How to Build an Electric Eye
Experimenting with electricity has always been a delight for many people. With the building of an electric eye, it will not only be exciting but it can be used for various purposes too. One can also gather knowledge through this. From a bell to a motor, it may be used for various things. An electric eye can be built easily.
Step 1: A piece of mica has to be taken, and it has to be notched with many teeth. Small holes need to be drilled in the corner.
Step 2: A no.18 wire has to be used and the end has to be tied to the holes in the mica. It is correct that if ten turns are made, the notches have to be used at the top as well as the bottom edges. This has to be pulled tight, and the opposite end where it was tied first has to be tied with the end of the wire in the holes. The second wire can also be done in this manner.
Step 3: The windings have to be tested, and if they touch then the lamp will be lit.
Step 4: This will denote that the cell is ready, and the selenium has to be used next. A gas flame, a sand bath and a thermometer as well as a stand is needed for this. The thermometer has to be put in the sand bath, and the cell has to be laid on that too. The cell has to be heated this way, until the cell melts the selenium when it is touched. The melting element should be used to cover the cell, and it should fill the wires. All the lumps should be smoothened out. The temperature to be maintained will be 428 degrees.
Step 5: The cell has to be cooled slightly now, after it is filled. The temperature has to be lowered and the cell must be placed on the sand bath cover and heated slowly. The selenium will get crystallized with this.
Step 6: Once it is gray, the temperature must be watched to see if there is any melting. The selenium edges will turn black. The cell must be removed at this stage, the temperature decreased and the cell must be replaced.
Step 7: This has to be repeated, then the cell can be covered with a glass cover. It has to be in the heat for three hours. Over the next hour, the temperature can be reduced and completely cut out. It can be covered with a asbestos sheet or a cloth until the cell turns cold.
Step 8: All electrical shorts must be tested for, and only then mounted. A wooden box needs to be made for the cell and must be closed. You can adjust the relay points so that the current flow does not get cut out if the slide is closed. A rheostat can be used to control the flow of current as you want it.