STEM Coding Max

Model 7: Cleaning robot

The crumb-collecting robot

 

Grade
5-7
Time required
2 double hours
Difficulty level
Model: easy, Programming: medium
Model type
mobile robot / vehicle
Download didactic material

MODEL DESCRIPTION / TASK

The pupils (SuS) plan and realize an autonomously moving cleaning robot for an area. Two sensors on the left and right bumper prevent the robot from moving objects or getting stuck. A signal from these sensors causes the robot to reverse and change direction and then continue moving. For differentiation, an RGB gesture sensor can be installed as fall protection. This allows the device to clean tables without falling. 

EVERYDAY RELEVANCE

The automation of processes and the use of robotic systems is playing an increasingly important role in the everyday lives of students. In addition to existing robotic lawn mowers and vacuum cleaners, other personal assistants and auxiliary vehicles will undoubtedly be added to our lives in the future.

Due to its increasing relevance in everyday life, the topic is suitable for pre-vocational orientation. It arouses students' curiosity about the corresponding everyday technology and professional aspects of the topic of autonomous driving.

Key questions

  • What functions does an autonomous driving robot need to fulfill? (communication, collaboration)
  • What problems can arise when using an autonomous vehicle? (critical thinking)
  • Which aspects of the design must be taken into account for smooth operation? (creativity)

Subject reference

 

Computer sience
Basics of programming various sensors
Technology
transmission theory, vehicle stability, steering systems, manufacturing and optimizing an object, autonomous driving, traffic
Physics
Friction and contact pressure

Lesson progression

 

Introduction phase

Class discussion (without app)

  • Collect various possible autonomous vehicles from the pupils' everyday lives. 
  • Basic technical functions of an autonomous vehicle work out.
  • Presentation of the task.
  • Discuss possible/useful sensors and determine the sensor solution to be implemented and the angle to be used to avoid the obstacle.
  • Discussion of possible ways to implement the attachment and pressure of the wiper unit

Assistance if necessary

  • Show sensors, actuators and components from the construction kit, use presentation media if necessary.
Planning phase

Lesson discussion

  • The procedure for building the model and the function to be achieved are worked out together.
  • Sequence steps of the app are specified or discussed

Partner or individual work (with app)

  • Pupils familiarize themselves with the app and download the corresponding task.
  • Pupils prioritize the functions of the system to be built.
  • Pupils use the app to create a list of requirements for the mechanical parts and sensors of the automatic table wiper. 

Class discussion (without app)

  • The construction of the robot is discussed.
  • Possible materials for the wiping media are discussed and a short test experiment is explained.

Partner or group work (without app)

  • Pupils try out different wiping media (sponge, handkerchief, piece of cloth, kitchen roll) and make a statement about their usefulness in use.

Optional partner or group work (without app)

  • Pupils can optionally sketch the possible system.
  • The pupils discuss the results in the group and decide on a design.
Construction phase

Partner or individual work

  • Pupils use the app to build the robot. The app guides them through the program in small steps.
Programming phase

Partner or group work

  • The pupils write the program for the wiping robot (two buttons as sensors for obstacle detection). The app guides them through the program in small steps.
  • Help is provided in the app.
  • The program is transferred to the RX controller.
Experimentation and test phase

Partner or group work

  • The mopping robot is put into operation, placed on a flat surface and tested.
  • Possible malfunctions in the function sequence must be found and rectified. Help is offered in the app.
  • Any optimizations to the hardware (e.g. contact pressure of the wiping cloth) and the programming of the route (reversing and changing the driving angle) are carried out.
Final phase

Optional: Presentation and allocation of the differentiations

  • The possibility of differentiation for fast pupils is offered in the app.
  • The teacher addresses eligible pupils. The further procedure is realized by the app.

Discussion in plenary

  • Debriefing of the project in class.
  • If necessary, the results of the differentiation are discussed: The use of fall protection and its function is demonstrated.
  • Clarification of how appropriate safety can be achieved with commercial cleaning robots or autonomous vehicles.
  • Clarification of future requirements in everyday solutions (transfer of the topic to everyday life)

 

Information and notes

 

Methodical and didactic tips

 

Differentiation options

The model is particularly suitable for systematically setting up and experimenting with different driving modes by changing the correction angle while driving. Through differentiation, the vehicle can be extended with little effort by an additional sensor (RGB gesture sensor) to increase the degree of autonomy. 
Motivational aspects

There is a great desire to build a vehicle that controls itself as autonomously as possible by using several different sensors. There may also be interest in adding further useful components to the system (e.g. main switch, rear switch, optimization of the wiping function by integrating a drip tank ...). This can be addressed in the classroom discussion.

Additional materials

  • A robot vacuum cleaner if available, otherwise pictures if necessary
  • Drawing media (paper, whiteboard, projection screen)
  • Various wiping media (handkerchief, kitchen roll, sponge, ...)

Building instructions

Circuit diagram

Functions of the modell and their technical solutions

 

Function of the system

 

Technical solution 

 

Triggering the cleaning run 

 

Pressing the start button on the RX Controller

 

 

Frontal cleaning run

 

 

Activation of both motors

 

Hitting an obstacle

 

 

Triggering one of the buttons, stopping the motors

 

Correction of the direction of travel due to an obstacle on the right 

 

 

 (4 pulses) Reversing the vehicle, approx. 20°

turn left, continue travel

 

 

Correction of the direction of travel due to an obstacle on the left

 

Reversing the vehicle, approx. 20° (4 pulses) turn right, contiue travel

 

 

Renewed frontal cleaning run

 

Activate both motors

 

 

Differentiation: Triggering the fall protection at the edge of the table

 

 

Stopping the motors, reversing the motors and counting the pulses, changing the direction of travel, moving on
​

 

Replacing the wiper medium

 

Clamping device for a wiper cloth on the Opening the rear of the vehicle

 

 

Adjusting the wiper medium

 

Adjusting the wiper mounting joint
​

Material list
​

 

 

Sensors

 

 

Function

 

2 buttons

 

 

Obstacle detection

 

2 buttons

 

Pulse coutning of the motors

 

 

Differentiation: 1 RGB gesture sensor

 

 

Prevents falling from an elevated position

 

 




 

Actuators

 

 

Function

 

2 motors

 

 

each for one axis








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