Vending Machine Project

The purpose of the vending machine project is to build a motorized vending machine that recognizes when a “coin” is dropped into a slot and then dispenses “candy” bars when a selection is made. This project should be done by students who have had experience with Lego Logo programming.

Objectives

1. Using the Lego Logo kit and instruction booklet, correctly build the vending machine.
2. Correctly connect the vending machine to the Lego control box. Identify input and output objects. This project utilizes angle sensors as well as a light sensor.
3. Create a procedure that will allow the machine to vend.
4. Add extra sensors and reprogram to make the machine more realistic.

Materials List
Control Lab software
Vending machine building instructions
Lego Kit
Computer
Lego Control Box
Lego Logo Programming Book (helpful)
Computer Disks (if students are to save their work and they are not on a network)

Activity

Students work in pairs. (This can be self-selected or teacher selected.)
Students build the vending machine model by following the steps in the project booklet.
Students connect their vending machine to the control board.
Using what they know about lego logo, students experiment with creating a procedure that will make their machine vend.

Extending the Lesson

Have the students put additional touch sensors on their machine and write a program for that. Have the students write a number of procedures that nest into the main procedure.

Journal Writing and Research Questions

What problems did you have programming? How were you able to overcome these difficulties? Identify the differences between your vending machine and a real one. What additional parts/machinery would you need to create a machine that is more life-like?
Describe what you have learned from this project.