TL;DR:

My biggest fantasy is having an "automated slime room", where certain words or phrases could banned, and someone would automatically be slimed for saying one of them. I know this kind of overkill and probably horribly impractical, but I'd like to think it's possible to build an automated slime room in 2018 . I'm curious if other people share this fantasy or would find something like this interesting?

Also, if something like this were possible, what would you be willing pay for it? Note that I'm just curious - I have no intention of trying to sell something like this, though I may make plans freely available if I can design and prototype one (prototyping one probably won't happen for a long time since I live in an apartment... on the bright side, I have plenty of time to think about how this could actually be built).

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The long version (and nerdy stuff about how it could possibly be built -- probably not interesting to most -- just looking for fellow nerds who like a weird challenge):



In my fantasy of fantasies, I want to have a wetroom in my house one day, complete with waterproof furniture, a disposal unit in a drain on the floor, a shower, toilet, and a garden hose faucet for easy cleanup. One of the features I would like is several gunge tanks seated over various places in the room. Then I got to thinking... would it be possible to have a sliming mechanism that tracks a person as they move around through the room and automatically detect when they say certain words or phrases (which could be configured or even triggered spontaneously by a password protected web application)?

It seems like having parallel tracks along the top of two parallel walls of the room near the ceiling, with two parallel bars that ride on those tracks and can move along one axis of the room, and a bucket that sits on top of those bars and can move along the parallel bars (See this for an idea of what I'm talking about https://www.youtube.com/watch?v=WLSNJDoRnN4 -- instead of being small and moving a laser engraver around, it would be room sized and move around a slime tank and sliming mechanism) -- is a possible thing to do. One or more depth-sensing cameras could feed depth and visual information to software that would drive the servos and motors that keep the slime spiggot positioned over the highest point on the slimee's body. Further, voice or visual recognition could be used to both identify the slimee and identify when the slimee says the wrong thing.

Some challenges:
- The gunge tank would provide considerable weight on the metal bars. The metal bars that hold the gunge tank would need to be quite heavy, and the combination of weight and torque (due to flexing bars) along the side rails would be difficult to deal with. One way to solve this would be to suspend additional parallel tracks in the center of the room. This would complicate the driving mechanism that moves the bucket along the rails, but would be a considerably safer design due to the redundancy and the reduction of torque along the side rails. For a 10ft x 10ft (3m x 3m) room, at least one additional track would probably be needed.

- The room would need to be rectangular. Edges of the room may need to be blocked off (or the driving rails inset into the wall) since it's unlikely that the mechanism could slime someone who is standing directly against the wall. Chances are the room would need to be built custom (such as in a basement) to support the load imposed by the robotic bucket moving mechanism.

- The safety implications of having something so heavy above someone would necessitate the need for emergency stops if a side bar fails or if the gunge bucket detaches for some reason. Otherwise, a heavy gunge bucket and metal bars could fall on the slimee, and that's no good.

- Refilling the tank could be difficult (so the bucket would probably need to be lowerable), and slime would likely need to be stored for a while without spoiling (seems easily solvable with the right types of slime and topical preservatives; for example, a chunky slime such as natrosol and oatmeal, could be preserved for a long time assuming it stayed in a closed hydrophobic container and could not dry out).

- There would need to be a pressure release valve, which would also act as a fail-safe if the slime in the tank starts to go bad and begins off-gassing from microbial contamination. For example, if the topical perservatives failed for a given batch of slime. Further, there might even need to be a sensor mechanism to detect mold or other spontaneous defects in the slime. Alternatively, a cheaper version might include a camera that's mounted so that a visual check of the slime/gunge can occur from time to time to identify defects, such as mold or separation.

- The valve that regulates sliming would need to be tight enough that the slime doesn't drip out. Further, the top of the bucket would need to have a vent that opens automatically to let air in when slime is released.

- The bucket would need to be removable for cleaning. All valves would need to be cleanable.

- Parts would need to be replaceable.

- Electricity to each component would need to be low enough that accidental electrocution would be non-harmful.

That said, I think this might actually be doable though it would take a considerable amount of time to design and build. That said, some questions...

While I could probably do most (if not all) of this project on my own, I'm sure there are people who are better at some of these things than I am. That said, is anyone interested in designing this thing with me? (feel free to PM me if so)


Imagine the following, but as a room sized slime dispenser instead of a laser engraver:

Would people be able to move around in this room? If so, I would recommend perpendicular bars, one for the X axis, one for the Y axis. If not, then nevermind.

Also, I think you need to think...outside the bucket. From what you've described, it sounds like the slime is poured out the bucket, by tipping it over. This can lead to misses. I recommend drilling a hole in the bottom and using a plug. An automated lever can flip up, which is connected to the plug, allowing the slime to fall directly down. Think of a toilet tank. The down side to this is it would never fully empty.

Next, as far as weight goes, you can calculate this by adding your dry ingredients' weight to your liquid ingredients. Water, at room temperature, weighs 8 lbs per gallon. Depending on the size of your bucket, that could be anywhere from 9 lbs of weight to 45 (estimates, assuming a 1 gallon bucket to a 5 gallon bucket). I have a setup where a 20 lb bucket is suspended from a pulley in the ceiling, and the rope goes through a guide on the back wall. The guide has come out several times (about once every 6-9 months), but the ceiling hasn't ever. The ceiling pulley is in a stud. I keep trying to find the stud on the wall, but my stud finders always give me crazy results.

