Need help / Question concerning pressure in inflatable toys

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OrgasmAlley
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Re: Need help / Question concerning pressure in inflatable t

Post by OrgasmAlley »

Interesting perspective on what it means to be a forum moderator. I always assumed that someone -- moderator or not -- posting to the content of a thread is doing so as a forum participant. Moderator has, to me, always meant specifically a role controlling the behavior of a forum, not its content, excepting the enforcement of the rules about allowed content. If a moderator is acting in that role, I would expect them to identify it explicitly.

I do think the several comparisons of this scenario to high pressure air are over the top, though. Tire inflation (perhaps 80 PSI) and the sort of thing one will find searching "pneumatic injection injury" are not well-aligned with the output from a 3 volt 1-1/4" long plastic air pump from a BP monitor, IMO. That said, my rather gentle statement was certainly not intended to question anyone's right to post their perspectives of any sort, but to express my own beliefs about people's responsibility for themselves and their use of information they collect.

In expressing my opinion it was certainly not my intent to ruffle anyone's feathers, which I have clearly done.
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Re: Need help / Question concerning pressure in inflatable t

Post by Keyless »

OrgasmAlley wrote: Tire inflation (perhaps 80 PSI) and the sort of thing one will find searching "pneumatic injection injury" are not well-aligned with the output from a 3 volt 1-1/4" long plastic air pump from a BP monitor, IMO.
I'm not so sure that a pump from a blood pressure meter would be safe. After all, it can generate enough pressure to cut off the blood supply of someone with really high blood pressure - and a bit to spare. Squeezing inwards might be a bit painful. Inside pushing outwards must surely be questionable.
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Re: Need help / Question concerning pressure in inflatable t

Post by BornThisWay »

OrgasmAlley wrote:In expressing my opinion it was certainly not my intent to ruffle anyone's feathers, which I have clearly done.
You didn't, I get slammed all the time about safety related warnings. What frustrates me is self-bondage is inherently a dangerous undertaking. Sometimes when dealing with stuff like electricity, a warning is appropriate. Othertimes, especially if the person is not a moderator, I just want to slap the buzz kill for polluting my post by trying to point out the painfully obvious fact that bondage is dangerous.
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Re: Need help / Question concerning pressure in inflatable t

Post by Gregovic »

OrgasmAlley wrote:Interesting perspective on what it means to be a forum moderator. I always assumed that someone -- moderator or not -- posting to the content of a thread is doing so as a forum participant. Moderator has, to me, always meant specifically a role controlling the behavior of a forum, not its content, excepting the enforcement of the rules about allowed content. If a moderator is acting in that role, I would expect them to identify it explicitly.

I do think the several comparisons of this scenario to high pressure air are over the top, though. Tire inflation (perhaps 80 PSI) and the sort of thing one will find searching "pneumatic injection injury" are not well-aligned with the output from a 3 volt 1-1/4" long plastic air pump from a BP monitor, IMO. That said, my rather gentle statement was certainly not intended to question anyone's right to post their perspectives of any sort, but to express my own beliefs about people's responsibility for themselves and their use of information they collect.

In expressing my opinion it was certainly not my intent to ruffle anyone's feathers, which I have clearly done.
They are not immediately comparable, but you'd be surprised how much pressure even a small pump can put out. I really don't intend to be a buzzkill with this sort of stuff, I'm just a massive pessimist and I easily assume people shouldn't be messing with this sort of stuff if they have to ask these questions. It's REALLY easy to do damage to a part of the body as soft, squishy and full of large blood vessels as the colon and rectum. I get the idea, and I have thought about doing something like that too. The idea put forward by Bornthisway about limiting the amount of volume available for pumping is the best idea so far for limiting the danger of overinflation. The problem is that any leak over time might increase the volume available for pumping. Personally I find the risk to be too high. Someone else might think of this differently.
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Re: Need help / Question concerning pressure in inflatable t

Post by lj »

OrgasmAlley wrote:Interesting perspective on what it means to be a forum moderator. I always assumed that someone -- moderator or not -- posting to the content of a thread is doing so as a forum participant. Moderator has, to me, always meant specifically a role controlling the behavior of a forum, not its content, excepting the enforcement of the rules about allowed content. If a moderator is acting in that role, I would expect them to identify it explicitly.
+

I am not trying to control the content of this forum, but expressing a personal opinion on the safety of the topic. I mentioned my Moderator status simply because I have seen scenarios posted that were suicidally dangerous and have prevented them reaching the forum so that those with lesser experience do not risk their lives attempting to put them into practice.

