Dads is Partial Paralised need help with circuit

MrChips

Joined Oct 2, 2009
30,708
Wobble, I think you are off to a wrong start. First you come asking for help on a dubious topic.
Then you tell someone offering advice not to offer advice.

Personally, this project violates this website's TOS and should be closed.
 
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justtrying

Joined Mar 9, 2011
439
Wobble, my advice to you is this:

If you really want to help your father, find a tech school or a university that has a biomedical engineering program. Most of them have a mandatory project course within their program and/or people who would be more than happy to work with you on their own time (I know I would). This approach would cost you no money, let others learn as they work on it, contribution from you would be more than welcome and you would get a safe device in the end. As an example, my school made assistive devices for ALS patients. It was a great experience. If you have no background in making devices such as these, by no means should you attempt to do it by yourself. Good intentions are not enough.
 

spinnaker

Joined Oct 29, 2009
7,830
Even a seemingly safe non-intrusive device could create problems with a person with health issues such as the OPs father. The mentioned foot switches, while it most likely would not cause a problem for a healthy person, the same device could cause balance, circulation and who knows what other kind of issues. It is the whole reason that companies spend so much money when developing medical devices. The last thing they want to do is to make the problem worse and face a major lawsuit.
 

tracecom

Joined Apr 16, 2010
3,944
He can think for himself and will ultimately be making any decision about using what ever we can come up with.
I can imagine myself in both Dad's and Nathan's circumstance, and I recall a lot of less-than-successful experiences I have had with "medical professionals."

The one that stands out most in my memory is when my mother went to her GP, who opined that she had brain cancer. He referred her to a neurosurgeon, who called in a neurologist, who called in an oncologist, who called in...well, you get the picture. After more than a month in the hospital with countless tests and no diagnosis, I requested a meeting with one specialist after another, all of whom gave me double talk and no diagnosis, each preferring to pass the buck to someone else. Finally, in desperation, my brother sought out the radiologist, who was officed in the basement and almost never saw patients' families. Thankfully, he was completely guileless and told my brother that our mother had brain cancer and was terminal, a fact that he had conveyed repeatedly to the specialists. Mother died two weeks later.

Thus, I fully support the OP's desire to help his father, using all means at his disposal. And whatever father and son jointly decide, I say good luck to them.
 

vrainom

Joined Sep 8, 2011
126
A co-worker of mine had a wife that was dying of cancer. They mortgaged everything to seek a snake oil cure in Mexico. His wife died shortly after the treatments. While their search for a cure was well intended but did not change anything other then leaving a co-worker in debt for $30K.
That is just awful. Ripping people off out of their desire to heal their loved ones is super nasty.

Anyway, I respect op's desire to help his father, and frankly I think it's a good idea, but op should also take notice of why it worries some of the commenters. However, in a controlled environment, why not at least do some tests?

I would suggest that instead of using electrical shocks op could use vibrating motors as feedback. These ones are sealed, small and low voltage: http://dx.com/p/154245
 
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Thread Starter

wobble

Joined Jan 5, 2013
9
Your idea sounds great.

You might want to start by doing an exhaustive search to see what's already been done and what is being done now to accomplish the same thing you want to accomplish. It can save you a heap of learning the expen$ive way, and you might find some people who are working in the field that might value your input and participation.

If we are allowed to just toss out ideas as the occur to us, here goes...

I like ErnieM's concept but I would consider using pressure sensors rather than switches. The pressure measurement would be used to control the frequency of small vibrating transducers (probable range is a few Hz to perhaps 50 Hz) such that the frequency is a function of pressure. That would give your dad a sense of how his weight is distributed. I imagine that three sensors would be enough (one on the heal, and two to cover both sides of the ball of the foot).

The placement and arrangement of the vibrating transducers as ErnieM described sounds good, but you would probably have to experiment with the arrangement of the transducers with respect to location on his leg and to each other to obtain the best results.

That's my 2¢ worth.

I think your project will attract a lot of volunteers since it is likely to actually be helpful to somebody.
Thanks DickCappels, This sounds like a very promising way to approach it.
I have been reading lots of papers on the subject and most seem to go along the lines of electrical stimulation, and are directed at research for people who have lost motor control or stroke patients with Foot drop. As my dad has not lost motor control of his legs, but has lost the sensory responses from the lower leg (actually can't feel anything) and is able to walk but sometimes is un aware if his leg is touching the ground.

I understand the basics of the componets and have found some pressure sensors, but they seem to be for fluids or gas, is there a sensor for weight or applied force.
When you say that the frequency could be a function of pressure, would the vibrating transducers vibrate more due to more weight being applied?
It actually sounds very simple, but i am a novice! Is it fairly simple electronics or are we talking microprocessors?
 

wayneh

Joined Sep 9, 2010
17,496
Now does anyone know of a nice solenoid that can extend a bit to make a physical sensation of pressure?
I think a cellphone vibration motor might work and be more definitive than a gentle push from a plunger. It would feel a bit like a shock without actually being one. A problem with this strategy is the well-known phantom buzzer effect, where you think the buzzer is vibrating when it isn't.
 

praondevou

Joined Jul 9, 2011
2,942
If you want a linear feedback of the pressure from foot to ground you would be better off with a audible sound feedback. I guess it is difficult to distinguish between a 10 or 11 Hz step of a vibration sensor, but it would be very easy to recognize a step from e.g. 1kHz to 1.1kHz.

Did you think about how to physically mount the pressure sensor in a shoe? How about these LED sport shoes? I guess they use only some kind of switch maybe.

Do you actually want a linear pressure feedback or just something like ON/OFF, foot on the ground or not?

