Crane Salvage Mission
The focus of the mission is Electromagnetism. Teams will be required to navigate a
small maze close to the pool edge to pick up 5 identical metal objects, one at a time
from the "sea floor" (bottom of the pool), using electromagnetism. The objects will
be dropped into a chute that leads to a lift basket. The Sea Perch must trigger a trip
panel to release the basket to the surface with a dumb weight. A SeaPerch team
member will retrieve the objects from the basket to end the mission.
We encourage teams to construct an electromagnet to retrieve the metal objects, but it
is not a requirement for completing the mission. Teams may choose their own
method to complete the mission. The electromagnet device does not count toward
your $20.00 budget.
Tips:
1. The Sea Perch must be capable of reversing back through the maze.
2. The Sea Perch must be able to release one metal object into the chute, return
to the maze and retrieve the remaining objects one at a time. Five trips total.
Metal Objects Specs:
1. Objects are sheet electrical steel.
2. Low, wide U-shape with square corners.
3. Dimensions of the shape 1" H x 3-3/8" W x 2" D
4. Weight - approximate weight 20 g based on a 14 mil / 0.35 mm thickness.
Mission Focus: Electromagnetism
Electromagnets are a type of magnet in which the magnetic field is produced by an
electric current. The magnetic field disappears when the current is turned off.
1. Electromagnets usually consist of a large number of closely spaced turns of
wire that create the magnetic field.
2. Wire turns are often wound around a magnetic core made from a
ferrimagnetic material such as iron.
3. The magnetic core concentrates the magnetic flux and makes a more
powerful magnet.
4. Main advantage of electromagnets over permanent magnets is the magnetic
field can be quickly changed by controlling the amount of electric current in
the winding
5. Unlike a permanent magnet that needs no power, an electromagnet requires
a continuous supply of current to maintain the magnetic field.
You can easily construct an electromagnet out of an AC step-down transformer. It has several benefits: 1) It's a commercial part that doesn't require sourcing several materials.
2) The coils are pre-made/wound.
3) There are no capacitors which could discharge on unsuspecting hands
4) The soft iron core can easily be modified to convert this from a transformer into
an EM. The internals were changed (core was broken apart and re-configured, coils were
connected in series) and was powered using a standard SP battery (12 VDC, 7-8 Ah). Check out this Youtube video on how to build an EM.
"How to build a useful electromagnet with two small transformers found
around the house" - https://www.youtube.com/watch?v=oEvC-1DUQRg ).