Building Mercy's Caduseus staff (Overwatch)

When I first saw the the reveal trailer for Overwatch I knew I had to cosplay Mercy. And I couldn't do that with out a mechanical Caduceus Staff :D My goal was to have it spin clockwise and glow yellow and counter clockwise and glow blue as it does in the trailer. Here's the tutorials for the wings and the overall costume. 

The build itself doesn't have that many new points, you have all seen worbla work on my page before. But the electronics in this project I must say that I love. Might seem simple at first, but it took some thinking, which I gladly share with you. 

So the first half of this tutorial will be about the circuit and the second about the actual build and assembly. I have included small videos for each step, but in the end of the tutorial there is a full video showing everything. 

You might know a lot about circuitry or maybe nothing at all. Hopefully I can explain this in a way so you can make use of this feature.  

Basic electronics  - how to make a led glow?
Very simple said, you need a battery and a led (and a resistor if the voltage is too high for the led). 

To make it more practical you can add a switch. You should note that an LED will only light up if the current goes the right way, meaning from the positive of the battery to the positive of the LED. You can read more about LEDs on wikipedia.

Photo: Wikipedia

How to light up two colors not at the same time, but on one circuit?
For this you need a two way switch, so when it is in position 1 the current flows thought one circuit and in position 2 it flows thought the other. I think of it like train changing tracks :)

I also did this for my portal gun when I first built it. 

How to make something spin?
For this you first need a small EL motor, if you put power to it it will spin and if you reverse the power direction it will spin the other way. 

But how to make it spin both ways without flipping the battery?
For this you need a switch that can turn the current flow for you, a normal three way switch won't do that. You need a DPDT switch. 

This is a rough sketch of my diagram, showing one battery, one switch, one el motor and yellow and blue lights. For my actual circuit the led will be set in parallel as it draws less voltage. 
For this test I have only added two blue lights, one to glow when it spins clockwise and the other to glow as it spins counter clockwise. For my final circuit I added two blue/yellow for the front, one blue/yellow for the symbols indicating if the staff is healing or boosting, and two yellow (only) for a "on-indicator" lights that glows yellow for both options. 

And here's my first demo after getting the parts together. 

To make it light out through the tip I made the base of the tip out of transparent plastic. After building the staff I found this switch over at adafruit that could have helped a lot :)

Then the build
Okey, I now know hot to make it spin and glow, let's build the body of the staff to have something to put the electronics in ;)

To be able to transport my staff I divided into three using soda bottle caps as my was of attaching them together again. The staff main body is made out of a pvc pipe with details of foam and worbla wrapped over. 

The light up control panel with the healing/damage boost symbols. 

All the electronics were embedded in the first third of the staff. 

To make the front part spin I had to make sure it was as light weight as possible. And I needed three identical parts for the "wings". Therefore I made a base in clay (with a core out of tin foil).

Then I wrapped worbla around the mold, peeled it off and got a hollow shape. Did this two more times and I had all three. Then very carefully I added the underside. 

The "wings" are attached with 3 mm bolts so they can be takes off for easier transportation. 

Now we are ready for painting, all parts were spray painted dark grey and white. 

Adding more shading and details. The battery can be changed from the first screw joint. 

Final staff

If you are interested here's the full tutorial video.