Halloween Mirror Offers A Mighty Fright

Jump scares are controversial in the horror world, whether you’re talking about movies or video games. You can bring that same irritating thrill into real life, too, with this Halloween mirror from [jasonwinfieldnz].

During the day, or simply when it’s bright inside, the mirror appears normal, like any other. However, behind the special two-way mirrored glass surface is a spooky 3D print, such as a skull or an annoying yellow cartoon character. When the lighting level gets low, everything changes. A light-dependent resistor hooked up to a Digispark detects the change, and then fires up some 5V LEDs to light the scary image, revealing it behind the mirror. Even better, it plays a loud screaming sound with the help of a DFplayer MP3 module.

We’d love to see the concept taken even further, too. It would be quite something if, when a passer-by approached, the room lights suddenly cut out and the mirror activated in its full glory.

We’ve seen some great Halloween builds over the years. If you’re eager to get one out this season, you might wanna get hacking now! Video after the break.


22 thoughts on “Halloween Mirror Offers A Mighty Fright

    1. Why do you allow him to still live in your head? Self-made problem, IMHO. I completely forgot him.

      On another note:
      Just like how everyone forgot Assange and nobody wants to rescue him.

    1. Never mind.

      For the younger readers born in the 90s/00s: You don’t need explicitly a microcontroller to do that. In fact, it doesn’t add anything meaningful. A capacitor or a 555 timer can be used for delay, if needed.

      A light barrier can be build fully analogue with an light dependant resistor (LDR), a photo diode or a very vintage photo cell (selenium cell). Even solar cells can be used. Photo transistors, too. Some ordinary vintage transistors in a glass housing can be used, too, if the paint is scratched off.

      Additionally, a few resistors, a transistor and a mechanical relay is used traditionally to build a light barrier.

      If you really really want to go all vintage, a battery tube can be used in place of a transistor. But even back in the 1960s, people used Germanium transistors like the AF151/AF121.

      1. It’s cool that YOU know how to do things the archaic way, but new tools are continually invented that can do the same job cheaper and/or easier. Should it have been a carved face instead of 3d printed?

        Horses can still pull carts, but cars are easier.
        Powered lawnmowers are better than push mowers or a scythe.
        Telegraph > POTS > pager > flip phone > smart phone…..

        Not sure why you’re crapping on someone for doing something the way THEY learned vs the way YOU learned. Why should they track down a “very vintage” selenium cell and make something from scratch instead of spending $0.50 on a modern part. This site isn’t supposed to be a place to tear someone down for making something differently than you would have; it’s here to celebrate people finding their own way to do something.

        1. “It’s cool that YOU know how to do things the archaic way, but new tools are continually invented that can do the same job cheaper and/or easier. Should it have been a carved face instead of 3d printed?”

          “ok boomer”

          Just kidding.
          It’s a cultural/generation thing, I guess.

          My intention is to preserve/share existing knowledge, not to raise myself up.
          See, I’m not a boomer, Gen X or something. I’m too young for 30+ parties, even.
          I rather grew up with 1990s technology, that’s why.

          Back then, our electronic construction sets simply used such schematics still.
          To teach basic skills about electronics.

          That’s what today’s generation misses out, because it’s too impatient sometimes.
          People at HaD and other places jump start directly into digital electronics without even teaching basic skills.

          But without a good foundation, you can’t construct something that lasts. It will make technology control you, not the other way round.

          Knowing how a transistor, diode, lamp, capacitor, resistor works is something which the youth can benefit from.
          It’s not that they have to learn everything about it, but an abstract understanding of the concept is really helpful.

          It will teach basics that are really handy when working with MCUs, too.
          For example, the fact that too long wires can work as antennas or have capacity. Or how important a good, clean power source is (no ripple, RF etc). What shielding and grounding are good for. Why fuses should be installed sometimes.

          All this will help troubleshooting if the MCU will crashnor reset for no apparent reasons.
          Especially if said very long wire is attached to a MCU’s pin directly.

          Believe it or not, children books from the 1970s/1980s explained this.

          Here are examples about computing:



          The Usborne Publishing books also covered other topics, not just computers. In fact, I own some of these books.

          Best wishes,

          1. Back in 1977, the Vo-Tech I attended first taught us vacuum tube theory (we complained about having our time wasted on archaic technology), before teaching us about FETs (which operate on similar principles), before moving us to BJTs, and then ICs (analog and digital) .

