Hello everyone,

I'll make this quick: a friend of mine suffers from SVT, short for Supraventricular Tachycardia, a condition in which the heart spontaneously starts to beat very quickly (>180 Bpm) , sometimes for many hours, due to improper electrical stimulation from the brain and heart.

There are many ways of dealing with the attacks, some more effective than others, and the techniques which help one person might not help another.

One technique that is known to help relatively consistently, however, is the application of an external pulse - typically achieved by hugging or resting with another person. By being able to feel the heartbeat of the person they're resting against, it can help to reset their own pulse rhythm, and bring it down.

Thing is, for obvious reasons, it can be hard to cuddle with someone during the middle of a day at work. So, there are devices such as pacemakers or electrode systems which can stimulate proper pulse rhythm anywhere the person is.

Thing is, because these systems are administering electrical signals directly to the muscle tissue of the heart, they need to be dealt with very carefully, and only at the recommendation of a medical professional.

This is where I'm hoping to step in.
I would like to create a device which externally "thumps" against a person's chest, simulating an external pulse, as if they were pressed up against another person, and we're feeling someone else's heartbeat.

The thing is, I have no idea what to use to generate the "thump". I can't think of any devices, mechanical or electrical, which can produce a thump, besides large, clunky motors swinging a hammer or something unwieldy.

For this reason, I am turning to you guys

I would greatly appreciate any and all thoughts or suggestions on what type of electromechanical device can be used to generate a soft but distinct "thump" against a surface. The other aspects of the device I'm hoping to create, like the peacekeeping functionality and the electrical signals and whatnot I can figure out myself... It's just the Mehanical thump that is escaping me.


So yeah, if anyone knows of anything that can produce the type of thump I'm looking for, I would love to hear it!

Thank you all for your time,
- Ty

 

Maybe a small or special version of this:

https://www.amazon.com/AuraSound-AST-2B-4-Shaker-Tactile-Transducer/dp/B0002ZPTBI

https://www.amazon.com/Dayton-Audio...coding=UTF8&psc=1&refRID=CMPEEDY9A8FVHWMFFH6B

Or this, maybe an off-the-shelf solution, just add a frequency generator and amp:

https://www.amazon.com/SubPac-M2-We...rd_wg=4V966&psc=1&refRID=CMPEEDY9A8FVHWMFFH6B

 

Maybe a small or special version of Transducer
https://www.amazon.com/Dayton-Audio...coding=UTF8&psc=1&refRID=CMPEEDY9A8FVHWMFFH6B

https://www.amazon.com/Dayton-Audio...coding=UTF8&psc=1&refRID=CMPEEDY9A8FVHWMFFH6B

Ahh yes, see my first thought was just an audio system of some sort, but the only bass speakers that could create a deep enough frequency had such large membranes that it wasn't feasible. But these, "transducers", these could be promising, im gonna look into them.


Thank you!
https://www.amazon.com/Dayton-Audio...coding=UTF8&psc=1&refRID=CMPEEDY9A8FVHWMFFH6B

 

A trick to get a puppy to sleep is to place a wind up alarm clock and a stuffed animal in the puppy's bed at night.

 

I would suggest a solenoid that imitates a heartbeat.

You will need a cradle for it to position and work against.

Perhaps between ribs on side......so one could use with desktop or floor by oneself.........but I don't know the particulars.

 

My first thought is a linear voice coil actuator: See http://www.pwr-con.com/ecommerce/products/LVCM-019-048-02.asp for an idea.

Some foot braces are made from a plastic material, so maybe that could be worn permanently. It would provide the large diaphragm.

One an event occurred, you could then attach the large actuator.

 

My first thought is a linear voice coil actuator: See http://www.pwr-con.com/ecommerce/products/LVCM-019-048-02.asp for an idea.

This looks like a promising lead as well. My only concern is that I won't be able to get an activation rate of 180 Bpm or more, given the time it'll take for magnetic fields to switch and reverse the motor, but it's definitely something I will look into. Thank you!

 

Voice coil activation is really fast. They were used on disk drives the size of washing machines.

It might be power hungry.

I'm not sure you want to say match the beats initially and then ramp them down to a safe level?

So, the idea is to wear the large diaphragm and then, maybe slip something in place.

Here http://www.jameco.com/z/6ZK003-R-Vibrating-Motor-1-3-Volt-DC-80-mA_256306.html is a "vibrating motor" which maybe a place to start as well. Something having some sort of end that runs at 180 RPM to say 80 RPM and "thumps or hits" the diaphragm mounted on the chest.



I think even a motor, e.g. servo motor, might be able to "thump" the diaphragm.

There are rotary solenoids too. Here is just one search result. I used Ledex rotary solenoids for a design. They operate very quickly, but probably not 180 times a minute.

