The previous page discussed the dimensions of a robot contest arena. On this page, we specifically discuss how to cut out and assemble the polarized light beacon window in the scoring nest.
The nest has two side panels and the rear panel. The rear panel has a small window for emitting polarized light.
Robot egg hunt nest.
The front of the nest has a short lip to prevent eggs from easily rolling out on their own. The floor, sides, and rear of the nest are all white.
Begin by cutting a board to a length of 3 feet using a table saw or power saw. To cut out the beacon window, put the board on sawhorses or raised blocks.
Use saw horses or concrete blocks.
Mark the beacon window location with a ruler or a paper template. Drill starting holes in the corners of the window using a 3/8 inch diameter drill. This makes it easy to drop in the saw blade of a jigsaw or other similar power tool.
Drilling corner holes and then cutting window with jig saw.
You don’t need to be too precise cutting out the window, as the polarizing film and window frame covers some sloppiness.
Make a window frame out of poster board, cardboard, plastic, or metal. Tape the frame to the board and mark holes. Drill the holes with a 1/8 inch diameter drill bit if you choose to use #4-40 machine screws to fasten the frame. Obviously, you can use other sizes or wood screws if you prefer.
Drilling frame holes while taped in place.
You can tape both the frame and the polarizing film to the window and drill holes straight through in one pass. Or, if you already drilled holes in the previous step, you can drill a hole, insert a screw, drill another hole, insert another screw, and so on. The screws hold the frame and film in place during drilling of subsequent holes. The film can be awfully slippery and difficult to drill without it moving.
Tape polarizing film drill hole insert screw repeat.
Important: Remember to insert the polarizing film in a horizontal orientation for one nest, and a vertical orientation for the other nest. You don’t want two nests emitting identical polarity signals, or the robots won’t be able to find their home.
You can use polarized sunglass lenses to determine the orientation of polarizing film.
Indicate the excess polarizing film by tracing around the frame with a permanent marker.
Marking edges of polarizing film before trimming.
Remove the frame, film, and screws. Then, cut away the excess film.
Paint the nest boards white and let them dry completely.
Reattach the frame, film, and screws. This is one of the reasons I chose to use removable machine screws (with nuts on the opposite side) rather than wood screws. Future maintenance is easier with machine screws if something should happen to the polarizing film, such as puncture damage or melting due to a hot light source.
Speaking of which, the light source is placed behind the nest, facing out through the window with the polarized film. Be sure to allow plenty of air circulation to keep the light source cool.
Now that the rear of the next is complete, we are ready to attach the sides boards.
