Observer is a craft able block that can be used with redstone circuitry. Observer has an input face and an output face. When there is a change on the input face, the observer emits a redstone signal toward its output face for a short period of time.
To make an observer, you will need Nether Quartz, Red Stone and Cobble stones. Please follow the following steps to make an Observer.
In order to make an observer, the basic item you will need to get is nether quartz. For that, you will need to go into the nether and get at least one nether quartz using your iron pickaxe.
The next item that you will have to find and get is the red stone block. Go to the mining area down stairs and get at least two red stone blocks.
After that, the next required item that you will need to get is cobblestone. You have to get at least six Cobble stones. Use your iron pickaxe to get these stones.
Now you can make an observer by using the crafting table. Go to crafting table and open up 3*3 crafting grid to add six cobblestones, two red stones and one nether quartz by following the pattern shown below. You will get an observer in the right-side box to the crafting table. Add this item in your “ready to use” stock.