Automatic electric stimulation concern

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Kurbak
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Automatic electric stimulation concern

Post by Kurbak »

Hi all, I have a setup for automatic electrical stimulation but am concerned I may be doing something dangerous.

I have a standard TENS machine, which I have hooked up to a relay switch. I turn the TENS on, then can turn the relay on or off to control the current to the TENS pads.

What I have noticed, though, is the TENS seems to "store up" current, such that the first shock is very powerful. This even happens when the settings are very low.

It feels like all of the shocks which aren't being delivered are being stored and all released at once when I flick the switch/relay I have put in.

Has anyone else experienced this? Is there a way to avoid it, with the setup I have?

I am not planning to use it in this way again, which is a pity as I was pleased with the setup.
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Shannon SteelSlave
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Re: Automatic electric stimulation concern

Post by Shannon SteelSlave »

Welcome to Bound Anna, Kurbak. I am not as experienced with the TENS this way, but someone should be along to help you, so check back soon.
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Re: Automatic electric stimulation concern

Post by kinbaku »

Welcome Kurbak,
Have you connected a capacitor in parallel to the relays?
It could be the coil of the relay causing this. Check this post regularly, there are members who have more experience in this than me.
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Re: Automatic electric stimulation concern

Post by Riddle »

You are experiencing a capacitive shock like from a capacitor. The problem is putting the relay on the output.

The solution is to put the relay in the power input wire off the 9V battery.
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Re: Automatic electric stimulation concern

Post by occorics »

Probably a current spike, because the load is suddenly changing.
I'd try to put a resistor into the signal line to limit the current. In case it dampens the signal too much, it could be bridged with a 2nd relais after a moment, just like soft-start circuits for power-amps do.
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Re: Automatic electric stimulation concern

Post by KinkInSpace »

There are a few things here that we need to be aware of.

Yes, this can be a bad design where electricity is stored wrongly causing a big jolt. I have to feel it in order to know, but in such situation, I really don't want to for obvious safety reasons.

Another thing that you cannot overlook is the following:

The human nerves are very interesting when it comes to stimulation.

You stimulate the nerves, and the brain then calibrates the system to deal with this. The system is not quick, but there is an obvious difference between no estim and estim. If you do estim on a low setting, but you go from nothing to that low setting, the body is not used to this, and that initial spike may feel very harsh as the body is not expecting it. It will adjust quickly and as a result, the estim feeling weakens to what it is supposed to feel like.

The reason is also that the muscles will tense up which helps coushening the estim. If muscles tense up from nothing to a lot of electricity, it can actually do damage to your muscles, such as strain them, which obviously causes pain. So you may be experiencing a combination of both.

Keep in mind that if you have estim on a low setting, then slowly raise the estim to higher levels using the unit itself then choose to pause the estim (I have a powerbox with pause function), the longer you wait with resuming the estim, the more your body has readjusted to no estim, and thus the harsher the shock will be when it resumes, especially if you increased to a higher setting. If I unpause after 15 seconds, its still pretty doable. If I do it after 30 I'm getting in painful territory. If I'm going past 30 seconds I always just stop and restart.

Most powerboxes that have a dedicated pause/resume do a fade-in on restart such that it is not a complete shock. This makes it safe for your muscles, but it will still feel very overwhelming when you resume to that high level after 30 seconds of nothing.

I would definitely recommend you to get a proper powerbox that supports the function you're trying to build. The DG-Lab Coyote, although expensive, has everything you want and need, and more. Especially if you combine it with xtoys.app. There's a script that is a very evil tease and torture script that basically does what you describe. It teases you with low estim, ramps up to more intense levels and goes down again, then finds moment of complete absense of estim, waits just long enough to get you on edge, and shocks the crap out of you. Combine this with an auto-intensify script, where the intensity slowly increases, and you can have hours of fun, giving you enough time to feel little to nothing as you setup your bondage, and be in agony lateron in the session where you want out with a big smile on your face. :)
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Re: Automatic electric stimulation concern

Post by lj »

I agree with Kinkinspace - the OP may well be experiencing the result of perception of the stimulus, rather than its amplitude.