This circuit doesn't require a microprocessor.
 

Thread Starter

wobble

Joined Jan 5, 2013
9
I think a cellphone vibration motor might work and be more definitive than a gentle push from a plunger. It would feel a bit like a shock without actually being one. A problem with this strategy is the well-known phantom buzzer effect, where you think the buzzer is vibrating when it isn't.
Yes the buzzer may cause a problem, but i hope that having 3 different outputs (vibrating transducers) for each of the force senors would help mitigate this affect as positioning them in different areas would indicate rear, say back of upper leg to heel or ball of foot to front of upper leg.
Maybe the buzzers could be placed higher up the body..will need to experiment in this area i think. but we have a basic concept.
 

ErnieM

Joined Apr 24, 2011
8,377
...I understand the basics of the componets and have found some pressure sensors, but they seem to be for fluids or gas, is there a sensor for weight or applied force.
When you say that the frequency could be a function of pressure, would the vibrating transducers vibrate more due to more weight being applied?
It actually sounds very simple, but i am a novice! Is it fairly simple electronics or are we talking microprocessors?
A load sensor such as that would be a microprocessor project, something needs to read the sensor, interpet how much force is there, and drive a transducer. All that could work but I would look at a simple "proof of concept" build first, something easy to build and have dad try and see if he thinks it could help.

That's an interesting find from vrainom, the disk is 1 cm diameter and .3 cm tall if I am reading it correctly... that could be a good body transducer. Just needs an additional switch and a battery.

What switches are inside those kids shoes that flash as they walk? A metal dome tactile switch could be ideal for the switch end, but the metal tabs are hard to find: I once tried to get them but my source just gave some to me as samples, I have not found them as a normal distribution item.
 

justtrying

Joined Mar 9, 2011
439
http://www.mpg.de/4379832/F002_Focus_026-033.pdf

I have contacted the group of scientists at the Max Planck institute, they seem to be doing lots of work in the areas i described above, and have asked for there feed back on the idea.
That is the right start, I hope they get back to you. Try something local, lots of people are working on similar devices, check this out - http://www.multicare.org/home/news/...nts-device-to-help-stroke-patients-walk-again. A commercial device is out on the market as well for $6500. (do not know where you are, this is in washington)
 

DickCappels

Joined Aug 21, 2008
10,153
Increasing speed with increasing pressure makes the most sense because, if properly set up, he would not receive and input from sensors that have no or little pressure on them.

Pager vibrator motors might work well, in that they give increasing force along with increasing frequency. But would your dad want people to hear his knees buzzing as he walked? The more use you can make of work already done in this field the better.

One other comment: A wise engineer for whom I worked once said in response to my "That impossible!" comment: "Man who say it cannot be done should not stop man doing it."
 

Thread Starter

wobble

Joined Jan 5, 2013
9
I have contacted several People studying at different locations, one of the first to reply is below.
I have just ordered some micro switches and 2 small vibrating motors, this will give an idea if its going to help or even work. will let you all know soon.



Thanks for your very interesting email. If your father has lost sensation from one or both of his legs he will certainly experience great difficulty in walking and standing. If you google Ian Waterman you will come across an interesting BBC Horizon programme which describes the plight of a man who lost all muscle sensation at a much earlier age and was able, by extreme determination, to retrain himself to walk. Your father’s case may be even more difficult because A) he is older and B) he may have lost skin sensation as well and C) he may have additional problems because of his Chari malformation.

Generally, the only way of compensating for lack of limb information involves vision, so that actions which can normally be performed “automatically” require intensive visual monitoring. Ian W walks by watching his feet.

What you propose is to provide some artificial limb position or force data in the form of stimulation of a normally unassociated area of skin. This seems to me to be well worth a try. Stimulation could be electrical in the form of small electrical impulses but might be more tolerable in the form of a frequency modulated vibration. In terms of what data to encode my intuition is that pressure under the foot is probably most useful, although if there is a lot of ankle drop some reminder of ankle angle might be useful as well. The amateur robotics industry can provide appropriate sensors and so on very cheaply.



This is not really the sort of thing that I do but there are a few people who have relevant expertise. You could look at some of the papers of James J Collins (Boston Univ) who has designed such things as vibrating insoles in an attempt to bolster feedback to patients with diabetic impairment of sensation.

See for example
http://www.diabeticmctoday.com/HtmlPages/DMC0306/DMC0306_Neuro_Collins.pdf



If there is anything that you wish to pursue in terms of assessing balancing ability etc, my colleagues and I would be interested in assisting. I am copying this message to a couple of them for info. Best wishes, and let me know how you get on!



Martin



Reader in Human Neurophysiology
School of Sport and Exercise Sciences
University of Birmingham
 

luvv

Joined May 26, 2011
191
If it where me in this situation,I think my first goal would be to mechanically limit unnecessary movement in the knee and ankle via hinged brace(s).

They could serve several purposes.

A platform to mount sensors,battery,I/O,feedback(buzzers) etc.

Limiting build complexity for you and learning curve for your father.

I found some interesting products you may have already seen in your research but here they are anyhow.

http://www.ebay.com/itm/ANKLE-FOOT-...477&pid=100033&prg=1011&rk=2&sd=250694921593&

Apparently braces like this deal w/ one of the big issues of toe position,dragging.

And one that may not be as relevant to your situation but I found rather innovative and my serve as a inspiration in your project.

http://freedomlegbrace.com/Freedom_Leg_Walking_Leg_Brace.html

Anyhow,best of luck and please keep the thread updated,would love to see what you come up with.
 
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