How to Build an Automated Arduino-Controlled Ouija Board

In this tutorial, I'll show you how you can create a spooky Ouija board or chess board on which the pieces move by themselves - great for an Escape Room prop!
It uses an Arduino to send G-Code messages to a CNC controller running GRBL software, which moves a magnetic head controlled by stepper motors on an aluminium frame.

You can build the mechanics yourself using the following hardware, which allows to choose the exact dimensions of the frame (e.g. to be installed under an existing table):
2040 Aluminium Extrusion uk.banggood.com/custlink/KKDyVJ8555
GT2 Timing Pulley / Belt uk.banggood.com/custlink/vKvRVrIFH8
NEMA17 Stepper Motors uk.banggood.com/custlink/mvKYtWIHHn
CNC Shield uk.banggood.com/custlink/K3vYtJZ5Ih

Or, you may find it simpler to just buy a complete ready-to-assemble kit containing all the above + necessary screws etc:
Eleksmaker A3 Machine banggood.com/custlink/mv3EVCrS8T

The board on the CNC controller itself runs "GRBL" software. It probably already come pre-installed with your CNC shield, but if not you can download from github.com/gnea/grbl and follow the comprehensive instructions at github.com/gnea/grbl/wiki/Compiling-Grbl to install it. Note that you might have to change the baud rate on line 42 of config.h to match the baudrate defined by the AltSoftSerial connection in CNCController.ino, e.g.:
#define BAUD_RATE 9600
You can view a full list of commands at github.com/gnea/grbl/wiki/Grbl-v1.1-Commands
The most important ones to note are:
- G90 (Use absolute coordinate values)
- G91 (Use relative/incremental coordinate values)
- $J= (Issue a "jog" command)
- G01 X... Y... F... (Linear movement to specified X/Y coordinates at specified F rate)
- G04 P... ("Dwell" - i.e. pause for specified number of seconds)

Timings
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00:00-02:58 Introduction and Demonstration
02:59-05:04 Behind-the-Scenes
05:05-09:24 Wiring and Components
09:25-38:24 Arduino Code
38:25-42:56 Wrapup

Code & Wiring Downloads
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If you'd like to download the code and other resources used in this project, and support me to make more video tutorials explaining how to use tech in escape rooms and other playful settings, please check out my Patreon at patreon.com/playfultech, where you can also find code downloads, wiring diagrams, and additional resources for all my other tech projects.