retrofitting an auto-mute volume control?
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From: Nik Rim on 12 Dec 2009 01:09 "Jon Kirwan" <jonk(a)infinitefactors.org> wrote in message news: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. > > 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 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
From: Jon Kirwan on 12 Dec 2009 01:25 On Sat, 12 Dec 2009 14:09:42 +0800, "Nik Rim" <querty(a)kbd.com> wrote: > >"Jon Kirwan" <jonk(a)infinitefactors.org> wrote in message >news: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. >> >> 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 > >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
From: Jan Panteltje on 12 Dec 2009 07:45 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? 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. So I wonder if you could make her wear some gadget with a some vibration sensor that would send a wireless alarm, if needed with GPS position, to you or some help agency? That would be more rest for you, and more reliable. The trick IIRC was in the detection of the sequence. 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. Maybe wear it on the arm, or on a belt?
From: Mark Zenier on 12 Dec 2009 12:36 In article <q8n5i5d8ln8frinntf0p5ta7me4p22srk2(a)4ax.com>, Jon Kirwan <jonk(a)infinitefactors.org> wrote: > >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 mzenier(a)eskimo.com Googleproofaddress(account:mzenier provider:eskimo domain:com)
From: linnix on 12 Dec 2009 13:01
On Dec 12, 4:45 am, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > On a sunny day (Fri, 11 Dec 2009 17:33:16 -0800) it happened Jon Kirwan > <j...(a)infinitefactors.org> wrote in > <q8n5i5d8ln8frinntf0p5ta7me4p22s...(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. >> 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. By the time you hear the sounds, it might be too late to avoid broken arms. But at least to have early treatments. > > Are you not approaching this from the wrong perspective? > > 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. > > So I wonder if you could make her wear some gadget with a some vibration sensor that would send a wireless alarm, > if needed with GPS position, to you or some help agency? > That would be more rest for you, and more reliable. > The trick IIRC was in the detection of the sequence. > 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. > Maybe wear it on the arm, or on a belt? If you can get help with precision military GPS technology, you can perhaps detect unusual positions such as laying on the ground. |