Uploaded January 2018 | Updated September 2026, 2 weeks ago
In this video I'll show you how to create two similar, although in some ways opposite, escape room-style puzzles involving a Light Dependent Resistor (LDR).
- In the "Cover Up" puzzle, players must place their hands (or any other object) over the LDR, raising its resistance to trigger a relay.
- In the "Shine On" puzzle, which uses identical hardware but a minor code change, players must instead shine a torch or other light source onto the LDR, lowering its resistance to trigger a relay.
The relay can then be used to power a load - release a maglock, play a sound, or activate any other sort of electronic device.
The code listing, documentation, and wiring diagram can be accessed by Patreons at patreon.com/posts/16239233
In this video I'll show you how to create two similar, although in some ways opposite, escape room-style puzzles involving a Light Dependent Resistor (LDR).
- In the "Cover Up" puzzle, players must place their hands (or any other object) over the LDR, raising its resistance to trigger a relay.
- In the "Shine On" puzzle, which uses identical hardware but a minor code change, players must instead shine a torch or other light source onto the LDR, lowering its resistance to trigger a relay.
The relay can then be used to power a load - release a maglock, play a sound, or activate any other sort of electronic device.
The code listing, documentation, and wiring diagram can be accessed by Patreons at patreon.com/posts/16239233
