Neuromuscular Electrical Stimulator

[septer012]

NeuroMuscular Electrical Stimulator

I participated in Student Design Compitition, this is what I came up with in 3 days.

Neuromuscular Electrical Stimulation (NMES) is a non-invasive, non-addictive means of muscle rehabilitation after injury, surgery or disease. Patients with a wide range of orthopedic and neurologic diagnoses can benefit from NMES, which applies customized electrical stimulus to cause a muscle to contract. “The major benefit of integrating NMES in the treatment of patients is the reduction of total rehabilitation time and concomitant reduction in the total cost of recovery.” (Electrotherapy in Rehabilitation, Meryl Roth Gersh, 1992).

The device will have two output channels that can operate in three different modes of operation (stimulation): Synchronous, Constant or Alternate.  The main focus of the design is on the power circuit,  control circuit and the amplifier circuits for outputting the appropriate signals at the appropriate and predefined  (by the user ) waveforms and intensities.  The purpose of this design is the challenge to build a lower cost NMES machine comparable to what is on the medical market (©EMPI $1500.00).  The hardest part of the design is to create an output signal that is linear and not stepped for precision and comfort to a patient.   The basics treatment of this device is that it should be a handheld device and easily useable from a medical practitioner like Doctor of Physical Therapy or a home user with just a brief usage training.

 
PROPOSAL

FULL REPORT

FULL SCHEMATIC

[Dago]

That looks like a great design, and THREE days, thats fast!

You can btw. add new components/symbols (you were missing the MAX668) pretty easily in eagle.

[septer012]

Thanks, I haven't had time to learn how to make parts in Eagle.  I need a nice set of digital calipers then ill practice on parts I have on hand.

[GeekGirl]

I rarely need callipers, all the parts I have ever used have datasheets online, in the datasheet you will find (usually near the end) the recommended PCB footprints. If you are using a software that has a footprint wizard (eg altium designer) the manufacture also provides the part with all the dimensions

[septer012]

Alright, I Placed 3rd of 15 different students/student design groups.    There was some Pre-PH.D guys there placeing behind me w00tz

[Simon]

for those interested in this kind of alternative medicine there is a device called the skenar which was designed in russia over 20 years ago, it was a military projec that then went comercial, the idea was to use it in space and eliminate medicine so that there were no problems recycling water on space stations.

I have one of these and they do certainly work miracles. the key to it is feedback. not read all your report but it looks along those lines ?

[septer012]

Similiar in the fact they both make use of the nerves of a user to stimulate.   Dissimilar in the fact that the skenar device uses bio-feedback.  NMES has a distinct purpose,  to fire an inactive muscle.   TENS has a distinct purpose for transcutanious pain relief.  One is a medical device.  Where-as I believe the skenar is very much just like those ab simulators that have little to no  scientific research or backing.  (now I dont mean it in a way to say it isnt a good device, I mean it in the way that why should the general public need one?)

[Simon]

The skenar is far more effective and well proven than you think ! its not mambo jumbo and does work, it has helped cure most things and will do just what your device does and much much more. essentially the skenar is a tens machine with feedback so instead of just providing a signal that may or may not be of use it adapts to suit the condition. this also means that ot remains effective as the body will become imune to the same ginal non stop the same as some drugs become ineffective over time.

you want to know why the skenar is not used more widely. well think, firstly its one of those things that not everyone beleives in, it does rely on you actually expecting it to work, this is because the skenar DOSE NOT cure you, it gets you imune system working and "onto the job", if you have decided that it is useless then fine you have just told your imune system to shut down and of course nothing will get it going. the results of course do vary from person to person but hey, isn't that the same with drugs ?

Think what would happen if we suddenly needed only a fraction of the drugs we currently do ? the medicine industry is huge and I'm sure that many people in power have a stake in these companies. It would mean big losses for them and needless to say doctors.

[septer012]

The skenar is far more effective and well proven than you think ! its not mambo jumbo and does work, it has helped cure most things and will do just what your device does and much much more. essentially the skenar is a tens machine with feedback so instead of just providing a signal that may or may not be of use it adapts to suit the condition.

How does it take feedback from the human body?

[Simon]

I don't know exactly as the workings have not been explained to me and I'm not taking apart a device belonging to my father which costs £ 1500. The instructions do say that the machine evaluates its effect based on the change in skin impedience. so I would guess that there is some sort of current measuring circuitry to see how much current the skin absorbs, the more it does the lower the impediance of the skin I expect

[Brett]

Congrats on 3rd place.

As someone who has successfully designed, manufactured, FDA 510(k) submitted several electrotherapy devices with interferential and high voltage galvanic modalities, I can say you definitely have a ways to go before you can compete with those "no name" companies.  I can't really give you any pointers, or I'd be violating my own company's NDA... but keep at it and you'll get there.  Tested device in-hand is one thing... selling that voodoo magic is quite another.

BTW: $1500 is cheap!  Try $2499   Actually, this is mainly the MSRP street price... and there are so many layers of distribution and sales built in so that everyone makes some money.  Nobody in their right mind would pay $2500 out right for one of these devices... but in layers... ahhhh, smarter.   Even your device would sell for $1500 by the time it exchanged hands enough, once you got it fully designed, validated, FDA approved,mfg'd and marketed.  Too bad this market is not as good as it was back in 1999-2004.

[septer012]

Was I anywhere close to a good or logical design?

[Simon]

I think that with something like this you are looking at needing a lot orf medical understanding, you are designing so0mething to interact with the body bot some machine which you have decided will have a certain effect. apparantly the skenar machine was developed on acupuncture, I'm not sure how they translated acupuncture to an electronic process but whatever they did it was certainly successful.