I will show you how to make two different gun sights out of cardboard.
You will need:
2 1.5v cell batteries
a piece of plastic you can cut it out from a plastic soda bottle or a fruit container
Step 1: Building the Box and Circuit
First, draw this onto a piece of cardboard, cut it out, and fold it. You should now have a little box.
Now build the circuit.
Now you need a piece of clear plastic. YOu can get it from a plastic bottle a container of fruit or a CD case. Using a knife or a paperclip, scratch a reticle or a square into the plastic.
Step 2: Putting It Together
Hot glue the plastic at one end of the box and hot glue the circuit into the box. Angle the LED so that it is pointing towards the plastic. Cut a whole in the side to stick the switch out through. Glue that in place and glue all of the sides of the box together.
Next cut out 2 of the shapes in image 3 and glue them to the opposite sides of the box.
Then glue another clear peice of plastic on the front of the thing and a peice of cardboard on top of this.
Step 3: Paint It
Use black acrylic paint to color it. Cover the plastic with tape to avoid coloring it.
To attach it to an airsoft gun either tape it on or hot glue or tape it to a removable rail.
Step 4: Red Dot Sight
To make a red dot sight, make a whole in the piece of plastic using an awl and glue an led into it. That is pretty much the only difference.
Step 5: Conclusion
I like the red dot more than the holographic sight because it works betters in the light. I think it my gun is more accurate without the sight because its about 3 inches higher than the actual gun's sights but if i put the hop up on it is fairly accurate and is quicker to aim with. I think the holographic sight looks cooler.
I might add another step with some other easy to make gun accesseries to this instructable such as a verticle handle and some other stuff.
If you make one please post a picture.