Need help / Question concerning pressure in inflatable toys

Ideas and instructions how you can make your own bondage toys.
lezlietv
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Re: Need help / Question concerning pressure in inflatable t

Post by lezlietv »

As a health care professional, we insert tubes with inflatable cuffs into the body all the time. Those that have cuffs that come into contact with tissue for extended periods of time must not exert over 25 -30 cm H2O. 555 cm H2O is atmospheric pressure= 14.7 lbs psi. So basically one twentieth of and atmosphere. Anything higher will prevent blood flow in the capillaries and lead to sores and ulsers. An inflatable butt plug will have a certain internal pressure even if not inserted but please be careful especially if using for extended period of time
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Re: Need help / Question concerning pressure in inflatable t

Post by smelt »

Blacky, Did you ever get an actual pressure reading on a gauge? I have an old butterfly gag, and had actually thought about a T fitting, and a vacuum/ boost gauge just to see what psi it takes to be uncomfortable. I could throw it together just to get a baseline on what the gag's pressure is, but as most of us know, it's not going to be a lot. The only inflatable plug we ever had didn't last very long, and felt like it took less pressure than the gag. I will try to get some readings over the rest of the weekend, in between all the other experiments I need to do.

I was thinking along the air reservoir lines, we used to insert tire valves into the caps of 2 liter bottles, then charge them up with air til we got a big noise. You could probably make a reservoir from a "high pressure" soda bottle easily, that way if you had 2 adjustable solenoid valves (air ride valves from a car, maybe??) , air could be released as needed, and be released from the plug. You could inflate the bottle to only a safe working pressure, so the risk of over-inflation would pretty much go away. This would be a one-time use only, unless you had a larger pressure vessel. Hmm.. I have several air tanks out in the shed.... 60 gallons of air, at say 4 psi delivery, would allow an awful lot of cycles of something like this....
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Re: Need help / Question concerning pressure in inflatable t

Post by Blacky »

lezlietv wrote:As a health care professional, we insert tubes with inflatable cuffs into the body all the time. Those that have cuffs that come into contact with tissue for extended periods of time must not exert over 25 -30 cm H2O. 555 cm H2O is atmospheric pressure= 14.7 lbs psi. So basically one twentieth of and atmosphere. Anything higher will prevent blood flow in the capillaries and lead to sores and ulsers. An inflatable butt plug will have a certain internal pressure even if not inserted but please be careful especially if using for extended period of time
Thanks for the information. As I said before, I will be careful.

smelt wrote:Blacky, Did you ever get an actual pressure reading on a gauge?
Unfortunately I don't have the equipment. I'd also like to avoid having to buy it as I would most likely never need it again. :?
I was thinking along the air reservoir lines, we used to insert tire valves into the caps of 2 liter bottles, then charge them up with air til we got a big noise. You could probably make a reservoir from a "high pressure" soda bottle easily, that way if you had 2 adjustable solenoid valves (air ride valves from a car, maybe??) , air could be released as needed, and be released from the plug. You could inflate the bottle to only a safe working pressure, so the risk of over-inflation would pretty much go away. This would be a one-time use only, unless you had a larger pressure vessel. Hmm.. I have several air tanks out in the shed.... 60 gallons of air, at say 4 psi delivery, would allow an awful lot of cycles of something like this....
This is surely a nice idea, but the basic idea for the whole setup was too keep it as mobile as possible. Thanks anyway :D
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Re: Need help / Question concerning pressure in inflatable t

Post by smelt »

Sorry, I forgot to post my findings on here. So it seems that, until the latex of the gag stretches to near it's limit, the pressure doesn't amount to much. I got no real rise in pressure, til it was stretched very tight, and I was afraid it would burst. I was unable to get a very good reading, it seems turbos make more PSI than my butterfly gag. That being said, my gag is MUCH thicker than the glove-like sheath over our old inflatable plug. A better way to do this, might be a very accurate regulator, and increase slowly (out of the body), until you get the effect you are looking for.

