retrofitting an auto-mute volume control?

[Jon Kirwan]

To start off, I'm not looking for a specific design, though of course
I will be very happy for any such attempts. I'd like some thoughts
about approaches or problems I may need to consider. I'd be happy to
then expose some design I come up with, to criticism.

I need an auto-mute circuit that I can use to retrofit devices that
provide an amplified audio output to a speaker or speaker pair. These
include television sets which use UP/DOWN buttons to set volume all
the way to resistor-based knobs and wheels that set volume.

I could consider not "getting everything" and instead just focusing
only on those devices which use a resistor to control the volume,
interceding at that point (using the existing control but adding a
circuit around it.) In that case, the circuit would need to behave
the same regardless of which resistive 'end' was used to set the
highest volume. I'd like to handle TV sets that use UP/DOWN buttons,
too. But even _some_ solutions are better than none.

By 'retrofit' I mean that I cannot add new control systems to existing
ones by drilling holes and making the operation more complex to handle
-- the operation must be fully automatic and set by me _before_ I open
up the units and insert the circuit, without having to create any
external access holes or buttons, etc.

My daughter has grand mal seizures that my wife and I need to hear the
beginnings of. My daughter loves to turn on stereo systems and music
boxes, quite loud at times. She enjoys listening and often has her
computer software playing something loud while having a CD player
playing something else in the same room, while still something else is
playing on a CD player in the next room, as well. We don't want to
take that away from her, but it also makes for a noisy environment
which can easily mask our ability to detect a seizure as early as we'd
like to. The results of our missing the early sounds of a seizure
event could potentially lead to broken arms, or even death in an
extreme case. So this can have very important consequences.

We've used timers on the power plugs. But besides the fact that she
moves things around from place to place if it "doesn't work" from her
point of view, using a timer greatly complicates our own life. She
needs to have the ability to initiate the operation by using controls
that already exist on the device. (She is 25 years old, but operates
much like a 4 year old. She can learn some things, like how to turn
the volume control knob, but using timer boxes greatly complicates
operation and thus greatly complicates both her and our lives.)

What I need is something that doesn't increase the complexity of her
use of the device. She simply needs to learn to "adjust the volume"
as she always does to cause the mute operation to cease, instantly.
But that action should initiate the start of a new timing cycle. The
auto-mute effect needs to take place after about 10 minutes of use,
but I'd like to be able to set that range from perhaps 1 minute to 15
minutes. That said, to be completely honest about it, I could live
with a fixed 10-minute delay.

The power source is an issue. These devices I'd modify _do_, of
course, have internal power supplies and I could scarf around to find
something to attach to, of course. How the ground will relate to the
speakers, I don't know. It may depend on the device. The speaker
outputs may even be galvanically isolated. Best would be that energy
is derived from the sound system's own delivered power to the
speakers, so that it's 'universal' in that regard. This would save me
from replacing batteries or having to make custom designs for each and
every situation's internal supply modifications. (While the voltage
is building up in such a case, though, I'd like the unpowered circuit
situation to be 'unmuted.') But battery powered, if necessary, is
acceptable if I don't have to replace them more often than once every
few months and so long as I'm able to fit the battery system inside
(in some cases, that will be 'hard'.)

What would work best for her is that if she 'fiddles' with the volume
control, the mute operation ceases and the timer starts.

This needs to work on CD and karaoke players, stereo and mono
amplifiers, TVs, etc. Almost all are wall-plug powered. Not all,
though. Some use multiple D-cells ('boom boxes') or allow an
'either-or' operation, using batteries if unplugged from the wall.

I've only just begun to think about this and my own limitations in
experience are suddenly in evidence to me. My first thought would
only work on the resistive type controls, would use a micro to monitor
the value (ADC) and then control a digital POT I select. It would
need power but I could use an MSP430 to mitigate that problem, using a
small CR2025 or CR2032 which would last quite a while. (The timing
requirement of minutes, alone, almost forces me to think in terms of a
micro, though I can think of a few analog circuits using a cap and
mosfet that would handle such times.) I would probably need custom
programming, a tweak for the input gain perhaps, and perhaps a
different digital POT for each unit I modified. But at least I can
see how to handle that.