As with electricity, pneumatics needs to be well understood. The human body is designed to work with atmospheric pressure, relative deviations of pressure are outside of the design parameters. A couple of psig difference with a couple of litres of air will blow the rectum apart. A few cc at the same pressure will do nothing. Be sure you know the difference. That's all.
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Re: Need help / Question concerning pressure in inflatable t

Post by OrgasmAlley »

It seems useful, at least to me, to discuss the methods and modes of failure... and possible remediation.

Arduino + power supply. Could fail. Power could go out, power supply could fail, a component on the Arduino board could fail. I've used Arduino boards for around a decade commercially and haven't see a failure in a proper install, however. It is possible to blow a single pin by sinking too much current (20 mA limit), though... and sometimes a neighboring pin goes with it. In all of these cases, you're going to remove power from whatever you are operating. For this reason, you should power your pump in a way that removing power at the logic level does not result in continued operation. Pin HIGH = run, in other words.

Logic level to high(er) current interface. You'll be using something like a small physical relay or a MOSFET to allow the logic level pin output to control the higher current pump. This interface could fail. You'd use a non-latching normally-open device, such that removing power (for any reason) turns the connected device off. A typical relay will have a mechanical durability rating of perhaps 10M cycles, and an electrical durability of 100K to 200K cycles. Electrical failure means a coil problem or contacts that won't contact... this failure mode does not power the device. There is a theoretical mechanical mode of failure in which power continues to be delivered despite the removal of power to a relay, although I've not seen it except at high voltages. If desired, one could mitigate this by using two relays in series controlled by two different pins, but it's extremely unlikely given the expected mechanical durability and low voltage and current. If employing a MOSFET, it will have an expected lifecycle of many millions of actuations within specs and fail into a disconnected state.

Pump. This could certainly fail. If it does it stops running.

Solenoid release. This could fail, and any mode of failure almost certainly means it will not release pressure. There isn't any rating information, but we can make some assumptions. 1. It's pretty reliable, because it's inside a medical device. 2. It probably does not have a high duty cycle, because its application involves releasing pressure once in a great while. One might be able to physically reverse it, and run it such that power is required to keep air in the device... but I'd suggest it's not likely to hold up to that. If one is concerned about not releasing, redundancy would be the solution,

Basically, I'm not sure what the exact concern is about a runaway pump. Bad code could do it, as could poor design coupled with a failure of some component. A physical relay can theoretically fuse closed, although you're more likely to hole a 500 yard par 5 off the tee if you're well inside a relay's ratings. Using basic decent design, any failure but the most rare turns the pump off. Those who have this concern... in what way does a controller for this pump or the pump itself fail and keep running? I don't see it.

I conclude people with safety concerns are assuming the OP or other user of the OP's device will be inescapably bound, and thus unable to turn the pump off if it (somehow, although I don't think there is a way) became stuck on. That wasn't in the initial scenario. However, it seems worth noting that this BP monitor pump A) does not produce a great deal of pressure and B) does not move a great volume of air. I would describe it as slow, and incapable of producing sudden and/or unexpected inflation. We are not connecting to an air tank at 100PSI here, although I have at least two customers who do just that.