You can actively turn off a coil to make it faster.

You can also think like a "hammer".

Bone conduction headphones might even be a better place to start. See https://www.everydayhearing.com/hearing-technology/articles/bone-conduction-headphones/

 

A cradled fixed coil of wire around a large cylindrical super magnet......should make a good thumper.

 

This strategy assumes that the communication of mechanical energy is what provides the stimulus. Do we know that's true? There could be some electrical communication if there is skin-to-skin contact. There could even be audio communication.

My mechanical idea is to rotate a cam at roughly 60rpm, and let that cam rub against a plunger, similar to the way a camshaft pushes your engine valves. The cam would be shaped to simulate a heartbeat and just moving the plunger would produce vibration. Somehow you'll have to knock down all higher frequencies. The motor will run faster than the cam, so you'll need a gearbox.

I guess it wouldn't be too hard to convert a speaker into a direct-contact actuator, like those butt thumpers they sell to mount to your easy chair. Or just buy one of those.

 

KeepItSimpleStupid,

You're exactly right with your guess, im planning on starting the device at whatever heartrate the person suffering the anxiety attack is at, which can be up to 240 bpm in extreme cases, and then crank it down from there by 10bpm every 20 seconds or so.

The hesitation I have with using a motor or servo that swings a hammer to hit a diaphragm is that the hammer will need to reset before each strike, requiring effectively 480 motions per minute as a max, and I think this will create so many secondary vibrations that it would drown out the actual pulse. I will look into the linear actuators, though, for if I use maybe two side by side I can cut down the activation rate to a max of 120 bpm, by alternating the activations.

Thanks!

 

A cam would be complicated, an off-center weight attached to a regular DC motor would go thump, but for effect at low RPM you might need a heavy weight..

 

I'm leaning towards those things you can attach to a piece of furniture or a window to turn it into a speaker. You really don't need much power to replicate the heartbeat of a person you're hugging.

 

How about an air powered jack hammer?

 

Has anyone tried seeing if just an audio recording of a steady heartbeat played through earphones does the trick?

Do you have evidence that matching the high rate and then ramping down does anything? After all, when someone hugs someone else to address the problem the other person's heart doesn't start out at a matched, high rate?

 

Has anyone tried seeing if just an audio recording of a steady heartbeat played through earphones does the trick?

Do you have evidence that matching the high rate and then ramping down does anything? After all, when someone hugs someone else to address the problem the other person's heart doesn't start out at a matched, high rate?

Hearing a heartbeat does have an effect, but its relatively minor, especially considering the patient can often hear their own racing pulse. Also, no, there's no evidence that matching the rate first will help more, because as you said when hugging a person this isn't the case. However, my thinking is that by having the heartbeat synchronized at first, it helps with, well... i guess the best word would be "immersion". If the external pulse doesn't match your own, it feels weird, since you have basically two competing heartbeats creating a beat frequency. While it does still help calm the patient, im thinking i can achieve the same effect faster by starting off synced.

 

I'm leaning towards those things you can attach to a piece of furniture or a window to turn it into a speaker. You really don't need much power to replicate the heartbeat of a person you're hugging.

I'm leaning towards proper and immediate medical help.

https://www.google.com/search?q=Sup...-8#q=supraventricular+tachycardia+treatment&*

Having an unnecessarily high and irregular heartbeat that can go for hours at time due to what is clearly a high level anxiety attack and or other even more serious medical issue is not something I would be treating with homebrew DIY electronics gadgets.

Or you could just taser them (on low of course) and see what happens.

 

I'm leaning towards proper and immediate medical help.

https://www.google.com/search?q=Sup...-8#q=supraventricular+tachycardia+treatment&*

Having an unnecessarily high and irregular heartbeat that can go for hours at time due to what is clearly a high level anxiety attack and or other even more serious medical issue is not something I would be treating with homebrew DIY electronics gadgets.

Or you could just taser them (on low of course) and see what happens.

Unfortunately there's only two known effective medical treatments, but both are quite invasive and can have many complications. Pacemakers are the first, and I dont think i need to explain the ups and downs of those, and the second is a radio-frequency treatment which literally destroys certain electrical pathways in the heart muscle tissue. Again, I don't think i need to explain the risks inherent in that. Granted, the technique is remarkably successful (>90%), but still, for some, there are no treatments for SVT, only coping mechanisms. That's all I'm hoping to construct here -- something that may bring relief during an episode, not a cure.

 

Have you ever held a actuating solenoid in your hand?

 

Ahh yes, see my first thought was just an audio system of some sort, but the only bass speakers that could create a deep enough frequency had such large membranes that it wasn't feasible.

Why not? Are you looking for something portable, worn all the time like a vest; or a device you go to and use when necessary, like hugging another person?

ak