One of the features of the Wizarding World of Harry Potter at Universal Studios theme park is “Interactive Wands” where you are able to move a special “Interactive Wand” to control various objects around the park. This feature is a lot of fun, and is where the original idea for this project came from. My son requested a Harry Potter themed birthday party for his most recent birthday, which is the event that caused me to actually create this project.
The interactive wand feature at the Wizarding World of Harry Potter seems to work by having IR lights that shine towards you, having that light reflect off your wand tip, and using an IR camera to to track the reflected light / the movement of the wand. This movement data is then processed by something behind the scenes and if that movement data corresponds to the defined spell the action is performed.
My version of this system consists of three parts: The Wand, The IR Light / Camera, and the processing software. I’ll write a post for each part. This one will cover the wand.
You can actually buy the interactive Harry Potter wands directly from The Universal Store. They look great and will work with my system. However, they are expensive. I wanted to give each of the kids attending the birthday party a wand, so obviously this option wouldn’t work.
I ended up finding a fantastic STL of Harry’s wand on Thingiverse by user low_seb. I scaled the original model up to 11 inches vertically (to match Harry’s true wand size). For my use I needed a wand a little thicker, so I scaled it to be slightly thicker in the X and Y dimensions than the original model. (I did this this so the next step wouldn’t throw off proportions significantly.) Then I modified the upper shaft in Fusion 360 to match the diameter of a standard hole punch (I used 7.5 mm) and ended the shaft with a flat surface. This was so the reflective surface could easily be hole punched and added to the end of the wand.
I printed the modified wand vertically on my 3D printer without issue. I’ve published the STL on Thingiverse for you to download here.
For a reflective surface I tried many different possibilities: reflective paint, IR reflective tape, and white micro prismatic reflective tape. The pictures below show the wands as seen with a regular camera, an IR camera close up, and an IR camera at a distance of around 10 feet.
What ended up working the best was the white reflective tape. The IR reflective tape was unique because it allowed the tip of the wand to be flat black instead of glossy white, but in the end I chose the white reflective tape for it’s superior performance. It was also cheaper, which was an added bonus since everyone at the party got to take home a wand.
In part 2 I discuss the IR light / camera system for this project.