STEM Coding Max

Model 9: Claw machine

Im going to get you!

 

Grade
7 - 10
Time required
3 double hours
Difficulty level
Model: hard, Programming: hard
Model type
mobile device, can be positioned individually and used flexibly
Download didactic material

MODEL DESCRIPTION / TASK

The pupils (SuS) plan and realize an automatic gripper that moves two axes via a hand gesture control and picks up a metal object with a magnet attached to it. After the playing time has elapsed, the object must be transported to the starting position.

The playing time can be changed to differentiate the game.

EVERYDAY RELEVANCE

The automatic triggering of a process has a strong motivational effect on pupils. Understanding the physical quantity “movement” is quick and comprehensible for everyone. The topic could be integrated into pre-vocational orientation with regard to information technology professions. Automated switching through the detection of physical variables is used in many areas here. The detection of movements in particular is becoming increasingly important in many areas of information technology (e.g. gesture control).

 

Key questions:

  • Where can an automatic gripper be used in everyday life? (Communication)
  • What functions does the system need to fulfill? (Collaboration)
  • Under what conditions should the system enable play? (critical thinking)
  • What needs to be considered so that the system can be used in different locations and is as robust as possible? (creativity)

Subject reference

 

Computer sience
Basics of programming, time loops
Technology
Stable contruction, construction technology, component arrangement
Physics
Force, movement

Lesson progression

 

Introduction phase

Class discussion (without app)

  • Announcing the topic
  • Inquire about scenarios in which gripping machines are used (fairgrounds, retail stores, waiting areas, etc.) and which objects can be gripped
  • Basic functional options, e.g. switching on when a coin is inserted, playing time limit... 
    Objects: e.g. sweets, stuffed animals, eggs

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 announced or discussed

Partner or individual work (with app)

  • Pupils familiarize themselves with the app and load the corresponding task.
  • Pupils sort into useful and less useful functions of a gripping machine.
  • Pupils use the app to create a list of requirements for the system to be built.  

Optional partner or group work (without app)

  • Pupils can optionally sketch the possible system.
  • 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 gripping machine. The app guides them through the program in small steps.
Programming phase

Partner or group work

  • Pupils write the program for gesture control of the motors. The app guides them through the program step by step.
  • Individual intermediate steps are transferred to the RX controller and tested.
  • Help is provided in the app.
  • The complete program is transferred to the RX controller.
Experimentation and test phase

Partner or group work

  • The automatic gripper is put into operation and tested. It must only react to the gestures in front of the sensor.
  • Possible malfunctions in the functional sequence must be found and rectified.
  • Possible troubleshooting is possible using suggestions in the app
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 implemented using the app.

Discussion in plenary

  • Debriefing of the project in class.
  • Clarification of future application possibilities in everyday life (transfer of the topic to everyday life), recourse to the discussion in the introductory phase - e.g. locations such as fairgrounds and waiting areas as well as objects to be grabbed such as sweets and stuffed animals.

 

Information and notes

 

Methodical and didactic tips

 

Differentiation options

Faster pupils can be given the task of extending or shortening the playing time.
Motivational aspects

Pupils are familiar with grab machines from various locations in everyday life. Perhaps they have already operated such a gripper machine. Being on the “production side” instead of the “operator side” may fill them with pride.

Additional material

  • If available, pictures of free machines can be presented for the introduction to the topic.
  • If necessary, drawing media (paper, whiteboard or projection screen).

Building instructions

Circuit diagram

Functions of the model and their technical solutions

 

 

Functions of the Sensors/Actuators

 

 

Technical solution

 

Recording gestures
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Evaluating the signals on the gesture sensor

 

Light output

 

 

Illumination of the red LED


 

Material list
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Sensors

 

 

Function

 

1 RGB gesture sensor

 

 

Gesture recognition right/left and forwards/backwards
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2 buttons

 

 

Limit switches x- and y-axis

 

2 pulse buttons 

 

 

Rotation counter per axis (x/y) in 90° steps

 

 

 

 

 

 

 

 

 

 

 

Actuators

 

 

Function

 

 

1 motor x-axis

 

 

Forward / reverse travel

 

1 motor y-axis

 

 

Forward / reverse travel

 

1 LED

 

 

End of playing time display

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