some glue (I prefer strong geltype, dries in 24hrs)
a cr2032 3v button battery
some flux / rosin will help soldering on the metal of the pin
a piece of putty rubber
and of course a soldering iron with some solder, and other tools….
The copper tape on the legs of the peg conducts electricity from the battery to the LED. Notice that I use the metal of the spring to conduct the current too, by putting the copper tape in one slot under the metal spring. The battery has a positive and a negative side. Often the positive side is marked with a ‘+’ sign. The LED also has a positive leg (long) and negative leg (short). By sliding the battery in the mouth of the pin it powers the LED. But the tilt sensor must be upright to conduct the power, it acts as a switch. Once placed on the fridge you can turn the LED off by turning the clothes peg upside down.