An inexpensive way to add color to any ferromagnetic surface in the neighborhood is the use of LED throwies. A lithium battery, a 10mm diffused LED, and rare earth magnets taped together comprise a Throwie. It can be used to impress your friends and city officials by throwing it up high and in quantity.

This project is known as the night writer in which the functionality of LED throwies is extended by allowing a writer to catch a tag in lights. The 12-inch letters are written 25 feet in the air by taking some basic LED throwies that consist of a magnet, LED, and a battery, which is placed into a stencil. The stencil is positioned on a pole or iron and any desired message can be written and be stuck on any magnetic surface as shown in the image below.

The image below shows the required materials which include a preferably black foam core, clay, epoxy, 15-foot telescoping pole, shrink tube or electrical tape, a few hundred throwies, and paint edger attachment.

The first step is to cut a 10-inch wide strip of the 1/2-inch and 3/16-inch foam core. Whatever will be written will determine the length of the strips. 3.75 inches in length are added for each letter. As shown below, a 1.25-inch square grid on the 1/2-inch foam core is graphed out and a 1/3-inch diameter circle at the intersections is made. Using short cuts tangent to the circle, a hole is cut in the foam.

The epoxy is used to glue the 1/2-inch and 3/16-inch foam core strips together once all the holes are cut into the 1/2-inch foam core. On the back of the night writer, the paint edger attachment is fixed using the epoxy as shown below. The painter attachment can be screwed onto the telescoping pole for loading the night writer once the epoxy has set up.

To catch the tag, sufficient LED throwies should be made. The original throwie design can be modified by adding shrink tube or electrical tape to the leads of the LED. The shrink tube can be reduced by using a lighter or hair dryer as shown below. Around 50 throwies will be consumed to write a 4-letter word on average.

For the LED on the throwie to be pointing perpendicular and opposite the face of the throwie with the magnet, bending is done. A small ball of clay is added to the throwie face opposite the magnet as shown below. When loading the word into the night writer, the text should be reversed and mirrored. To see what the word would look like when loaded correctly into the night writer, a javascript application can be used.

More of the LED throwies campaign can be seen in the following images.