retrofitting an auto-mute volume control?
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From: Jon Kirwan on 12 Dec 2009 17:00 On Sat, 12 Dec 2009 21:42:28 +0000, Baron <baron.nospam(a)linuxmaniac.nospam.net> wrote: >Jon Kirwan wrote: > >> On Sat, 12 Dec 2009 20:57:23 +0000, Baron >> <baron.nospam(a)linuxmaniac.nospam.net> wrote: >> >>>Jon Kirwan wrote: >>> >>>> On Sat, 12 Dec 2009 12:45:55 GMT, Jan Panteltje >>>> <pNaonStpealmtje(a)yahoo.com> wrote: >>>> >>>>>On a sunny day (Fri, 11 Dec 2009 17:33:16 -0800) it happened Jon >>>>>Kirwan <jonk(a)infinitefactors.org> wrote in >>>>><q8n5i5d8ln8frinntf0p5ta7me4p22srk2(a)4ax.com>: >>>>> >>>>>>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. >>>>> >>>>>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 >>> >>>Just a wild thought... Video surveillance with motion detection. >> >> 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. (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
From: Jon Kirwan on 12 Dec 2009 17:08 On Sat, 12 Dec 2009 16:46:21 -0500, ehsjr <ehsjr(a)nospamverizon.net> wrote: >Jon Kirwan wrote: >> 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)? 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
From: Jan Panteltje on 12 Dec 2009 17:39 On a sunny day (Sat, 12 Dec 2009 12:48:42 -0800) it happened Jon Kirwan <jonk(a)infinitefactors.org> wrote in <3cv7i5l8174ocq72bdrg3osdpovjdqeblj(a)4ax.com>: >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. There are other possibilities. I assume you have considered CCTV, a camera and monitors. A camera gives a new possibility, in this digital age, I think one can do some analysis of the picture, for example 'falling over' could be detected perhaps, with some frame by frame processing. Never programmed that, but I did do motion detection, and for sure frequency of motion can be detected. It is said that Microsoft is coming out soon with a new version of the Xbox or one of it's variants (dunno), that has a camera that can detect gestures... There must be some game developer API available... 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.
From: whit3rd on 12 Dec 2009 18:10 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... LIRC open-source project has emitter plans and software; it can't be too hard to implement. Not sure about iPod and computer sound, but Mac remote controls exist (Bluetooth, I suspect) that could be reverse-engineered with some confidence. In any case, the normal knobs or the remote unit will turn the sound back up without fuss.
From: linnix on 12 Dec 2009 18:14
On Dec 12, 2:39 pm, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > On a sunny day (Sat, 12 Dec 2009 12:48:42 -0800) it happened Jon Kirwan > <j...(a)infinitefactors.org> wrote in > <3cv7i5l8174ocq72bdrg3osdpovjdqe...(a)4ax.com>: > > >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. > > There are other possibilities. > I assume you have considered CCTV, a camera and monitors. > A camera gives a new possibility, in this digital age, > I think one can do some analysis of the picture, for example > 'falling over' could be detected perhaps, with some frame by frame processing. > Never programmed that, but I did do motion detection, and for sure frequency of > motion can be detected. > It is said that Microsoft is coming out soon with a new version of the Xbox > or one of it's variants (dunno), that has a camera that can detect gestures... > There must be some game developer API available... > 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. Yes, even 1D accelerometer would be enough to detect impact (falling). But perhaps she is just jumping around for fun. So, accelerometer could be part of the sensor, but not only one. However, false positive might not be so bad, the OP might want to know when she is having fun anyway. |