Thoughts and criticisms meant constructively are appreciated.

Jon

 

[Jon Kirwan]

This is not a technical problem. It can't be solved by any technical means.

I'm not sure what problem _you_ are talking about. The question _I_
asked can be addressed from a technical perspective, at least in
piecewise fashion. If you are referring to the larger problem of life
itself and the issues we as a family face, I wasn't asking for a
solution to that.

Jon

 

[Jon Kirwan]

THAT Corporation makes nice AGC/MUTE chips with compression/expansion/
log detection.

www.thatcorp.com

A little too 'jazzy' a web page, for one thing. I'd be fine just
building a micro to handle the ADC-to-digipot thing, so if the
offering is more expensive or has a longer learning curve for someone
used to doing embedded stuff, I may pass. At least, I'd know I'd get
exactly what I needed, doing it by hand.

Anything there you wanted to draw my attention towards?

Jon

 

[Jon Kirwan]

Not sure if it helps....

On the cd player at least, power it via one of those pneumatic timer
switches often used to control stairwell lights in apartment blocks. You can
adjust the time delay on them. Not sure of the run time range. Nice &
simple.

Use to enable power or audio path. Just press the button in and the thing
will run for the time set.

something like:

http://www.tlc-direct.co.uk/Products/EK400A.html

That violates what I was talking about earlier. I'd like to avoid
complicating what is already enough for her to learn to use and the
units need to remain powered (the computer still running, for example,
and not shut down), which is why I was looking for a timed 'mute'
capability and not a complete power-off function. I've got a box of
something almost exactly like those. (A few have been applied
elsewhere, where they do help me -- garage lights, for example.)

I appreciate the thought. But been there, tried it, and am still
looking to make mods for her. What I discussed is exactly what I'd
like to do -- have the volume control initiate a 10-minute enable for
the audio, returning to a mute state afterwards without powering down
the system. At least, that's what's needed in _some_ cases.

I have two ideas I plan to try out in a few weeks when I get some
off-time to try them. Looking for more.

Thanks,
Jon

 

[Mark Zenier]

I need an auto-mute circuit that I can use to retrofit devices that
provide an amplified audio output to a speaker or speaker pair. These
include television sets which use UP/DOWN buttons to set volume all
the way to resistor-based knobs and wheels that set volume. ....
What I need is something that doesn't increase the complexity of her
use of the device. She simply needs to learn to "adjust the volume"
as she always does to cause the mute operation to cease, instantly.
But that action should initiate the start of a new timing cycle. The
auto-mute effect needs to take place after about 10 minutes of use,
but I'd like to be able to set that range from perhaps 1 minute to 15
minutes. That said, to be completely honest about it, I could live
with a fixed 10-minute delay. ....
Thoughts and criticisms meant constructively are appreciated.

How about:
1) proximity switch that detects the hand or finger near the control.
(thin foil sense electrodes under adhesive film around the control?)
2) capacitive displacement sensor where you could add a vane to the
pot. shaft inside the box that detected change of position.
(same circuit as #1?)
3) button press detection, either sensing levels on the existing button
or a touch switch overlay, or a second switch inside the case.
4) for units with a remote control: an IR receiver, or tap on the
existing IR receiver module, or detecting the flicker on the visual
feedback LED that most stuff seems to have, these days.

Mark Zenier [email protected]
Googleproofaddress(account:mzenier provider:eskimo domain:com)

 

[Jon Kirwan]

Are you not approaching this from the wrong perspective?

I certainly could be.

Long ago I had something to do with seizure detecting equipment in some hospital.
Some guy had designed a system that monitored the beds by having a contact that would
make if there was strong vibration, and the contact sequence was monitored for a specific
pattern to give an alarm, and start a video tape recorder.
The staff could then react on the alarm, and later study the recordings.

My wife and I have discussed this. In fact, as late as this morning.
More on that in a second...

So I wonder if you could make her wear some gadget with a some
vibration sensor that would send a wireless alarm,

We were, in fact, talking about having her wear some kind of wrist
bracelet. However, there are complications. One of them is her own
willingness. I cannot express to you just how difficult it has been
to get her to do so much as wear underpants. She is highly sensitive
to 'touch' on her skin. We fought for years and years, almost minute
by minute in battles with her, over things like this. Even today,
getting her to keep something on will be _very_ difficult.

