993. Physical Fabrication

Totally Tubular

I like working with the shotgun microphone during Sound & Video projects. It is useful because it records mostly in one direction, and has a bit of length to it, so you don’t have to get close to the source of the sound. It records mostly these areas:

shotgun microphone polar diagram (where it looks for sound)

For me, the shotgun microphone really fun to hold and point in various directions …and served as inspiration for the totally tubular
Shotgun Flashlight!!

The blue light coming out looks like this:





MATERIALS: the materials used to make this included:

A poster tube, a strip of cardboard, scissors, and (optional) a ruler
A standard 9V battery and clip connector
Some blue LEDs (5 or more)
copper wire – at least 12 inches







I conceptualized the following design, using a series circuit to give all LEDs equal voltage. Note the resistor in the circuit as well! I lost 8 LEDs in the blink of an eye without one 🙁


I cut the strip of cardboard into a thin slice that fit into the tube, then put down two ‘rails’ of copper wire, and attached the 9V clip connect and resistor with duct tape.

…then added the LEDs in a similar fashion. Remember that the D in LED stands for diode, and they must be aligned with the polarity (+ / – ) of the circuit (the longer stem is the + input).


I tested the connection as they were attached making sure the LEDs were all working. Next, I glued the battery to the cap of the poster tube like so:



Finally, I taped the light strip to the inside of the tube:







When the battery and connector are attached, you should see LIGHT!


Now that the flashlight worked, I decide to decorate it with the swirls you see in the glamour shots. To do this I painted it black, laid down some painters tape in a pattern, then painted it with shiny sliver paint, and finally remove the painters tape.

paint it black
use painters tape
add a coat and remove the paint

One reply on “Totally Tubular”

Good work. Using the cardboard tube for the housing is a great idea. It’s light, cheap, and comes with caps that fit the tube already.

I think soldering the circuit would help a lot for this project. The wiring would more secure for one thing, but I think the cardboard would not be necessary if stiff wires were soldered to the LEDs. It would probably all ow more light as well (no cardboard blocking it).

I wonder if all of the circuit could be mounted to the tube cap, that would make repairs much easier.

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