Concerns with air entering the colon also seem unfounded to me, but I use high quality inflatable toys and test them regularly by inflating well beyond the possible size in situ. I'm not sure how people think air gets from inside the toy to loose inside the person. The toy would have to fail, but that means expansion beyond what it can take... and THAT does not happen (with a decent toy) when it's inside the body cavity. Increasing pressure would first cause discomfort, then pain, then extreme pain... it's not even clear that quite high pressure inside a quality toy would be able to expand it sufficiently to burst, because I don't think the body itself can expand to that degree. All toy dependent... but I've had my Mr. S butt plug up to the size of a volleyball, no problem. This little pump certainly isn't going to make that happen inside a human body. Zero chance.

In case it's not obvious, I've actually built what the OP is asking about, and used it repeatedly for maybe a year. Before that, I was using a similar device that employed water instead of air. I build sex toys for a living, and have for 17 years. I've built them a lot longer than that, because one of my big kinks is machines/automation type things.
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Re: Need help / Question concerning pressure in inflatable t

Post by OrgasmAlley »

lj wrote:I am not trying to control the content of this forum, but expressing a personal opinion on the safety of the topic.
OK. Sorry that I found this unclear.
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Re: Need help / Question concerning pressure in inflatable t

Post by Riddle »

So, we now have plenty of responses and are no further toward answering the OP questions. There is only one way to find out what is needed to operate the inflatable safely:
Riddle wrote:May I suggest an experiment to find the minimum and maximum pressures? Connect a pressure gauge inline with your inflatable plug and watch the pressure as you inflate it. Probably start with a 30 psi gauge and see if you need a different gauge...
We do know that the rectum and colon are delicate and must not be blown up. We also agree that a pump capable of swiftly inflating a tire is way too dangerous for this application. This application requires low pressure and low volume. We have one member who successfully used a blood pressure monitor pump without blowing out his inflatable plug.

This brings us back to the OP questions:
Blacky wrote:My problem now is, that I have absolutely no idea how much pressure will be needed to inflate the plug.
The second part of the problem is that I'd like to be sure that the pump will not create too much pressure, as I don't want to risk injury. :shock:

Can anybody here provide any reliable data concerning the minimum and maximum pressures that are going to be needed respectively should not be exceeded?

Thanks and kind regards,

Blacky
We need someone to measure the inflatable plug pressures using the original hand pump and share those numbers with the rest of us. This can be done by plumbing in a t-fitting into the inflatable air line and adding a pressure gauge at the t-fitting. I suggested a 30 psi gauge as a commonly available value. A 15 psi gauge may be more precise, but may be harder to find.

My guess is that the required max pressure is about equal to a 4 foot water column of pressure (1.732 psi). Enemas are usually given about 18-36 inches above the plug for 0.650 to 1.300 psi. Blood pressure is measured in mm's of mercury up to about 180 or so. Beyond 180 is a medical emergency; that 180 mm of hg equals 3.481 psi. Good evidence that a blood pressure pump could be safe in this application if controlled properly.

Of note, the hand bulb pump on inflatable plugs is basically a manual blood pressure pump on the old analog devices.

The trick will be finding a pressure transducer that works with Arduino for a reasonable cost. Take this for example:

https://www.amazon.com/Pressure-Transdu ... ducer&th=1

The max pressure on the lowest version is 0.5 MPa or 72 psi. We only want 0-4 psi... Another option is a MAP (manifold absolute pressure) sensor such as this:
https://www.summitracing.com/parts/avm- ... /overview/

Too bad the prices are outrageous...

So, who is going to gauge their butt plug, you know, for science!
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Re: Need help / Question concerning pressure in inflatable t

Post by lj »

@OrgasmAlley an excellent examination of risk, you clearly understand what you are doing.

On occasion, as alluded to earlier, some people post scenarios that clearly indicate they haven't considered any form of failure, nor how to cope with possible failures, and so anything that is posted, where the risks seem to have been ignored, will receive our attention. Similarly, a post by an experienced person may encourage a much less experienced person to try the same scenario but with inferior equipment and knowledge.