I'm not saying 'impossible', as this is something we did talk about
today and could consider as an option. But it probably won't be easy
to design for her sensitivities, let alone it's technical function.

One last thing, transmitters use lots of power. Even receivers do
(though that can be mitigated by powering up and powering down between
selected intervals.) A solution that would work (as you will see why
in my next comment) is to avoid a transmitter of any kind and instead
use a piezo tweeter that we'd hear. However, there may be false
positives and these will 'drive her nuts.' I need to work on that
aspect so that what sound is made is okay with her, but noticeable to
us. I can do that.

if needed with GPS position, to you or some help agency?

That's not needed. We are here with her, 24/7. It's what we do. She
is never more than 50' from one of us. Not ever more, for any time.

That would be more rest for you, and more reliable.

Perhaps. It would not abate the noise level, which has other (less
important) consequences. But you are right that it is worth
considering closely.

However, there is another consideration. Detection. I've watched
many times while she stands upright, suddenly goes completely stiff
like a board (no noticeable vibration, body-wise, but a gasp of sound
that escapes for a moment from her because of the sudden lung pressure
change) for perhaps 10 seconds or so and during which time she loses
balance and simply falls over onto whatever is there. (We catch her,
if we are close enough to get there, of course.) Detection is going
to be difficult. I don't mind some false positives, though. We
already deal with plenty of those just from our own constant worry.

The trick IIRC was in the detection of the sequence.
Yes.

But in that system I worked on there was no micro, in those days, a
modern small micro like a PIC could
easily be programmed to detect specific sequences, say spectra.

I could, over time, develop data on the variety of her responses and
select out portions of that and use cross-correlation for detection, I
suppose. There are other approaches, too. But I would have to do a
lot of data gathering to detemine what works best for her. It's
possible that in the process I may develop something more generally
useful. That would be a side benefit.

Maybe wear it on the arm, or on a belt?

Lots of possibilities. Thanks for thinking with me about this. Much
appreciated.

Jon

 

[Jon Kirwan]

By the time you hear the sounds, it might be too late to avoid broken
arms. But at least to have early treatments.
<snip>

This is always an issue with us. We move quite quickly when we get a
sound we recognize. Many times we are able to catch her before she
reaches the ground, as she stiffens and it takes a few seconds for her
to topple if she is standing at the time. (She doesn't fall like a
rag doll, though she might be in a precarious orientation that can
fall as quickly.) Sometimes, it happens while she is laying down --
some of which we believe is because she can sense something wrong
beforehand -- though we cannot ask her as she has no language for
that.

What's important here is that we hear _better_ so that some of those
occasions we don't hear right away are heard earlier and that gives us
a chance to mitigate effects. For example, although we have removed
the possibility now there was one time where she trapped an electric
space heater between her legs during a seizure. It did shut off as it
should (tip sensor), but it was still quite hot on parts of the
surface. And as you can imagine, this led to inner thigh burns.
Getting there quickly meant less damage than otherwise.

So very definitely every single second of improved response time
counts. It can mean the difference between life or death, ultimately.

Jon

 

[Baron]

I certainly could be.


My wife and I have discussed this. In fact, as late as this morning.
More on that in a second...


We were, in fact, talking about having her wear some kind of wrist
bracelet. However, there are complications. One of them is her own
willingness. I cannot express to you just how difficult it has been
to get her to do so much as wear underpants. She is highly sensitive
to 'touch' on her skin. We fought for years and years, almost minute
by minute in battles with her, over things like this. Even today,
getting her to keep something on will be _very_ difficult.

I'm not saying 'impossible', as this is something we did talk about
today and could consider as an option. But it probably won't be easy
to design for her sensitivities, let alone it's technical function.

One last thing, transmitters use lots of power. Even receivers do
(though that can be mitigated by powering up and powering down between
selected intervals.) A solution that would work (as you will see why
in my next comment) is to avoid a transmitter of any kind and instead
use a piezo tweeter that we'd hear. However, there may be false
positives and these will 'drive her nuts.' I need to work on that
aspect so that what sound is made is okay with her, but noticeable to
us. I can do that.


