Magnetically-Activated Escape Room Prop Tutorial

Magnetic sensors are one of the most commonly-used inputs in escape room tech puzzles. Whether it's returning a dragon's egg to a nest, placing a missing book back in the correct position on a shelf, or moving a chesspiece to a certain square on a chessboard, a simple magnet embedded in almost any portable prop component can be detected by a microprocessor such as an Arduino to trigger a response - activating a relay, opening a maglock, or firing a smoke machine. Like many other ER sensors, if done well, this simple technology can create "magic" as far as the player is concerned!
There are two common types of magnetic sensors - Hall sensors, and reed switches, but there are many varieties with different properties and characteristics, so which should you choose? In this video, I'll show you some of the important properties of a component datasheet to look out for, and give a practical demonstration of a variety of common readily-available magnetic sensors - the Honeywell SS49E, Allegro A3144, A1324, and A1389 - comparing their output and sensitivity to different magnets.
Based on an analysis of those findings, I'll then show you how to write the Arduino code for an all-purpose magnetic prop controller which automatically calibrates to its environment on startup, has adjustable sensitivity, and fires separate triggers to respond to either a north pole or south pole of a magnet.
Timings
---
00:00 - 01:23 Introduction
01:24 - 04:20 Selecting a magnet
04:21 - 04:45 Selecting a magnetic sensor
04:46 - 05:47 -Reed switches
05:48 - 13:42 -Hall sensors (SS49E, A1324, A1389, A3144)
13:43 - 14:32 Practical sensor comparison
14:33 - 18:49 -Wiring
18:50 - 19:51 -Arduino code
19:52 - 24:15 -Live demo
24:16 - 25:55 -Analysis of findings
25:56 - 29:27 Creating a magnetically-activated ER prop controller
29:28 - 41:11 -Arduino code
41:12 - 43:12 -Live demo
43:13 - 44:08 Wrapup
For more resources on this, or any of my other escape room puzzle projects, please check out my Patreon at / 26349661

[@toschrama]

`My choicd would be the Reed switch as it does not need a arduino but can be an easy switch. Nice to see a prop build again.

[@PlayfulTechnology]

Neither a reed switch or Hall sensor *needs* the Arduino - you can use the output from either to switch a transistor which activates/deactivates power to a maglock directly, say. The advantage of having the Arduino is that it allows for calibration and easy customisation of the puzzle behaviour logic through code (imagine if you wanted players to hold the magnet in place for 3 seconds before activating), as well as allowing remote override should the sensor fail, or integation with a room controller that can monitor/reset puzzle state etc.

[@elie3423]

your channel is a hidden gem. wow

[@aaronwhitehead5959]

You are awesome and my inspiration for building escape room puzzles!

[@positiveground2995]

Great video!! Thanks so much for the final tip (Multiple magnets w different orientations)!! Great less expensive solution than RFID for the more simple end of the object identification problem!!

[@familiasalvaje4339]

Thank you friend

[@Wranorn]

Loving your content. I think you have that backwards between SS49E and A1324 sensivity. Respectively, 1.4 mv/Gauss and 5.0mv/Gauss,... Given a supply voltage of 200mv (For simplicity's sake), the SS49E would have 142 (200/1.4) segments of measurement and A1324 would have 40 (200/5). Usually the more segments, the higher the sensitivity, or did I miss something?

[@manuosiris4291]

Que sensor es el que usas el último?

[@soundpreacher]

Can we get a link to that 3D printed mount?

[@duncanx99]

Is there a standard for the 'screw on' magnets, in terms of which face is the North pole? How do spherical magnets work - is one pole 'buried in the centre of the sphere'?

[@PlayfulTechnology]

Great question. AFAIK, there's no real "standard" for the screw-on magnets, and it's not something I've ever seen stated on a product description either, so you'll probably just have to test empirically on a particular batch (and hope that, at the very least, all the magnets from the same batch are the same!). Spherical magnets are divided into two hemispheres - much like the Earth itself - with a North pole and a South pole at opposite ends.

[@duncanx99]

@@PlayfulTechnology Thanks I have some spherical magnets on order (to drop through an aluminium tube - to amaze a five year old Peruvian with 'techie magic'. We'll work up to the explanation when she's a bit older.

[@leonidtyan6805]

Hi, how we can to contact to your regarding affiliation with us?

[@moomoo2214]

Hey I recently discovered your channel and I instantly LOVED your content. You do a great job of making your extremely cool ideas 😊!! Could you just make your videos a little shorter with more sort of abstracted, less technical info? Thanks a lot and ALL THE BEST

[@JOHNWICK-hn3ng]

شكرا استاذ

[@PlayfulTechnology]

على الرحب و السعة!

[@lockdownescaperooms]

how would you add in more sensors (so all sensors had to be activated to release maglock?)

[@soundpreacher]

You can either wire them in series (so no current flows unless all are closed), or hook them up to multiple pins of an Arduino, and program it to need all activated.

[@juansalazar9476]

Can you create a code that once it reads 4 specific colors, maglock releases. If you make it with sounds even better. Please

[@supercables251]

Google "arduino color sensor" Or you can have make it cheaper using a neopixel (not a strip) and photoresistor