# Light triggering a small circuit **URL:** \ **Category:** Factual Questions\ **Created:** [March 27, 2020, 1:55pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421 "2020-03-27T13:55:26Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [March 27, 2020, 1:55pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/1 "2020-03-27T13:55:26Z")
So my toddler has a woodblock puzzle. When a piece is put in place, the small magnet on the back of the piece triggers a circuit, which plays a sound (ambulance, jet plane, motorcycle, etc.). When I turn off the light in the family room at night, if the puzzle is sitting out, the circuit will trigger. What would be causing that to happen? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [March 27, 2020, 2:30pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/2 "2020-03-27T14:30:47Z")
Try throwing a heavy, dark blanket over it. If it still happens, it’s something to do with light, if it doesn’t, then it’s likely EMF from the light. I’ll bet the light is LED or CFL. You could also try bringing it to anther room with a different type of bulb, preferably incandescent, and see if you can repeat it. Also, just to confirm, this toy runs on batteries, right? It’s not plugged in. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 27, 2020, 3:10pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/3 "2020-03-27T15:10:13Z")
Are you sure it’s a magnet triggering it in the ordinary course of operations? Maybe the spot for each piece has a light sensor behind it, and it’s actually reacting to the piece covering the light. ---
**Author:** ![breezman](https://avatars.discourse-cdn.com/v4/letter/b/4491bb/32.png) [@breezman](https://boards.straightdope.com/u/breezman)\ **Post date:** [March 28, 2020, 12:00am UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/4 "2020-03-28T00:00:44Z")
Do you have any security cameras in the room with nightvision? If so, maybe the IR is somehow triggering it. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [March 30, 2020, 2:06pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/5 "2020-03-30T14:06:16Z")
> [@breezman](#): > > Do you have any security cameras in the room with nightvision? If so, maybe the IR is somehow triggering it. I don’t - it actually happens in a number of different rooms. > [@Chronos](#): > > Are you sure it’s a magnet triggering it in the ordinary course of operations? Maybe the spot for each piece has a light sensor behind it, and it’s actually reacting to the piece covering the light. It could be a small piece of metal maybe? There’s a puzzle piece where the metal/magnet fell out, and that particular one doesn’t work. > [@Joey\_P](#): > > Also, just to confirm, this toy runs on batteries, right? It’s not plugged in. Yup - button batteries. ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [March 30, 2020, 2:40pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/6 "2020-03-30T14:40:28Z")
I listened to a podcast interview with the founders of Melissa & Doug, makers of children’s puzzles, and the topic of “haunted puzzle” complaints came up. Even they seemed fuzzy on the science of the issue, but said it was just certain puzzles in a certain environment that caused the sound to activate when the lights were turned off. Fluorescent lights do weird stuff to radio frequencies. ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [March 30, 2020, 6:15pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/7 "2020-03-30T18:15:55Z")
Elmer - that’s the exact maker of this puzzle. Glad to hear other people are just as crazy as I am! ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [March 30, 2020, 6:55pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/8 "2020-03-30T18:55:30Z")
> [@Elmer\_J.Fudd](#): > > I listened to a podcast interview with the founders of Melissa & Doug, makers of children’s puzzles, and the topic of “haunted puzzle” complaints came up. Even they seemed fuzzy on the science of the issue, but said it was just certain puzzles in a certain environment that caused the sound to activate when the lights were turned off. Fluorescent lights do weird stuff to radio frequencies. Now that I think about it, I remember my (ex) FIL mentioning that if one of the baby toys was in just the right spot in the house, the furnace kicking on would trigger the toy to do whatever it did. ---
**Author:** ![sishoch](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@sishoch](https://boards.straightdope.com/u/sishoch)\ **Post date:** [March 30, 2020, 7:02pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/9 "2020-03-30T19:02:15Z")
My kids had a cookie monster doll that would say “cookie” when it was picked up. One day, I am alone in the house silently reading a book. I hear “cookie” from the toy box on the other side of the room. Very creepy. ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [March 30, 2020, 7:11pm UTC](https://boards.straightdope.com/t/light-triggering-a-small-circuit/850421/10 "2020-03-30T19:11:29Z")
When I lived with my parents we got a talking Shrek from McDonalds, but it was low on battery and instead of saying whatever it was suppossed to say it said, in a slow, creepy, slurred voice something that sounded like “Veroonicaaa”. It was very funny (for me) because “Veronica” is my sister’s name, she got seriously creeped out.