That's not needed. We are here with her, 24/7. It's what we do. She
is never more than 50' from one of us. Not ever more, for any time.


Perhaps. It would not abate the noise level, which has other (less
important) consequences. But you are right that it is worth
considering closely.

However, there is another consideration. Detection. I've watched
many times while she stands upright, suddenly goes completely stiff
like a board (no noticeable vibration, body-wise, but a gasp of sound
that escapes for a moment from her because of the sudden lung pressure
change) for perhaps 10 seconds or so and during which time she loses
balance and simply falls over onto whatever is there. (We catch her,
if we are close enough to get there, of course.) Detection is going
to be difficult. I don't mind some false positives, though. We
already deal with plenty of those just from our own constant worry.


I could, over time, develop data on the variety of her responses and
select out portions of that and use cross-correlation for detection, I
suppose. There are other approaches, too. But I would have to do a
lot of data gathering to detemine what works best for her. It's
possible that in the process I may develop something more generally
useful. That would be a side benefit.


Lots of possibilities. Thanks for thinking with me about this. Much
appreciated.

Jon

Just a wild thought... Video surveillance with motion detection.

 

[Jon Kirwan]

From recent discussion in c.a.e:

http://tinyurl.com/yg4ogn8

This thing can be turned into a wearable monitor.

When I first read your response here, my mind immediately went to the
TI watch mentioned in CAE. I first read about it in the Yahoo group
for the MSP430, of course. And I looked closely at the possibility at
the time. I'm still considering it. However, I have spent quite some
time working with her to wear a watch of any kind, to no avail. She
is fascinated by them and loves to take my watch off and put it on.
She likes the details of doing that. Sometimes, if she notices I
don't have it on she will ask me, "Watch?" But I've been unable to
get her to wear one for more than perhaps a few seconds. And I've
tried. Hard.

So, tempting as it is and as much as I appreciate your noticing this
and bringing it to my attention (it was a _smart_ thought), I'm still
struggling about the her response to it.

That said, I had already ordered the US band version on the
possibility. I'll need to do data gathering first, then consider what
analysis of it shows me. I am still not sure what data will be
available. As I mentioned elsewhere, she stiffens and doesn't shake
much, to start. By the time she is shuddering, we are almost always
already there. That doesn't mean we can't use the shuddering, because
it will help ensure closer to 100% that we notice the event. But I'd
like to catch things even earlier.

One of the reasons I'm thinking more towards the mute, is in fact
because my wife and I are so good, already, at detecting the early
gasp. One of us never leaves her, by much distance. We run around
turning things down, when she isn't using the devices. That is, when
we think of it. Which isn't something we are always conscious of,
since we've learned to tune out the sound and have to fight that
tendency. However, she would quickly get used to an auto-mute and
would learn to _accept_ it's rules and the effect would be that our
own failures to be constantly conscious and attentive to the equipment
would be covered better, leaving our own fine-tuned detection skills
to operate better as a practical matter.

I suspect this will be an ongoing process of adaptation for most of
the rest of our lives. Piecemeal technical solutions will address
only some of that. But even one partial-crutch is appreciated.

Jon

 

[Jon Kirwan]

Just a wild thought... Video surveillance with motion detection.

It's not a wild thought, at all! Been there, done that. We live the
problem and have tried that, so it's a great suggestion. (We have
baby monitors running all the time, too.)

We just cannot sit around glued to a screen. We must keep house, work
on outside projects (we live on a farm with chickens, guinea hens,
peafowl, and acres of gardens and orchards), clear out downed trees,
make wood boards and chop and stack wood, repair the driveway or
broken water pipes, etc. I'm building a new home for my son in one
corner, by hand without help except for his -- which was a very
serious problem when pouring concrete.)

Besides, motion by itself isn't 'detection' of an event. She moves
around freely, all the time.

And I think the video processing required to 'detect' an event from
the images would likely be beyond my skill set to imagine. I've done
spatial filtering optics and vector light propagation through optical
systems and beam-forming for underwater detection systems (with
propagation of sound across thermal layers), so I am comfortable with
mathematical techniques. I just lack the imaginative ideas needed to
see my way clear to something there. If someone else knows enough to
suggest some details, I might give it a heave or two. But I'd need to
'understand' it.

