If you have been to a concert lately, you may have experienced a wave of flashing helicopters coming down at the end. It's totally awesome and it's not rocket science to build them yourself.

This Instructable shows how to build the paper helicopter and the LED-blinking electronics.

Here's what you'll need for the paper helicopter:

1 sheet of stiff paper (we used a FedEx envelope)
Tape
Scissors or X-Acto knife
Printer (optional)

Here's what you'll need for the electronics

1 x Coin cell 3V (Jameco)
1 x Coin Cell Battery Holder (Digikey)
1 x NE555 General-purpose single bipolar timer (Jameco)
2 x Resistor 1Mohm (Jameco)
1 x Capacitor 470 nF (Jameco)
1 x NPN Transistor (Jameco)
1 x Big LED (diameter 10mm) (Jameco)
Wire & Wire strippers
Soldering Iron + Solder

Step 1: Cut Out the Paper Helicopter

Let's start by making the paper helicopter. We took apart ours to make the blueprint. You can download the .pdf and print it out, it fits on a "letter" size paper (8.5" x 11" or 215.9 mm x 279.4 mm).

All corners are nicely rounded so you won't cut yourself on the edges when it comes flying down.

In the last step you'll want to bend the wings, but save that for later.

Helicopter.pdf
Download

Step 2: Design the Electronics for the Blinking Led

There are many ways to make a LED blink but in this project we wanted it to be light, cheap, and doable with relatively common components.

To design the electronics we used 123D Circuits because it's free and has an awesome electronics simulator. We were able to design a circuit and make sure the LED blinked the right speed, then build the circuit based on our design.

We're using the ubiquitous 555 timer to create the on/off signal for the LED and a NPN transistor to make sure the LED is good and bright. The most basic version of this circuit uses two resistors and a capacitor, and instead of doing the math to figure out what values we needed to get the blinking right (1sec period), we used this online calculator: http://ve7sar.net/555calculator/timer.php

Check out the circuit below and press the "Start Simulation" button to see it blink!

You can also play with the circuit by going to the design page on 123D Circuits and duplicating it:
https://123d.circuits.io/circuits/1031569-led-paper-helicopter

Step 3: Create the Electronics

There are two way to approach this: fast but inefficient and efficient but slow.

Fast but messy
Pull out your soldering iron and just start soldering the leads of components together. This will get you quickly to a working circuit without having to wait for circuit boards to come in the mail, or for a mill to finish milling out your PCB. If you wanted to make a bunch of these you might prefer the next method...

Slower but clean
If you want to make a few and you can wait 2 weeks for PCBs to arrive: taking the file from 123D Circuits and having it manufactured is the way to go. This way you'll also have very clean, flat circuit boards without wires. Also it will make you look fabulous. Getting PCBs manufactured is as easy as a few clicks, we'll cover that later.

Onwards!

Step 4: Create the Electronics (fast But Messy)

Here's what you'll need for the electronics, you can buy everything at Jameco.com or places like RadioShack.

1 x Coin cell 3V (Jameco)
1 x Coin Cell Battery Holder (Digikey)
1 x NE555 General-purpose single bipolar timer (Jameco)
2 x Resistor 1Mohm (Jameco)
1 x Capacitor 470 nF (Jameco)
1 x NPN Transistor (Jameco)
1 x Big LED (diameter 10mm) (Jameco)
Wire & Wire strippers
Soldering Iron + Solder

Here's a video that shows how you can go from the digital electronics simulator on 123D Circuits to a breadboard and to the final soldered piece to be used in the helicopter.

Step 5: Create the Electronics (slower But Clean)

If you're not interested in making a PCB, you can skip this step.

Here's the list of component you need again with links to Jameco, where you can buy them.

1 x set of PCBs (sold in sets of 3 from OSHPark.com)
1 x Coin cell 3V (Jameco)
1 x Coin Cell Battery Holder (Digikey)
1 x NE555 General-purpose single bipolar timer (Jameco)
2 x Resistor 1Mohm (Jameco)
1 x Capacitor 470 nF (Jameco)
1 x NPN Transistor (Jameco)
1 x Big LED (diameter 11mm) (Jameco)

In 123D Circuits you can easily design a PCB based on a breadboard circuit, you can see what that looks like below. We ordered the boards today, and we'll update this section once they arrive.

To order PCBs from OSHPark.com follow these steps:

Visit the circuit (you can click this link)
Press the "Download Gerber" button, this will download the files as a .zip to your computer
Go to OSHPark.com, get started by uploading the Gerber zip file you got from 123D Circuits
Order the PCBs.