Make a 3 inches (7.5) cm coil in diameter
Electronic
Takes 50 feet of awg wires 22

I chose a box of vitamins or omega 3 that had exactly the required size.

Drill four holes in the tablet box as shown in fig. below. These holes will fix the ends of the coil.

Then take the 0.02 inch (0.6 mm) diameter rigid wire. If you choose a magnet wire with thin insulation, the coils of the coil will be closer and the coil a little more efficient. But a regular wire with vinyl insulation will also do the trick and will be easier to handle.

Start by removing the first 6 inches (15 cm) of the insulation at the end of the wire. Keep about 47 inches (1.20 m) of insulated wire and cut the insulation at this location with the wire strippers, being careful not to cut the wire itself. Remove the insulation with the nails, leaving about 0.5 inch (1.25 cm) of bare wire, as in the figure.

Then fold it in the center and form a loop.

You have created an intermediate tap, which is a point where you can use part of the coil after rolling it up. You will need another 11 intermediate sockets, all spaced about 0.5 inch (1.2 m) apart (if the diameter of the box you are using as the core of the reel is not 7.5 cm, multiply the diameter by 16 to get the desired spacing of intermediate inlets).

Once the 12 intermediate sockets have been created, cut the wire and expose 6 inches (15 cm) of this end. Then fold the U-shaped end about 0.5 inch (1.25 cm) in diameter so that it can be inserted through the two drilled holes at the top or bottom of the box. Pass the thread, then loop to create a secure anchor point.

Then wrap the rest of the wire around the box, pulling it firmly so that the windings stay close to each other. When you have reached the end of the wire, insert it through the other two holes to secure it as shown.

Crystal radio
with a Germanium diode 1N34 or 1N60

Note: The plug to earth is done by connecting a wire to a cold water pipe. The pipes are deep enough in the ground and connected to the grounds of the electrical system.