Laser Buttplug - How I Won Kink Halloween Contest

Description

Two years ago, I decided that a "sexy costume" simply wasn't going to cut it for the big kink/fetish/BDSM Halloween party costume contest. I wanted legendary. The result? A 3D-printed buttplug with integrated lasers and a fog effect, which won the contest so hard that the host declared me the first-place winner the moment I stepped on stage. The rest of the competition never stood a chance. Mission very much accomplished.

Details

The Build

The plug is 3D printed in PLA, carefully sanded, and coated with multiple layers of UV resin (a technique I've perfected after making many other "adult toys" - buttplugs included).

The extended base sits between the cheeks and houses two modified laser modules from AliExpress: A surprisingly powerful green laser and a red laser upgraded with a stronger diode salvaged from a DVD-RW drive.

Both beams are split into dozens of rays and reflected downward at 45° via small mirrors, creating a bright laser "tail" on the floor behind me - like some kind of cybernetic demon peacock.
For the fog effect, I built a custom vaporizer (0.5 Ω coil, 4 ml glass tank, small fan) running a 50/50 mix of propylene glycol and vegetable glycerin.

The whole system is controlled by an STM32F051K6 that handles multiple laser blinking patterns, smart heater-power ramping, and MOSFET-based PWM - like a proper embedded gentleman.
Power comes from two fat 26650 5 Ah Li-ion cells in parallel, carried in a small pouch on the belt together with the electronics and the fog system.

Connection to the plug is via a USB-C cable (although no actual USB protocol was used here, just the cable and connectors) and silicone tubing for the fog.

Remote control is done wirelessly with a foot switch hidden in my shoe. The confused and delighted reactions when people realized I was controlling everything hands-free were pure gold.

The Aftermath

The device was so well received that I took it out to a few more parties afterward. Nowadays when I show up at local kink/fetish events, people literally yell "Laser Butt Guy!" and similar shouts. I have never been prouder.

Safety & Sanity (yes, I still have both eyes)

Despite the absurd concept, safety was taken seriously. I've built 405 nm laser cutters/engravers, full RGB party scanners, and other laser projects before, so I'm not completely insane.

The plug itself contains only the laser diodes and optics - everything else (power, electronics, vaporizer) lives safely in the belt pouch. I'm not crazy enough to put Li-ion cells... elsewhere.

The beams are heavily diffused and intentionally poorly collimated (~10 mm spot at 3 m). In normal use they point at the floor. Brief sweeps across a crowd that was already dancing under strobes and club lasers? Acceptably irresponsible.

Note

I'm well aware this project is... unconventional. Because of that, I'm starting with this overview.

If the initial reaction here isn't too violently negative, I'll follow up in a few days with full technical details, a CAD cross-section, some photos, and maybe even a short video.

And I'll try to keep it as SFW as possible ;)

Project Logs

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Follow-up #2: The Fog System and the Brain
mumaque • 4 days ago • 0 comments
People are still not rioting, so let's dive deeper into the technical side - this time covering the fog/vaporizer system and the microcontroller that runs the whole show.

The Vaporizer / Fog Generator

For the fog effect, I used a Destiny 24 mm RTA from AliExpress, equipped with a 0.5 Ω Clapton coil and a standard cotton wick.

The liquid was a classic 50/50 mix of propylene glycol and vegetable glycerin with a single drop of baked apple flavor - because... why not?

Instead of using it as a normal vape, I built a small 3D-printed, sealed chamber around the tank. A small blower fan forces air through the bottom airflow ring, pushing the vapor out through a flexible 6×1.5 mm tube leading to the buttplug. The tube connection was secured with two or three layers of heat-shrink tubing for a tight fit. The enclosure also features a small viewing window (sealed with craft foam) and an LED on the opposite side, so you can check the liquid level at a glance.

Heater power comes directly from the Li-ion pack through a 50 A MOSFET module, controlled by PWM from the STM32. The fan is also PWM-driven, slightly overvolted from 5 V nominal to ~7 V. It features a soft ramp-down on shutdown, which nicely clears the remaining vapor from the tube.

The Brain - Custom STM32 Board

All of this is orchestrated by my own compact (30×18 mm) STM32F051K6 board with 1.27 mm pin headers.

I've made a whole family of these boards in different sizes - including larger ones for bigger, high-pin-count STM32 chips. They're significantly nicer and more practical than the classic Blue Pill (STM32F103) boards from AliExpress. And best of all, they're all my own design. ;)

The STM32 takes care of:
- Generating various laser blinking patterns
- Driving the heater PWM with a simple temperature model (cold-start boost followed by stable power)
- Controlling the fan with a soft ramp-down after turning off the fog
- Handling wireless communication with the foot switch
There is no temperature sensor on the coil and no fancy electronic liquid monitoring. I briefly considered doing a software-based liquid consumption model (kind of like coulomb counting for batteries), but quickly realized it would take more time and effort than the rest of the project combined. Sometimes the simple solution, like a visual window, is the correct engineering decision.

Any epic troubleshooting stories?

Surprisingly... none at all. Really. The whole project worked pretty much as I imagined. I'd love to entertain you with stories of heroic late-night debugging sessions, but unfortunately everything behaved suspiciously well.

Next episode

In the next (and last) post, I'll cover the wireless foot-switch remote control, the full power system, how everything was packed into the belt pouch, and some final thoughts about the whole build.

Stay tuned.
Follow-up: Buttplug and Laser Details
mumaque • 07/08/2026 at 20:44 • 0 comments

Since the initial post didn't summon an angry mob with torches and pitchforks, it's time for the first round of technical details.

The Plug Itself

The buttplug was printed on my trusty old Ultimaker (the classic one) at a 0.1 mm layer height. After printing, it was thoroughly sanded and coated with multiple layers of UV-curing resin - my standard process for making wearable adult toys. The result is smooth, durable, and body-safe. The extended base (the part that sits between the cheeks) was designed to house the laser modules and mirrors while keeping the internal volume minimal.

Here's the Fusion 360 cross-section (cropped for the comfort of the more sensitive readers):

You can see the two laser modules, the two first-surface mirrors mounted at approximately 45° (effectively), and the fog output channel running through the middle.

The Lasers - Maximum Effect, Minimum Complexity

I wanted a strong visual effect without going full laser scanner (which is totally possible, but would have taken way too much time). So I used cheap USB "starlight projector" modules from AliExpress (the ones sold as car roof ambient lights). Despite the listing claiming they were LEDs, they turned out to be actual laser diodes with diffractive optics that split the beam into dozens of rays.

Here's the original AliExpress listing:

Key modification: I completely gutted the original driver electronics from both modules. They are now powered by separate constant-current drivers located safely in the belt pouch with the rest of the electronics and the power supply.

Red module: Only the housing and diffractive optics remained. I replaced the original diode with a stronger one salvaged from a DVD-RW drive.
Green module: Kept the housing, optics, and the original green laser diode - it turned out to be surprisingly powerful.

The beams are heavily diffused and intentionally poorly collimated (~10 mm spot at 3 m), which was actually ideal for both the visual effect and safety. Two small mirrors reflect everything downward onto the floor behind me - perfect for a dramatic effect with almost zero mechanical complexity.

Next up

In upcoming posts, I'll dive into the fog/vaporizer system, the STM32 control board, the foot-switch remote control, and how the whole thing was connected and powered.

Stay tuned if you’re not easily scared off by a bit of embedded + kink engineering ;)