Instruction Guide: EV3 - Faraday Golfing Machine

Submitted by Randy Steele on 14 October, 2013 - 07:38

In this Lesson we have 2 Primary Instruction Resources:

1) The Faraday Golf Tournament PPT

2) The LEGO Digital Designer files of the building examples

NOTE: The link above is to the latest version of LDD. If you have problems with this version, try this link to the older version 9 - this is no longer supported/updated, but has all the EV3 parts built in.

If you wish to see only the parts in your EV3 kit in the palette, select your theme to be "LEGO MINDSTORMS" (under "View" on the top menu bar) and then select your desired kit from the "Filter bricks by boxes" icon (at the bottom of the Bricks Palette).

Resource 1:

Use this Faraday Golf Tournament PPT to explain the challenge and its scientific underpinnings.

Slide 1

The illustration shows the inside of the large and medium EV3 motors with their internally gearing.
These images and photo show the round metal motor that drives the gears.
Have students connect two motors directly together using a wire:
- The second motor will act as a generator and creating an electric current that cause the other motor to move. The is the Faraday Principle at work named after Michael Faraday.
In the case of the Golfing Attachment motor, electrical energy (current in the wires) is converted into kinetic energy (motion)
- The Electromagnet link show a photo and illustration of a simple electromagnet using a battery, loops of wire and an iron nail:
  - Ask students if they have built an electromagnet like this in early science classes.
- The Motor Animation link shows a video animation of how motor works. An outer fixed magnet (blue) creates a constant magnetic filed between its north and south poles. An inner rotating electromagnet (green battery, yellow loop of wire) also produces a magnet filed which turns the loop in an attempt to align with the N/S field of the fixed magnet. However, just when the fields are nearly aligned, the direction of the current through the loop reverses (red line on yellow loop base), so the electromagnet field also reverse and rotating loop attempts to align in the opposite direction. By constantly switching the direction of the current every half-turn, the motor turns constantly as it "chases" the fixed magnet field.

Slide 2

Students begin by building a golf club attachment using either a medium or large motor.
- Slide shows two examples. Students are encouraged to create their own. The Lego Digital Designer .lxf files for these 2 examples are attached to the Primary Instructions Material.
They will then need to build a self-supporting frame/structure to support this attachment with a size/height sufficient to allow it to strike a light weight ball on a tee
- have student recall the previous lesson on building strong structures
- be creative deciding on what will be your ball and tee...though the ball should be very light weight.

Slide 3

Michael Faraday discovered that the above process could be reversed.
In the case of the remote control generator, Faraday's Law converts kinetic energy (motion) into electrical energy (current)
- The Faraday's Law Animation link goes to an interactive animation site. The user can click on the bar magnet and move it through the loops of wire. When this happens, a current is generated in the wire as can be seen by the meter moving and the lamp illuminating.
  - the lamp will illuminate when the magnet is move in either direction, but the mete shows the current actually switching direction with the movement
  - note too, that the intensity of the light and the level shown on the meter increase with the speed at which the magnet is moved through the loop
- The Motor vs Generator Animation link is a video which shows the similarities and differences between electrical motors and generators. Here again, we have and outer fixed magnet and an inner rotating electromagnet. In the case of the generator however, the mechanical energy is input (wind in the case of the video, but is could also be a hand crank, etc.) on the rotating electromagnet and electricity is produced in the wire loop.

Slide 4

Finally, they will need to build a remote control to operate their Golfing Machine. This control will take advantage of Faraday's Law to eliminate the need for a batteries.
The example shown in the PowerPoint is a safe remote control.The student design should attach to the motor hub at multiple points similar to the example shown.
IMPORTANT Note: The EV3 internal motor gears appear to be weaker the the NXT gears. NXT golfing machines were able to use short beams as levers to create more torque, but this has caused damage to EV3 motors. See photo on slide. As a result EV3 remote controls should use no levers of any kind. Consequently, the EV3 golf challenge you design should more resemble a mini golf course than the NXT style driving range. The challenge should be about finesse and control, not hitting the ball hard.

Resource 2:

The LEGO Digital Designer files provide the building examples shown in this lesson PowerPoint. If you need to install LEGO Digital Designer, see this page. Once the .lxf file is opened in LDD, select ""View", then "Building Guide Mode (F7)" to get step-by-step instructions to build the model.

Note: when attaching an axle to the Medium Motor, it must be inserted until it noticeably "clicks" to lock into place.

Faraday Golf Tournament Rules

A Task Assignment sheet for this challenge is included in the Summative Assessment.
The scoring in this sheet gives most credit for successfully building a Faraday Golfing machine that meets all building requirements and can hit the ball off the tee - bonus points are given for scoring on the course.