As for portable, I have a couple SCBA tank setups, which starts out at 2216psi. I used to use it in junkyards, to run my impact gun. Regulated down to 150 psi, it lasts quite a while, running the impact. I would probably not trust a regulator to protect me from the effects of 2216 psi in my back door. But just another outside-the-box idea we came up with a long time ago. Its used for airbrushing now. The air is good enough for a firefighter to breathe, I figure that's pure enough for paint on a car.


One last idea... I don't have one, but what about an aquarium pump? I know they aren't capable of much pressure, but it may be enough. Pretty cheap experiment...
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Re: Need help / Question concerning pressure in inflatable t

Post by Blacky »

smelt wrote:...

One last idea... I don't have one, but what about an aquarium pump? I know they aren't capable of much pressure, but it may be enough. Pretty cheap experiment...
The pump will be taken from a blood pressure meter. It runs at 3V (thus normal batteries will do), is small enough to be considered tiny and has the ultimate pro argument on its side: I already have it :mrgreen:

Once again thanks for the input, though! :love:
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Re: Need help / Question concerning pressure in inflatable t

Post by smelt »

"Already Have It" Wins again! It's pretty impressive, what we seem to be able to do with what we have laying around... If I put half the effort into making things around the house work, as I do making improvised toys... Wait, I sound like my Dad now.... I'm going to stop right there. Good luck, and keep us posted, I'm always interested in how things work.
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Re: Need help / Question concerning pressure in inflatable t

Post by stella78 »

Hi!
Thanks for sharing the information. I was concerned about the pressure in inflatable toys.
Thanks
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Re: Need help / Question concerning pressure in inflatable t

Post by Blacky »

Well, it's been quite a while and I unfortunately have to say I couldn't get a reasonably well working result to actually use the setup as intended. :cry:
I guess I'll have to retreat to using time to control the volume instead of the pressure, as I initially intended.

Anyways it's far better to have something that's close to what you wanted to do and doesn't injure than strictly stick to your initial plan even though it prooved to be dangerous...

I'll be back with more information once the little bugger does what it is supposed to do.

So long :hi:
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Re: Need help / Question concerning pressure in inflatable t

Post by Stretched out »

Comments about the small BP cuff pump not being enough to cause injury are completely off the mark.
Small displacement pumps are capable of creating very high pressures. A small pump is often capable of higher pressure, when compared to a simillarly built larger pump... It just takes a while to move enough fluid to create the rise.

Using water to inflate the plug could be a safer option. because should the buttplug start to leak whilst inserted, the expansion of the now un restrained water is nill (for all practical purposes). So if it takes 1ltr of water at 10psi to fully inflate the plug, should thd plug leak, you'd only have 1ltr of water entering your colon. However, if that was air, the volume would expand dramatically. Bear in mind an enema is often 0.5psi or less.
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Re: Need help / Question concerning pressure in inflatable t

Post by MKu »

Searching for informations about the needed pressure, i found this picture of an kegel perineometer pelvic floor muscle trainer (not sold anymore but drat, what a long description).
Image
The pressure gauge is measured in mmHg (as with blood pressure monitors too) with a maximum of 300 mmHg.
Interestingly, the scale of the EPI-NO Delphine Plus (another kegel trainer, still sold and used in some SM studios)
Image
has no scale unit but goes up to 30 (*10 mmHg i think).

PS: Do not forget to integrate a pressure relief valve in the last hose. Just to be on the safer side.
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Re: Need help / Question concerning pressure in inflatable t

Post by TheGentleman »

I had to look this up. Posted to save others the search. 300mmHg is equivalent to 5.8 psi.
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Re: Need help / Question concerning pressure in inflatable t

Post by Onwrikbaar »

In my Arduino-controlled inflatable buttplug (aka the "Bullfrog", see a short clip of it on YouTube), I vary the pressure between 8.8 and 17.6 kPa, or 1.3 to 2.6 PSI. A small electric pump like the ones used in blood pressure monitors reaches this pressure pretty easily, which means safety measures are definitely in order when using such a pump.
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Re: Need help / Question concerning pressure in inflatable t

Post by lj »

seeing this thread re-awaken, and the last post mentioning the potential risk of over-pressure from a blood-pressure pump, plus the unwillingness of some to take what they regard as expensive precautions, I can suggest a very simple safety system that costs almost nothing.