Thanks,
Jon

 

[Baron]

It's not a wild thought, at all!

Thankyou for not rejecting my suggestion.

Been there, done that. We live the
problem and have tried that, so it's a great suggestion. (We have
baby monitors running all the time, too.)

We just cannot sit around glued to a screen.

I wouldn't dream of suggesting that you spent your time in front of a
monitor screen.

We must keep house, work
on outside projects (we live on a farm with chickens, guinea hens,
peafowl, and acres of gardens and orchards), clear out downed trees,
make wood boards and chop and stack wood, repair the driveway or
broken water pipes, etc. I'm building a new home for my son in one
corner, by hand without help except for his -- which was a very
serious problem when pouring concrete.)

Besides, motion by itself isn't 'detection' of an event. She moves
around freely, all the time.

And I think the video processing required to 'detect' an event from
the images would likely be beyond my skill set to imagine. I've done
spatial filtering optics and vector light propagation through optical
systems and beam-forming for underwater detection systems (with
propagation of sound across thermal layers), so I am comfortable with
mathematical techniques. I just lack the imaginative ideas needed to
see my way clear to something there. If someone else knows enough to
suggest some details, I might give it a heave or two. But I'd need to
'understand' it.

Thanks,
Jon

There are systems which are capable of detecting changes in an image and
following those changes around. Normally you would be looking for
movement there. If instead you looked for lack of movement, that could
trigger an alarm. I know that PIR detectors can detect the heat from a
body continuously. So a IR camera might do the job.

 

[ehsjr]

To start off, I'm not looking for a specific design, though of course
I will be very happy for any such attempts. I'd like some thoughts
about approaches or problems I may need to consider. I'd be happy to
then expose some design I come up with, to criticism.

I need an auto-mute circuit that I can use to retrofit devices that
provide an amplified audio output to a speaker or speaker pair. These
include television sets which use UP/DOWN buttons to set volume all
the way to resistor-based knobs and wheels that set volume.

I could consider not "getting everything" and instead just focusing
only on those devices which use a resistor to control the volume,
interceding at that point (using the existing control but adding a
circuit around it.) In that case, the circuit would need to behave
the same regardless of which resistive 'end' was used to set the
highest volume. I'd like to handle TV sets that use UP/DOWN buttons,
too. But even _some_ solutions are better than none.

By 'retrofit' I mean that I cannot add new control systems to existing
ones by drilling holes and making the operation more complex to handle
-- the operation must be fully automatic and set by me _before_ I open
up the units and insert the circuit, without having to create any
external access holes or buttons, etc.

My daughter has grand mal seizures that my wife and I need to hear the
beginnings of. My daughter loves to turn on stereo systems and music
boxes, quite loud at times. She enjoys listening and often has her
computer software playing something loud while having a CD player
playing something else in the same room, while still something else is
playing on a CD player in the next room, as well. We don't want to
take that away from her, but it also makes for a noisy environment
which can easily mask our ability to detect a seizure as early as we'd
like to. The results of our missing the early sounds of a seizure
event could potentially lead to broken arms, or even death in an
extreme case. So this can have very important consequences.

We've used timers on the power plugs. But besides the fact that she
moves things around from place to place if it "doesn't work" from her
point of view, using a timer greatly complicates our own life. She
needs to have the ability to initiate the operation by using controls
that already exist on the device. (She is 25 years old, but operates
much like a 4 year old. She can learn some things, like how to turn
the volume control knob, but using timer boxes greatly complicates
operation and thus greatly complicates both her and our lives.)

What I need is something that doesn't increase the complexity of her
use of the device. She simply needs to learn to "adjust the volume"
as she always does to cause the mute operation to cease, instantly.
But that action should initiate the start of a new timing cycle. The
auto-mute effect needs to take place after about 10 minutes of use,
but I'd like to be able to set that range from perhaps 1 minute to 15
minutes. That said, to be completely honest about it, I could live
with a fixed 10-minute delay.

