Building a Marauder’s Map

Christopher Cartland
2 min readOct 31, 2020

We built an interactive Marauder’s Map for our 2019 Halloween party.

Animation of an indoor map with footsteps walking around between rooms. Some of the footsteps are labeled with names.
Animated footsteps walk around an indoor map

Features of the Map

  • Walking footsteps
  • Magic wands
  • Name tags that appear when you use the magic wand

Live Demo

Tap the magic wand to see the character appear on the screen!

Screencast Demo

This screencast shows the Marauder’s Map animations in detail.

Android TV + Picture Frames

We used an Android TV device for the largest version of the map. Extra Android devices were put into picture frames so that we could have maps in multiple rooms in the house.

Android NFC reader + Map viewer

Open the app in order to view the map, or use a phone as an NFC tag reader. When an NFC magic wand taps any of the NFC readers, all of the maps update with the name of the character.

“Reset” NFC tag for fast development

One of the NFC tags resets all of the maps. This enabled rapid development because we could deploy new versions of the map without touching all the Android devices. We used this during our 2019 Halloween party after a guest showed up in a Hogwarts student costume. In just a few minutes, we gave them a wand, added their character to the map, and reset all of the maps on the Android devices so that the new character would appear.

Hogwarts Halloween Party

The Marauder’s Map project was a feature of our Hogwarts Halloween party in 2019. Look for floating candles & pumpkins, a portrait of Dumbledore, Harry’s room under the stairs, the Mirror of Erised, the four houses of Hogwarts, framed posters from the books, magic wands, and the Marauder’s Map.

Source code on GitHub

The source code for the web app and Android apps is available on GitHub. https://github.com/cartland/Marauder

Mischief Managed!

7 wands pointed at each other so that the tips of the wands almost touch, held by people mostly out of frame
Seven marauders holding magic wands

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