As far as spoilage, I recommend waiting until you're ready to use it to prepare it, depending on what type of slime you're making. You also need to consider temperature. Are you looking for cold slime, warm slime, etc?

One final thing to consider is sway. With the bucket being free-hanging, any side motions will cause the bucket to sway, leading to a slime that is all over the place. I have been able to minimize sway by running the pull cord up and through the connecting link. When I first started the cord ran over the side. You can tell in my older videos that the slime does move around a lot. Also, remember, the further a point (X) is from the pivot (P) while the bucket is swaying, the greater the resulting sway will be.

As far as the technical side of things, that's beyond my paygrade.

Would it be easier to keep the gunge tank stationary and use a pump to spray the gunge across the room? You would then need the "gun turret" to automatically rotate, and possibly tilt up and down, tracking the person as they move. The main advantage is that it would still work for someone in the middle of the room rather than requiring people to stand against a wall. Also, you wouldn't need to worry about weight limits because you'd just need one solid frame to support the tank.

@Saffron3.14: Once the basic word recognition functionality is in, it would be super easy to add games like you suggest . They might have to be multiple choice unless they are one word answers (and you can have multiple answers per question to handle synonyms). I love that idea!

@piboivia: In the design that I posted, the bucket would have a spiggot with an electrically controlled valve so the bucket would be fixed upright on top of the platform that slides along the bar(s). The idea of using two metal bars was my first idea, but I simplified the napkin sketch a bit when I saw the laser engraver in the video that I linked to this post. The weight of the bucket would be a huge concern, especially when you consider that the center of mass won't be static, so a two-moving-perpendicular-bars design would likely be a lot more stable. My thinking was that the bucket would hold around 10L-20L (2.6-5.2G), but even that is a lot of weight to be moving around (especially when you consider acceleration) and so I'm concerned about that.

@steve: that is a very interesting design, using belts. My thought was that the "bucket" could be refilled automatically by storing gunge in a much larger container that has a fixed location. To handle refilling in the design I posted, I expected that the bucket would simply move to the right location, gunge would be pumped up into the bucket, and off it would go, ready for its next target. Also, a moving chair would be cool, though I like the idea of someone being able to go about their life normally and all of the sudden get slimed for saying the wrong thing.

@flank: shooting gunge would be a cool addition! I'd be worried about the hydraulic needle effect and possible injuries, but it still might be a hilarious thing to have if those safety concerns could be addressed. On a related note, I wonder if it would be possible to make an automated pie thrower? Also, my concern about walls is that the mechanism wouldn't be able to slime someone who is standing near a wall (rather than requiring them to stand near the wall to be slimed). The sliming mechanism would be able to move across an entire room, but there would be a dead zone near the walls where it would be unable to slime someone unless measures were taken to remove it.

Another person PMed me and brought up the idea of putting the automatic sliming mechanism on top of a large gunge tank that multiple people could sit in - maybe a 2m x 2m area with transparent walls. This way, the gunge dispenser that sits on top of this smaller tank would no longer have to hold the gunge on top of it - it could instead move the tip of a hose around. The hose would be connected to one or more larger containers of gunge stored outside of the tank, and slime would be pumped up to the hose. To me, this seems like the most practical design as it avoids the weight issues. Lower weight will mean a better response time if the slimee moves, ensuring that they can't move quickly to escape the slime. That said, it would be hard to have a natural interaction that results in an unexpected sliming (by willing participants) this way, but there is definitely still practical value to it (games, etc). Alternatively, if the room being rigged is small enough, this design could also be used. At some point, the length of the hose would become prohibitive I would think.

If anyone's interested, I'll be happy to create a Slack or Discord channel somewhere?

Also, I love all of these suggestions!

I think another challenge with a small room is acoustics. If you are in a small room with solid walls there may be an issue with echoing and this would perhaps be a challenge in a speech recognition device determining specific phrases, location of the individual, & correct identification of target individuals.

This could perhaps be corrected through the use of lapel microphones? Also, upon entering, the device would most likely need to calibrate the room & participant location. Maintaining accuracy of moving targets is an incredible challenge.

@DarthPtolemy1: Good call on speech recognition and acoustics. Some foam padding on the ceiling might be able keep the sound waves from bouncing around too much? For locating and tracking targets, I'd recommend LiDAR over acoustic triangulation.

@steve2381: This is basically what I was thinking -- using a one or more small computers like RPi's. For example, we'd probably want a computer that handles LiDAR and target tracking to find a target's approximate location. From there, a computer on the sliming mechanism could fine tune it's movement to get a precise location. Because LiDAR is image-based triangulation, a camera's FOV and resolution both impact precision as distance from the camera(s) increases. Does your current setup handle detect distance to the camera?

With something that small, you could probably just use a battery instead of wall electricity. The chance of electrocution becomes 0. While I know fuck-all about electricity and programming, I don't see why a watch battery couldn't be used.

For controlling the cameras and computers, a small number of batteries would be fine. For motorized mechanisms, more electricity would be needed as a battery likely wouldn't be enough. Also, batteries come with chemical risks if they get wet (though with the number of batteries needed for a few small components, that would be a non-issue).

I created a discord server for anyone interested

https://discord.gg/Kpv9S3Q