I obviously can't speak for the OP's TENS, but I recall testing mine with an oscilloscope - the pulse train is absolutely regular from the first pulse onwards. The circuit in my TENS uses a square-wave pulse generator feeding a transformer - this produces a voltage spike on the output pads, the frequency is determined by one control, and the amplitude by the other control - this latter control simply makes the "on" square wave pulse wider or narrower, which means there is more current flowing through the transformer, hence a bigger pulse. Yes, there is a storage capacitor involved, but it is on the primary side of the transformer, so will only "store" current for one pulse at a time, and it doesn't "know" that was the first, second or any pulse.

However, and I know from personal experience :shock: that the start of a TENS pulse or burst of pulses is much more severe than the following pulses. That is simply the perceptual change from "no stimulation" to "ouch!"

There is another factor involved. A nerve "fires" its signal ( a pulse of electricity in effect) down the nerve channel, using a (very complex) biochemical reaction and cell membrane transfer, and this depletes the ability of the nerve channel to function over time. Pain causes an impulse from the sensing cell to be generated, and passed to the next nerve cell and so on to the brain, but over a short time (tens of milliseconds) the ability of the nerve cell to fire is reduced or even stopped. So the first TENS pulse will result in a successful firing of a series of pulses proportionate to the "pain level". If the TENS pulses continue at the same rate, they may well deplete the nerve cells' ability to transfer the pulses, so the message the brain gets is "not so painful"

Microprocessor controlled Electro-Stimulators can bypass this effect by varying the amplitude of the pulses, for example by starting low, and rising over time, or, of course, sending bursts of high pulses with enough time between bursts to allow the nerves to recover and fire fully and therefore feel more painfull (also personal experience :shock: )

We can leave the production of endorphins out of this, as this is a slower process, though very enjoyable...
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Re: Automatic electric stimulation concern

Post by KinkInSpace »

Very well said lj. :) Could not have said it better myself (which is why I didn't...) :rofl:
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Re: Automatic electric stimulation concern

Post by Kurbak »

Thanks all, interesting stuff.
The magnitude of the shock, in this case, felt much worse- to the extent that it is hard to believe it's a body response trick. Still could have been, but feels unlikely!
I tried again with the tens at its lowest setting, barely perceptible- and the initial shock was still severe (although less so). It then settles back to the background of being barely there.
I will have to look up other options, or move to a safer method of stimulation, as this sounds more complex than I gave it credit for.
Thanks again everyone!
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Re: Automatic electric stimulation concern

Post by rexter »

KinkInSpace wrote:I would definitely recommend you to get a proper powerbox that supports the function you're trying to build. The DG-Lab Coyote, although expensive, has everything you want and need, and more. Especially if you combine it with xtoys.app. There's a script that is a very evil tease and torture script that basically does what you describe. It teases you with low estim, ramps up to more intense levels and goes down again, then finds moment of complete absense of estim, waits just long enough to get you on edge, and shocks the crap out of you. Combine this with an auto-intensify script, where the intensity slowly increases, and you can have hours of fun, giving you enough time to feel little to nothing as you setup your bondage, and be in agony lateron in the session where you want out with a big smile on your face. :)
I'd like to be able to program a set of parameters and durations that execute in sequence. Do you know if this box or any is able to do that?

I almost envision a scripting language:

Code: Select all

[block A]
channel=
freq=
shape=
intensity=
duration=

[block B]
channel=
source=[some mp3 @some time index]
duration=
with the main loop just selecting blocks to execute. could be from a fixed sequence, randomly, or other method that might depend on the state of some detector.
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Re: Automatic electric stimulation concern

Post by Shannon SteelSlave »

Good to meet you, Rexter. Send me a Private Message, we may be able to use your talents elsewhere in this forum.
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A Jedi uses bondage for knowledge and defense, never for attack.
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Re: Automatic electric stimulation concern

Post by Keyless »

What KinkinSpace and IJ have written might well be the reason for what you observe. I think there is another possibility. It might be acting in combination with the effect those honourable members describe.

