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How Can I Build a Portable "Dead-Man's" Switch? 169

An anonymous reader asks: "I'm a widower caring for my very disabled child. I have family who check in on me often, but not reliably, and not every day. How can I rig up a 'dead-man's switch' that will alert family or emergency services should something happen to me, so that my child can be cared for? Her medical needs are significant enough that being alone for even an hour could be fatal for her. We do occasionally get out of the house, so a GPS type cellphone and a heart-rate monitor watch would seem to be the ticket, but how to link the two and get the desired dialing behaviour?"
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How Can I Build a Portable "Dead-Man's" Switch?

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  • Alive Heart Monitor (Score:5, Informative)

    by Anonymous Coward on Sunday September 24, 2006 @05:27PM (#16178083)
    There's this bluetooth enabled Alive Heart Monitor [] that apparently works with GPS, and with a PDA/smartphone or a server. You'd probably need to write (or hire someone to write) an application to use the data for the actual contacting other people in case of x part, but the hardware seems to exist for what you want to do.

    Have you considered a medic alert bracelet for the times when you're out? Or are you in remote, non-populated areas?
    • Finally!! The perfect weapon to stop mass zombification getting out of control.
    • Re: (Score:2, Insightful)

      by theLOUDroom ( 556455 )
      There's this bluetooth enabled Alive Heart Monitor

      Great! Everytime he walks by a WAP or microwave, emergency services will get a call saying he's dying.

      Perhaps a more robust communication method might be warranted here?
      • by arivanov ( 12034 )
        If I understand the gp post correctly, the monitor talks to a server, not to the emergency services directly. So all the server needs to do is behave like every well behaved monitoring application should by using a set of alarm thresholds:
        • Alert only after X positives or Y minutes of positive alarm
        • Alert only after the server has failed to poll the client for X consequtive times over Y minutes
        • Turn alert off after X negatives or Y minutes of negative
        • Clear positive counters after X negatives or Y minutes o
    • by flumps ( 240328 )
      .. but what if you're not dead, just very very badly hurt or in a coma or something?
  • try shopping (Score:4, Informative)

    by pizpot ( 622748 ) on Sunday September 24, 2006 @05:28PM (#16178087)
    May I suggest you visit a medical store? Get a device like those made for hospitals or old folks. Probably easier than posting to slashdot.
    • Re: (Score:1, Flamebait)

      by tlh1005 ( 541240 )
      This is informative?? Some people just have a need to be rude. Of course one could visit a medical store but it's obvious the inquirer is looking for better ideas or opinions. Should we now just respond to all desktop related questions with, "Go visit Best Buy"...... They sell a lot of software, computers, and electronics, they'll know best correct?
      • by XoXus ( 12014 )
        It's not at all "obvious the inquirer is looking for better ideas or opinions", since they don't mention that they've exhausted (or even examined) medical store offerings.
        • by Jaruzel ( 804522 )
          C'mon, they've made the effort to post to slashdot*, it's assumed they've exhaused all other avenues.


          *Because we all know how easy it is to get a submission accepted. ;)

      • Re:try shopping (Score:5, Insightful)

        by honkycat ( 249849 ) on Monday September 25, 2006 @12:01AM (#16180935) Homepage Journal
        Based on the information we're given, I think the only compassionate answer is "don't do this yourself." If a person's life depends on the reliability of this solution, trying to come up with a clever hack is just plain irresponsible. In that case, you really need to buy a tested off-the-shelf solution.
        • Re:try shopping? (Score:5, Informative)

          by JumpingBull ( 551722 ) on Monday September 25, 2006 @05:37AM (#16182737)

          Friends, lots of them.
          If you have this load as a caregiver, just having people around, helping and having someone to kvetch with is not just a good idea, but critical, if only for your own emotional health.
          There are other people in the same boat, so perhaps finding or forming a community might be the way to go. Something less collective then a commune, but a structure like [] (if christian). Equivalent communities exist in other religious traditions, as well as the religious (monks, nuns and others)associated with a belief structure.

          Technolocial measures sound neat, but they have so many points of failure compounded by the people that have to be around to insure that they don't fail, that I would be suspicious of the lot. Not that I feel that way, but I would adopt that attitude by policy.

          Consider the call clearing center that an alarm panel calls into: the UL standard calls for redundant systems that fail safe, two levels of backup power generation, duplicated sites, alarm receivers that fail busy so calls can get through, requirement for manual control, full data logging, crisis triage, etc.

          A full technology solution is suspect, a hybrid system is probably better, and you have the adventure of searching out the real players from the fakes. Look to the service providers that a hospital might use.
          And look carefully at response time: under disaster conditions it probably will swing out past your hour requirement.

          Oh, you have to concern yourself with the other side: Are your critical systems on backup power? UPS and autostart generators? Tested each week?
          There is a very good reason why the backup batteries in the telcos are usually glass lined lead-acid submarine batteries that (usually) power diesel boats. I don't think the cable co's are quite there yet. Just a guess.

          Feel free to email me if required - there are a lot of details I don't know, and a phone call might be needed.
          Don't be afraid of the complexity, a few minutes with some brainstorming buddies can cut that down to size. The legwork is a different story!
          Best of luck!