The power source is an issue. These devices I'd modify _do_, of
course, have internal power supplies and I could scarf around to find
something to attach to, of course. How the ground will relate to the
speakers, I don't know. It may depend on the device. The speaker
outputs may even be galvanically isolated. Best would be that energy
is derived from the sound system's own delivered power to the
speakers, so that it's 'universal' in that regard. This would save me
from replacing batteries or having to make custom designs for each and
every situation's internal supply modifications. (While the voltage
is building up in such a case, though, I'd like the unpowered circuit
situation to be 'unmuted.') But battery powered, if necessary, is
acceptable if I don't have to replace them more often than once every
few months and so long as I'm able to fit the battery system inside
(in some cases, that will be 'hard'.)

What would work best for her is that if she 'fiddles' with the volume
control, the mute operation ceases and the timer starts.

This needs to work on CD and karaoke players, stereo and mono
amplifiers, TVs, etc. Almost all are wall-plug powered. Not all,
though. Some use multiple D-cells ('boom boxes') or allow an
'either-or' operation, using batteries if unplugged from the wall.

I've only just begun to think about this and my own limitations in
experience are suddenly in evidence to me. My first thought would
only work on the resistive type controls, would use a micro to monitor
the value (ADC) and then control a digital POT I select. It would
need power but I could use an MSP430 to mitigate that problem, using a
small CR2025 or CR2032 which would last quite a while. (The timing
requirement of minutes, alone, almost forces me to think in terms of a
micro, though I can think of a few analog circuits using a cap and
mosfet that would handle such times.) I would probably need custom
programming, a tweak for the input gain perhaps, and perhaps a
different digital POT for each unit I modified. But at least I can
see how to handle that.

Thoughts and criticisms meant constructively are appreciated.

Jon

Let me see if I understand the functional requirements:
1) Every X minutes, mute the device
2) Un-mute it when the volume control is fiddled

Is that exactly what you want in terms of function,
ignoring the technical requirements (no holes, power
supply considerations, the muting device or circuit
needs to work with several different pieces of equipment,
whatever)?

Ed

 

[Jon Kirwan]

Thankyou for not rejecting my suggestion.


I wouldn't dream of suggesting that you spent your time in front of a
monitor screen.


There are systems which are capable of detecting changes in an image and
following those changes around. Normally you would be looking for
movement there. If instead you looked for lack of movement, that could
trigger an alarm. I know that PIR detectors can detect the heat from a
body continuously. So a IR camera might do the job.

(And I seem to recall some short discussion here about a new kind of
sensor along those lines which inherently sets up potential
differences when there are changes in the flux across the surface.)

Detection remains a problem here. Often, she lies down and doesn't
move -- either awake or asleep. Too many false positives and we'd
learn to ignore it.

Jon

 

[Jon Kirwan]

Let me see if I understand the functional requirements:
1) Every X minutes, mute the device
2) Un-mute it when the volume control is fiddled

Is that exactly what you want in terms of function,
ignoring the technical requirements (no holes, power
supply considerations, the muting device or circuit
needs to work with several different pieces of equipment,
whatever)?

Yes. That pretty much nails what I'd like to try out, right now.

As should be abundantly clear, we are hacking out new territory and
always experimenting to improve the quality of our results with her.
So once we field something, we may discover new effects to worry
about.

It's kind of like the "theory of pendulums." You can start out very
neatly describing the motion, constraining the swing such that sin
theta = theta to a reasonable approximation to eliminate confounding
terms, and yield the well known pendulum law. However, when you start
actually _building_ pendulums and when you improve your measurement
precision of the timing over time, you find the theory doesn't take
into account the diameter of the holes that rock on the pins you
build, relative to each other, which can affect the predictions by 2
or 3 percent or more -- which cannot be explained by timing
measurement errors alone. So you search out this new effect, discover
it, and then want to deal with it, too.

I expect that once we get this working, what is currently obfuscated
by the magnitude of the current problem will be stripped away to view
and we'll probably have some new thoughts to add, then. For now, I
can't see any of that so this is exactly what I'm looking for.

It goes in incremental steps. Like life.

Jon

 

[Jon Kirwan]

An automatic volume-reducer can be relatively easy.

