When you plug the alligator clip sensor into the Cricket, the Cricket measures the resistance between the two wires.
Alligator Clip Sensors
This is a very simple sensor: it's just a pair of wires with alligator clips on the ends. Try attaching it to all sorts of things--for example, cans, sponges, ice. - Keith
To make your own alligator clip sensor, you'll need:
Coated wire
Wire clippers
Tape
Scrap of cardboard
A Cricket (to plug your sensor into)
To make the part that plugs into the Cricket's sensor port, cut two pieces of wire about 10 inches (25 cm) long. Use the wire strippers to strip the plastic coating off one end of each of the wires, exposing about 1 inch (2.5 cm) of wire.
Cut a small piece of cardboard to hold the wires that will plug into the sensor port. Make two marks on the cardboard that show you where the
Attach the wires to the cardboard. Line up one end of each piece of wire with a mark on the cardboard, leaving about 1/2 inch of bare wire extending beyond the cardboard.
Wrap tape around the cardboard to hold the wires in place.
Next, strip the plastic coating off of the loose ends of each wire, exposing about 3 inches (7.5 cm) of wire. Clip an alligator clip to the end of each of the wires.
Your alligator clip sensor is ready to use!
Plug your alligator clip sensor into the sensor port of the Cricket.
Here's a sample program that continuously displays the value of the sensore.
Try touching the wires to each other and to other materials, like playdoh or ice or a slice of fruit. Or hold the wires in your hands. What do you notice?