One of the main aims of this forum is to help people to enjoy their fun and continue to do so, rather than end up injured or dead. Any input of this nature is very welcome, from anyone.
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Re: Need help / Question concerning pressure in inflatable t

Post by Riddle »

Smartec makes a dip sensor for 0-5psig available in the US for $12.
http://www.smartec-sensors.com/cms/medi ... asheet.pdf

Their list of distributors is rather extensive, there should be a vendor in your country...
http://www.smartec-sensors.com/cms/page ... butors.php

That solves the low pressure reading requirement with an Arduino.


Another recommended part is the following:
https://www.amazon.com/Midwest-Control- ... lief+valve
This pressure relief valve will prevent dangerous pressures by venting off excess pressure beyond the set-point. Highly recommend for all pneumatic systems especially if delicate items are attached. Unfortunately, we still do not know our max psi.
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Re: Need help / Question concerning pressure in inflatable t

Post by Blacky »

It seems that actually nobody has, up to now, measured the pressure inside their toys.
I wouldn't ask any of you to sacrifice their toys, so I don't need to sacrifice mine, either.

What I'm about to do is as follows:

I will order a BP-monitor, most likely this one
http://www.pollin.de/shop/dt/NzUyNjMxOT ... D1210.html.

Once it has arrived I'll try to find out how to best make use of the pressure sensor. This will most likely result in it being added to the manually operated toy.
Once I manage to get that working properly I'll add the pump and the release valve to the setup.
Next will be a test rig (most likely a toilet paper roll) in which I'll let the system automatically inflate until a shut-off pressure is reached (preferrably before the roll bursts), , then deflate, reinflate...

Once that works I'll use it to find out about the pressure limits. I'll add two pushbuttons, one used to activate the pump, the other to activate the valve, effectively creating different levels of pressure (none, barely noticeable, ... , slightly uncomfortable, [maybe] slightly painful). It might well be that I'll leave the last one out, though, as I am well aware of the inherent dangers.

If, and only if this approach delivers reliable and reproducable values I'll turn the code upside down and let the system take control of the pump again.

I'll keep you informed about any progress. Thank you all for your help. :love:
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OrgasmAlley
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Re: Need help / Question concerning pressure in inflatable t

Post by OrgasmAlley »

Glad to see that we're moving forward... is seems like we can assume there is no mode of failure (assuming the system is properly sized, assembled, and coded) in which the "runaway pump" scenario is as likely as say a house fire.

Blacky, your sensor looks quite similar to what I dug up but about 10x the price ;) I have a little pack of these sitting around somewhere: https://www.banggood.com/3Pcs-DIP-Air-P ... 85846.html

40 kilopascal is 5.8 PSI, and like you I've concluded that's likely to get the job done. I believe you'll need to amplify the output from this chip for an accurate reading on the Arduino. Quite honestly, I got distracted by another project... there's a huge stack of such things in my life ;)
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Re: Need help / Question concerning pressure in inflatable t

Post by Hitmeup »

https://www.digikey.com/products/en?keywords=MPX4250AP

these are easy to read easy to power and are good from 2.9 psi to about 29
but they read lower
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Re: Need help / Question concerning pressure in inflatable t

Post by OrgasmAlley »

If it does in fact read lower, that's a nice one. Straight analog read, very cool!
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Re: Need help / Question concerning pressure in inflatable t

Post by frobble »

Hi,

I'm taking the opportunity to delurk here, as I have been playing with devices like these recently for, um, related purposes. Just wanted to point out that there are two very different "models", measuring absolute vs relative pressure. I first bought this one https://www.digikey.com/product-detail/ ... -ND/464052, not paying attention to this fact. Seemed to have a nice range, 15 - 115 kPa - but atmospheric pressure is approx 100 kPa, and it measures absolute pressure, meaning that what you would naively consider "no pressure at all" gives a reading of about 90% of max - not good. Got this one instead https://www.digikey.com/product-detail/ ... -ND/464055, with 0 - 10 kPa relative pressure. The one listed in Hitmeup's post is 20 - 200 kPa absolute, so will probably work fine, but you won't be using the lower 45% of the range in this application...
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