From what I understand, you have put the relay in the leads to the electrode pads. The reason for what you are seeing could be deep in the design of the machine. Everyone talks about voltage, but when it comes to electric shocks, current and duration are important. Voltage and current through a resistance are related by Ohms law. Voltage=Current x Resistance. The resistance between the electrodes connected to a human being varies considerably. Good quality TENS machines have a feedback system which adjusts the voltage such that the current is controlled at the required level whatever the resistance, subject to some maximum allowed voltage limit. If you disconnect the electrodes the machine may think the resistance has gone very high and increase the voltage, probably to the upper limit. I think I would expect a good machine to remove the voltage completely in response to the electrodes being disconnected, but maybe not. If the voltage is not removed, when you reconnect the electrodes the feedback system will rapidly re-adjust the voltage. Even so, the high voltage might be present long enough to give you a jolt. There is a better explanation of the above in this article: https://www.quellrelief.com/wp-content/ ... 01_Web.pdf see in particular the section under “intensity control”.
Can you arrange to turn the whole machine on and off rather than disconnecting the electrodes?
I am not saying this is definitely the reason for what you are experiencing, but it seems quite possible. Whatever you do, be careful.
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Re: Automatic electric stimulation concern

Post by KinkInSpace »

rexter wrote:
KinkInSpace wrote:I would definitely recommend you to get a proper powerbox that supports the function you're trying to build. The DG-Lab Coyote, although expensive, has everything you want and need, and more. Especially if you combine it with xtoys.app. There's a script that is a very evil tease and torture script that basically does what you describe. It teases you with low estim, ramps up to more intense levels and goes down again, then finds moment of complete absense of estim, waits just long enough to get you on edge, and shocks the crap out of you. Combine this with an auto-intensify script, where the intensity slowly increases, and you can have hours of fun, giving you enough time to feel little to nothing as you setup your bondage, and be in agony lateron in the session where you want out with a big smile on your face. :)
I'd like to be able to program a set of parameters and durations that execute in sequence. Do you know if this box or any is able to do that?

I almost envision a scripting language:

Code: Select all

[block A]
channel=
freq=
shape=
intensity=
duration=

[block B]
channel=
source=[some mp3 @some time index]
duration=
with the main loop just selecting blocks to execute. could be from a fixed sequence, randomly, or other method that might depend on the state of some detector.
The DG-Labs Coyote does this straight out of the box.

You have 20 or so patterns and you can add more. Then you can select which of these patterns you want to use in your session as a playlist or at random. You can select how long each pattern plays before going to the next.

Then you have the Smart Auto Increment settings where you can make the intensity change to a random value between its current intensity and any value between 0 and 20 higher than that it was with a duration for how quickly the next jump is. Next there is the setting that slowly increases the intensity.

Then there are the auto on and auto off timers and there's even an initial delay setting now, so you can set an intensity, start it, wait and then all fires up.

If the patterns are too basic, you can actually use one MP3 file and do stimulation as the mp3 plays instead of the patterns. (mp3's can be created and stitched together using an audio editor on your pc!)

If that is still not enough, there is a scripting possibility using xtoys.app with pre-written scripts. Do note, writing scripts here is not easy and a bit counterintuitive for a programmer. Its more an event-based block scripting system than an actual language. So if you are familiar with MultiMedia Fusion, Games Factory, Unity or other game engines that work with events, then xtoys.app is going to be easy.
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Re: Automatic electric stimulation concern

Post by Sashauk »

Personally I don't think it's anything to do with the set-up as the relay is only being used a a switch and it's coil is entirely separate.

As someone who has used a TENS device for medical reasons I can confirm that there is definitely a perception situation when using one. The purpose of a TENS device is to numb the nerves to reduce the pain being felt, so obviously when one is using one whatever part of the body it is being numbed by the electrical pulses. The first shock is always going to be the most intense as after that the nerves are less sensitive to further shocks.
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Re: Automatic electric stimulation concern

Post by muestrom »

I know this is very old, but I would try to connect the relay in parallel to the electrodes, i.e. short circuit the electrodes, since these units try to deliver constant current, not constant voltage.
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