The item is a manometer, a techie name for a U-tube. Take a tube, any diameter, but for example 5mm internal diamater, preferably clear, and form it into a U shape. Then add water. If you apply air pressure to one end of the U, the water will displace until the difference in levels is equivalent to the pressure. In UK measures, 14psi (atmospheric pressure) is equivalent to a column of water 30 feet high, so a difference in level of 3 feet = 1.4psi. You can do the maths for any pressure.

Once you have determined the level difference for your chosen toy, just cut the tube so that level difference brings the water level to the top of the open end. Exceeding the chosen pressure will force the water out of the open end, and very quickly all the water will blow out and you now have an unrestricted exit for the air from the pump.

( I fully understand that this system can fail if a high-pressure, high volume pump is used, when the chosen tube restricts airflow and causes a back-pressure effect - in the context of the pumps being discussed in this thread, this does not apply, but of course the U-tube could be any diameter you wish, the pressure/level difference applies in all cases)
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Re: Need help / Question concerning pressure in inflatable t

Post by Riddle »

lj wrote:seeing this thread re-awaken, and the last post mentioning the potential risk of over-pressure from a blood-pressure pump, plus the unwillingness of some to take what they regard as expensive precautions, I can suggest a very simple safety system that costs almost nothing.

The item is a manometer, a techie name for a U-tube. Take a tube, any diameter, but for example 5mm internal diamater, preferably clear, and form it into a U shape. Then add water. If you apply air pressure to one end of the U, the water will displace until the difference in levels is equivalent to the pressure. In UK measures, 14psi (atmospheric pressure) is equivalent to a column of water 30 feet high, so a difference in level of 3 feet = 1.4psi. You can do the maths for any pressure.

Once you have determined the level difference for your chosen toy, just cut the tube so that level difference brings the water level to the top of the open end. Exceeding the chosen pressure will force the water out of the open end, and very quickly all the water will blow out and you now have an unrestricted exit for the air from the pump.

( I fully understand that this system can fail if a high-pressure, high volume pump is used, when the chosen tube restricts airflow and causes a back-pressure effect - in the context of the pumps being discussed in this thread, this does not apply, but of course the U-tube could be any diameter you wish, the pressure/level difference applies in all cases)
Thank you for the suggestion.
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Re: Need help / Question concerning pressure in inflatable t

Post by GeneralError »

OrgasmAlley wrote:I don't exactly have an answer to your questions as asked, but I'm happy to share my solution to what you're trying to accomplish.

I started with a blood pressure monitor like this: https://www.amazon.com/Pressure-Portabl ... ssure+cuff

As you'll probably know, in measuring BP this device will inflate a bladder inside the wrist band, and after some measurement period, release that pressure. You will find three useful things inside: a very small air pump, a small solenoid air release valve, and a pressure measuring chip. The first two are quite easy to convert to an Arduino-driven inflatable inflator. The tubing in mine was the same size as some silicone RC fuel tubing I have around. Wiring is quite simple... these are 3V devices, and I wouldn't run one from the on-board regulator. Use a MOSFET for on/off for each one.

The pressure chip is a bit more challenging. Frankly, I have not gotten around to working on that piece just yet. In theory, one can get an extremely accurate measure of the device pressure... accurate enough to see the wearer's heartbeat, obviously. However, it requires a signal amplification circuit and some playing around that I haven't had time for. Right now, my setup uses only time. I set maximum inflation based on runtime of the pump from fully deflated. Coarse and dirty, but it works.

The pump works surprisingly quickly for such a tiny device. I do not have confidence that it has much of a duty cycle, and would suggest assuming 10% to be safe.
Maybe it is a less challanging approach to not use the chip from the device but instead buy some sensor like BMP180, BMP280, BME280. They costs only a few bugs (~5 Euro). I have not worked with it so far, but with its i2c interface it should be easy to connect it to an arduino.
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