Winter 2012 Handcraft Classes

A great activity that will get kids out of the house during vacations (and away from computer games) is hunting for “treasure” with a metal detector. This winter, after some R&D work I finally worked out a design that would be easy enough for youngsters to make and use, but still powerful enough to find small things like coins.

(The technical details of it will be posted soon have been posted in a separate post here.)

Although the electronics work was not totally new to them (these students had made the morse key project earlier) it still required close supervision, so we only ran two small classes of three students each. About fifteen hours were needed to complete the project.

cutting and filing water pipe shafts


explaining the construction of the main parts


using a step drill to make holes for the pipe


taping the search coils after winding


completing the search coil assemblies


plastic cable ties were used so as to avoid having metal near the search coil

The electronic circuit boards were made by the popular “Manhattan Style”, whereby small pieces of copper circuit board are super-glued onto a blank base board. These provide insulated pads for soldering the components onto. It was made fairly large so that the whole layout would be visually easier to follow and to see what connected to where.

some explanation of the "Manhattan Style" of construction


soldering components onto the copper board


finding out about the color codes used on the resistors


checking with a meter to see if the color codes were right


some explanation of how the detector works


all of the detectors worked well and they could hardly wait to get outside to try them out

Jack was the first to make one. He completed his before the winter vacation. We took it and the prototype down to a local park one day and found some assorted pieces of rusty iron and an old dollar coin!

some of the “treasure” we found in the park

Early reported finds from the others include a soft drink can and “a bunch of small nails”.

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