This video tutorial explains how to build your own "knife-throwing" escape room puzzle, inspired by impalement arts tricks performed in the circus or carnival.
The wooden board has a number of slotted holes, arranged to narrowly miss the outline of a lucky target. When players insert knives into the correct slots, they block a beam of infrared light which is detected by a sensor, a sound effect plays, and a relay is energised to release a maglock.
This example uses an ESP32 as a controller, but the code logic would also apply to any Arduino, ESP8266, or similar microprocessor instead.

To install the IR sensors onto the board and make sure they are aligned correctly either side of the slot, I'm using a 3D-printed mount as described in this video:    • Creating a 3D printed electronic sens...  
If you don't have a 3D printer, don't panic - you can screw the sensors in place, or attach them some other way instead.

Timings
00:00:00 - 00:01:23 Introduction and Demonstration
00:01:24 - 00:03:07 Hardware Overview and Assembly
00:03:08 - 00:08:11 Wiring the Components
00:08:12 - 00:18:28 ESP32 Arduino IDE Code Listing
00:18:29 - 00:19:33 Wrapup and Conclusion

For more information on this build, or to access the resources used in this and any of the other escape room projects featured on this channel, please see   / playfultech