If TV and stereo are relatively modern, they will have remote
controls
for volume, so it's just a matter of periodically sending the
incremental-down signal (different signals for all the devices,
of course) at a prescribed rate, so that after X minutes, the
volume is down by N steps...

This is an answer towards a different part of the piecemeal problem.
And yes, if I could lock down a remote control device I build so that
it points at the TV set supporting it, that could work.

However, I do still have some of the old vacuum tube TVs and it is a
Bell and Howell that she uses, right now. No remote control, IR or
otherwise. But it does use up/down buttons and not a rotating knob.
(Yes, I have yet another one that does use the old rotating tuner and
volume control! Some of these old babies just keep on going!)

LIRC open-source project has emitter plans and software; it
can't be too hard to implement.
Agreed.

Not sure about iPod and computer sound, but Mac remote
controls exist (Bluetooth, I suspect) that could be reverse-engineered
with some confidence.

No Mac here (mostly because I just have a hard time paying that much
-- I worked on the original Lisa computer [monochrome and $10k each]
and loved it and do like Macs for what they offer... just price, you
know?) No bluetooth here in the home, anywhere. And I use a basic
cell phone that doesn't support it. (I don't think I ever will start
using bluetooth unless it gets rammed down my throat and when I buy
gps systems I get ones that don't use bluetooth, just so you know.)

The speaker system on her computer can be modified. Or I could simply
design and build one from scratch. The amplifiers are only a few
watts and I know how to design something cheesy but workable by
myself! So I've been thinking I might do that in this case.

In any case, the normal knobs or the remote unit will turn the
sound back up without fuss.

I'm trying to reduce maintenence issues (battery replacement that is
too frequent, for example), additional burdens upon our own need to
remain aware and conscious that may hinder our other work, and
mounting and fixtures which themselves may complicate our lives or
further endanger her because they simply exist (unless carefully
designed, a mounted controller, for example, could actually present
something she lands on during a seizure.)

The focus on placing whatever the solution may be _inside_ the unit
avoids the introduction of something new to the ambient environment
equation. Which is why I'm looking that direction, right now.

Lots of good thoughts from everyone and I appreciate it.

Jon

 

[Jon Kirwan]

This is an answer towards a different part of the piecemeal problem.
And yes, if I could lock down a remote control device I build so that
it points at the TV set supporting it, that could work.

Well, kind of. I spoke too soon. She doesn't _use_ a remote control.
She will go to the TV, itself. So assuming all the rest, the IR
controller (for example) would need to have some way of knowing she
did that.

Jon

 

[Jon Kirwan]

<snip>
Now I am just thinking aloud... could be some direction to look,
the vibration sensor or 'angle' (vertical versus horizontal, and speed of position
change) could be one of those 3 axis acceleration sensors, some people here (not me)
have extensive experience with those.

So many possible sources of data (sound, vibration, video pixels, and
now accelerometer data), so much needed research to analyze a usable
way to process all that for my circumstances. I love it. I suppose I
could bury myself in this for years and years.

Accelerometers require power and in this case to be usable would need
to be attached to her (non-trivial) and powered continuously. I
couldn't sample them, periodically, because I'd need to know "right
away" and sampling couldn't occur once a minute or once every 10
seconds. It would have to be relatively continuous and this places a
burden on the power source. Besides the difficulty of keeping it on
her, somehow, without her clawing it off. And did I mention RF? More
power, though that could be used only upon "detection."

False positives are okay. Up to a point. She is very active, skips
and dances a lot and loves to jump up and down while clapping her
hands together, laughing and giggling loudly. She is very happy, by
and large. I'm not sure how to hew very close to zero false negatives
while keeping false positives to a "dull roar" here. Something may
come to mind, so I'll keep this in view. But right now I'm not sure
how to deal with continuous sampling, power, keeping such a thing
attached to her, together with usable detection negative/positive
rates -- algorithms. Good ideas there may help push me along that
line, though.

Jon

 

[Jon Kirwan]

Accelerometers takes 1 to 2mA continuously, plus another 1mA for a
microcontroller. Yes, RF would push it up to 50mA area in burst, upon
detection. So, 200mAHr CR2032 coin cell should last 100+ hours.

