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An alligator clip sensor is simple to make and very flexible - you'll find many ways to use it.

Alligator Clip Sensor for RCX

I've been wishing there was an easy way to make an alligator clip sensor for RCX. Then I finally looked at an RCX connector closely, and realized all I needed was a regular Lego block and some copper tape, and voila! - Margaret
stuff you need
  • Copper tape
  • 2 x 2 Lego brick
  • Alligator clips

You can find copper foil tape at art supply and at garden supply stores. The copper tape has a peel-off backing.

Cut two pieces of copper foil about 3 inches long.

Peel back about an inch of the backing.

Stick the foil on the inside of the block, near a corner of the block. (Take a look at a Lego connector and see where the shiny metal bits are.)

Use a dull pencil or a toothpick to reach inside the Lego and press down the copper tape.

Peel more of the paper off the tape, and smooth it up around the side of the Lego.

Place the second piece of tape in the opposite inside corner of the Lego, and smooth it up around the side of the Lego.

The tape will stick up above the top of the Lego. Fold the tape over onto itself (the sticky part inside) to make two copper "ears."
Clip one end of your alligator clips onto the copper ears.
Then, write a program for your RCX to respond to the alligator clip sensor.
Watch the sensor value change as you touch the alligator clips to different materials.
What else
Learn to make copper sensors.
Read what Margaret wrote about her interactive storytelling idea.
Will food conduct electricity? Read about an activity that combines food and Crickets.

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