clear job.
- At least one sensor and one actuator are labeled
- The processing decision is written down
- The job and who it helps are named
Safety: No build required this week; this is a design sketch.
If it doesn't work
- The robot has no sensor
- - Ask: how does it know when to act? That is where a sensor goes.
Go further: List which of your kit's real sensors would fit your design.
Helpful Robot design challenge
Design a robot that helps a real person. Break your idea into what it senses, the decision it makes, and what it does. Sketch it on paper, then describe it here.
For example: carrying books, sorting recycling, finding lost objects, watering plants, or inspecting unsafe areas.
Draw your robot on paper and label its parts, then describe the sketch here so it is saved with your design.
Predict
Commit to a guess before you test - then see how close you were. Your predictions save automatically.
How to check: Compare your guess to where the class placed it on the machine-to-robot line after testing sense/decide/act.
Knowledge check
Answer these to check that you can tell robots from machines and name their parts.
1. Decide what kind of system this is.
A toy car drives forward when you push a button on a handset and turns when you move a lever. It never changes what it does on its own.
2. Which of these are actuators? Select all that apply.
Select all that apply.
3. What makes something a robot instead of just a machine?
4. In the input-processing-output loop, what is the 'processing' step?
5. Which part of a robot is the actuator?
6. A robot vacuum cleans a room by itself with no one steering it. This is an example of a system that is:
7. Why does a robot need a program?
0 of 7 answered
Reflect
Your reflections save automatically.
Coming up next week
Next week we stop talking about robots and start building one that actually moves.
- Save a couple of sturdy cardboard boxes and bottle caps if you're on the unplugged path.
- Charge your kit or bookmark the simulator.
- Think about what makes a wheeled thing tip over versus stay steady.
Finish Week 1
Complete these to mark the week done and unlock the next one:
- Complete the Robot System Mapper for one device (not done yet)
- Sketch and label a Helpful Robot (not done yet)
- Score at least 4 of 5 on the knowledge check (not done yet)
- Write your reflection (not done yet)