100 hours per change would get old, fast. Call it 8-10 per month?
okay. If it really saves her just once...

Still have to figure out what to process and how.

However, you have to build something fun for her to wear it. Musical
watch?

I think Vladimir (I love practicing the proper Russian pronunciation
of that name!) pointed out an excellent option (which I've purchased,
but haven't seen yet) that the TI MSP430 is inside of -- it's a watch
that includes 3-axis accelerometer (if I remember what I read
correctly) and RF capability and I already have all the needed
development tools and know how to use them.

It's possible it will work out.

Jon

 

[Jon Kirwan]

Would it do to have a camera mounted fairly low, so that continuous motion
only in the lower half of the image corresponds to a siezure? This also
assumes she isn't constantly moving around when lying down, of course the
magnitude of motion could be controlled too.

Interesting questions. Some hours of each day, she just goes into her
room and lays down under a blanket and looks at the ceiling, laughs a
bit, rolls over, etc. Assume there is a camera mounted there. If she
has a seizure during her sleep (very rare, as it is almost always
within about 1.5 to 2 hours within waking up), that might work. But
she plays, too. Besides, her seizing when under a blanket is not the
kind of "wild flapping" that you see on TV, sometimes. It's as though
all of her muscles are tightened up -- she feels like a solid rock --
and she is shaking somewhat. There is NO oxygen getting into her
blood, so she damages her brain if it lasts too long. It is very
tense, low-motion, and she can grind (destroy, even) her teeth in the
process or cut her tongue in half if her jaw clenches down hard
instead of up. Sometimes, the jaw opens and closes. Sometimes, it is
stuck open or stuck closed. Sometimes, that changes during the
seizure. But by and large, not a lot of motion. Just a sudden high
tightness tensing of muscles and fairly low-intensity motions that
last for between one minute and as much as four.

Which reminds me... a pulse-ox might be appropriate for detection
after the fact. Oxygenation levels should drop precipitously. And
these are dirt cheap, nowadays, and not hard to develop either. Of
course, it doesn't solve the detection problem until after it is way
too late. But it would make sure we know close to 100% of the time
when one happens. And that has value, too.

We do have, sometimes, some indications 10 or 20 minutes early. A
kind of spasmatic jerk in her hands and shoulders that isn't visibly
noticeable, but if you are holding her you can feel them. They are an
indication that we are within an hour or so and that can allow is to
dose her before it happens or to at least hover and be there at the
right time.

My instincts tell me to hold off of using video processing, for now.
Difficult and expensive for all the needed coverage areas, processing
complexities, etc. I need to explore other solutions that I can 'see'
the other end of more readily, first.

I'd also still like to try out an auto-mute or two, as well. Those
aren't more direct detection, but they enable our own ears and that's
also important. The twin approaches... auto-mute and direct detection
on her body are like playing this from two ends to the middle. On one
end, there is our own fine-tuned detection (ears and brain) where the
auto-mute helps us; and on the other end there is the direct detection
that provides an entirely different pathway for detection and can be
made to reach us by altering the 'signal' so that we definitely notice
it.

Jon

 

[Jon Kirwan]

I'm thinking more of a central point in the house that generates a
steady stream of 'volume-slightly-down' commands, and using
wiring (like, the black/yellow pair on telephone connectors) to
run to each room, and blast out the codes in all directions.

The central controller eventually turns the volume all the way down,
but not by a single 'mute' step. And, it has its own IR emitters, there's
no interaction with any handheld remote control option.

Egads. I think I'm not quite ready for all that, just yet. And even
then, it's only a partial solution as it only handles those cases
where IR emitters are useful. I may get there someday?

Hopefully, the seizures will just stop or else we will outfit her with
a medical device to halt them. (There are two such things available
as I speak, which may or may not yield results for us when and if we
decide to try them. One is a vagal nerve stimulator and another is
actually placed into the brain, itself.)

Short of that kind of cessation or cessation because of death, the
right solution is surrounding her by a knowledgeable human community,
good record keeping, and appropriate physical, technical and chemical
adjustments. The balance in all that is a path one walks and not a
destination one can ever hope to ultimately reach.

Jon