If time is an issue, then this Minion costume is the way to go because you are really only making one piece of the costume! After that, we sprayed painted the whole thing white as a base coat, then sprayed painted it yellow.

Glue the cap to the tube. Use lots of glue, and one at a time. The cap and tube need to be pressed together while the glue dries. For this, I used some speaker wire and wrapped it around tight. If using a separate supply for the LEDs (a boost converter, for example), at least a 100uF should be used.This code defines the pins for each function. The LED pins are the pins that drive the output MOSFETs. The switch pins are the pins of each button, and the potentiomiter.

The controls for the traffic light costume are pretty simple - just four buttons and a potentiometer (pot). This could be simplified even more, with just a potentiometer, if preferred. I'll be working with my 8-year-old on a costume that she'd like to build for herself: a traffic light with signal lights that light in the usual green > (brief) yellow > red sequence. We were thinking a box over her torso with lights, maybe 5"-7" in diameter, controlled by an Arduino. Having a fairly accessible on-off switch and simple battery power would be ideal.Piranha, Flat Top, and Straw Hat LEDs all have one thing in common: they all have a fairly large throw angle. Piranha have the largest, followed by straw hat and then flat top. A large angle of throw is important to get a good, even light. If using these types of LEDs, you need to use series resistors to limit current. Use an online calculator to get a current of about 20-30mA. For the red and orange LEDs, two (with a forward voltage of about 2-2.2V each) can be used in series per one resistor. For the green (with a forward voltage of about 3.2V each) one can be used in series with a resistor. This is assuming a 5V supply. Any momentary button will do for the controls. You may, however, find some have better or worse switch characteristics. Some buttons may 'bounce', and will activate functions more than once, even if the button was only pressed once. This is easily fixed in software by increasing the "debounce delay". When I made the first version of the traffic light costume, about 3 years ago, it was mainly made out of cardboard and duct tape! Since then, 3D printing as become common, and much more affordable. My second version is about 50% 3D printed. It is much more durable, and can now even stand up to some light rain.