        2. Indeed as technology progresses there can be better tools for the job, but that doesn’t mean old tools become obsolete.

          Take driving a car vs walking, sure most of the time car beats walking in terms of speed and efficiency. But there are times when a car isn’t really appropriate – need to go to the shop on the other side of a river where the nearest road bridge is 2 miles away, yet there’s a footbridge 30m away? Just because you can use a car, doesn’t make it better than walking here.

          1. Interesting red herring, but I bite. Explain me why a leaky Germanium diode is better than a modern schottky? bat46 bat85 1N5711
            Edge cases like crystal detectors were replaced by these too.

        3. It just reminds me of the Chixulub impact: one last time the dinosaurs reared up, one last cry of “I am the Apex”. But evolution had created smaller and more efficient life forms. More favorable in their energy efficiency.

          The dinosaurs still exist today, refusing to learn the new ways in their obsession with nostalgia. I am glad we can safely ignore technological trash such as the carbon microphone. To the ash heap of techno-history!

          1. The only reason that dinosaurs still exist is that for millions of years they had only one goal: to annoy the hell out of those pesky mammals that took over from them, by shitting all over their property. :D

          2. Hm. How’s that old saying going again? “The condemned live longer”?
            – Or was it: “There’s Life in the Old Dog Yet”? 🙂

            Either way, by the end of this century, when all current technology is gone,
            somewhere, someone will be still be running a C64 or MS-DOS PC. 😁

            And dynamic mikes are awesome, btw.
            Much better than both carbon and condenser microphones!

            Just like speakers, they have good quality.
            That’s why back in the day, people used the speakers (!) of telephone handsets as high quality microphones.

            Sure, a little pre-amp was needed. A one-transistor amp based on a BC548 or 2N2222 would do.

            By the way, Nuvistors (a tube/transistor intermediate step) were used in HQ microphones once. And in high-end scopes.
            They’re still great technically, but difficult to manufacturer.

      2. Don’t they sell night lights that have a sensor that only turns on when it’s dark? I pretty sure we had one when I was a kid, and it does exactly what is needed off the shelf.

          1. True. Back in the 90s, we used the circuits inside of these recordable greeting cards for such experiments (instead of a cassette player).

            You know, greetings cards.. Those physical cards made from paper. They were folded in the middle.

            If someone opened the electric greetings card, a contact switch was operated on the little PCB that was hidden inside with a strip of tape.

            The PCB had a coin cell, a little black blob (the IC) and also had a little piezo speaker. Sometimes a microphone, too, if the speaker wasn’t also used for recording.

  1. Is it just me, or would a more subtle implementation be scarier in some ways? What if the lights glow so the skull is just barely discernable, encouraging one to peer more closely, to wonder if you really saw what you think you saw? Or the lights could flicker like a loose connection… Or pulse like a heartbeat. Could this be made with some sort of gaze tracking so the image only appears when the viewer is looking mostly away? So much spooky potential…

    1. That’s an interesting way of thinking!

      I suppose, it’s a matter of Zeitgeist here.
      Back in the 1970s/80s, there were films that didn’t have much action, but were incredible thrilling and haunting!

      Like ‘The Fog’, ‘Alien’, ‘Poltergeist’, ‘Westworld’, ‘Close Encounters of the Third Kind’. Films like that.

      Look for “flasher” code samples or schematics.
      These will fade an LED or lamp smoothly back and forth. 🙂

      The heartbeat thing can be made by a blinking LED.
      If you wire it to a transistor base as a driver, it acts as a cheap timer IC.

      Alternatively, a MCU code sample can be used here as well.

      Back in time, a blinken light (blinking lamps) was used instead. It was wired in series to the power source of a electro-mechanical relay. Of course, car blinkers could be used, too.

      Btw, if you wire a classic relays in such a way that it will disconnect its own power supply, it will buzz like crazy. An attached lamp will flicker accordingly. That being said, a capacitor should be added to slow things down a bit. Otherwise, the relaysl contacts will wear out quickly.

      The person/viewer detection could be implemented by using infrared LEDs/infrared diodes.
      Once the infrared light barrier will have an object (person) stand in front of it, the infrared beam will be reflected back.
      There are combined infrared transceivers for this on sale, I believe.

      Of course, an MCU can be involved in the process, too.

      A infrared thermal sensor or a radar sensor, as used in those outdoor lamps, could be used too, I guess.

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