      • The obvious question is 'why the hell are you asking slashdot?' We're just a bunch of guys (mostly) who like computers and gadgets. Do you think even 2% of the people responding will be at all qualified? (never mind what the spread is for other ask slashdots).
    • Re: (Score:3, Informative)

      by ozmanjusri ( 601766 )
      Shopping's a good idea, but a better product would be one of the Automated Lone Worker Protection systems ( or perhaps one of the firefighter/rescuer's Man Down alert tools.
  • by SirLoadALot ( 991302 ) on Sunday September 24, 2006 @05:34PM (#16178133)
    If we are talking about a serious system here, you aren't going to be able to do this yourself. Just for starters, think about how complicated this would be if you decide to have a shower. You will have to deactivate the whole shooting match and then get it all back up and running again afterwards. Of course, if you slip in the shower, you're screwed. There are already solutions out there that you can sign up for. One that I have seen is a pendant you wear around your neck that has a button on it. One push, and your relatives are notified by phone. Or, fail to push the button on a regular basis and a phone call comes from the monitoring service, who can also dispatch 911, etc. Finally, at the risk of being harsh, if you truly believe you may die suddenly with no notice at any time, you seriously need to reconsider your current care arrangements. You do not strike me as qualifying to care for some with the needs you imply in your question. Please take this as honest advice, not a flame.
    • by dr_dank ( 472072 ) on Sunday September 24, 2006 @09:08PM (#16179665) Homepage Journal
      You do not strike me as qualifying to care for some with the needs you imply in your question. Please take this as honest advice, not a flame.

      As hard as this might be for submitter to admit, I have to agree. Around the clock care, be it in the home from a nursing service or in a residential facility can be expensive, but there may be a sliding scale available via some organizations according to need. Chances are that there is an organization that caters to the submitters daughter's specific condition or circumstance.

      This is too important to trust to a Rube Goldberg contraption that one of us dingbats on Slashdot recommended.
    • One push, and your relatives are notified by phone. Or, fail to push the button on a regular basis and a phone call comes from the monitoring service, who can also dispatch 911, etc.

      I was originally thinking along those lines too - sort of the benevolent version of the 118 minute clock in Lost, or the Prozium wristwatches in Equilibrium. But then I remembered that you'd have the same problem as in Lost - never being able to get a full night's sleep. If the delay is longer than 7-8 hours, that's well outside
    • by Kanasta ( 70274 )
      Indeed. If an hour could be fatal, maybe being notified won't help if they take 2hrs to get there, and maybe she should be living in a hospital.
  • by Bones3D_mac ( 324952 ) on Sunday September 24, 2006 @05:39PM (#16178177)
    Being disabled and prone to dangerous falls myself, I know this sentiment all to well. Needless to say, I've had difficulty finding something that would not only work within my home, but anywhere I go, without needing to carry a full-blown cell-phone.

    Something like a human-based form of OnStar, but with a heart/lung monitor and an accelerometer/impact sensor (to detect the speed and severity of a fall).
    • Re: (Score:3, Insightful)

      by RevAaron ( 125240 )
      Carrying a full-blown cell phone is precisely what this bloke seems to expect- if you've found solutions that include that, perhaps you could share?

      Frankly, the poster's situation sounds serious enough that a $20/month cell phone bill is the least of his worries.
    • Re: (Score:3, Informative)

      by RevAaron ( 125240 )
      One other little note- OnStar uses a cell phone. One of the reasons you pay monthly to use it.
  • Professional (Score:4, Informative)

    by TLouden ( 677335 ) on Sunday September 24, 2006 @05:56PM (#16178319)
    My aunt uses a device which is medically implanted by her heart. If her heart stops is defibs and logs a report. The same device can be modified to make a phone call and pass along GPS coordinates. Problem is, this requires surgery so it is not a DIY project. It is a nice solution though and water proof too. Talk to your doctor.
    • by Anonymous Coward on Sunday September 24, 2006 @06:47PM (#16178665)
      Problem is, this requires surgery so it is not a DIY project

    • by Doctor Memory ( 6336 ) on Sunday September 24, 2006 @10:06PM (#16180109)
      If her heart stops is defibs and logs a report
      Wow, that'd be a freaky log file:

      [24-SEP-2006 16:44:52] Fibrilation detect
      [24-SEP-2006 16:44:56] Fuxx0r3d
      [24-SEP-2006 16:44:56] Defibrilation start
      [24-SEP-2006 16:44:56] Defibrilation complete
      [24-SEP-2006 16:45:01] SYSTEM RESTARTED AT 16:45:01 ON 24-SEP-2006

    • Re: (Score:2, Funny)

      by camperdave ( 969942 )
      "Don't worry, you won't get sick. I could cut open your chest and sow a dead Cat inside and you wouldn't get an infection. Not with the ammount of antibiotics I'll be shooting into you."
  • by sakusha ( 441986 ) on Sunday September 24, 2006 @06:19PM (#16178475)
    I saw an interesting article in a Japanese newspaper, it relies upon a relatively unique cultural circumstance, but I think you'll be inspired to think of how it can be adapted. The device was invented for one guy's family, but after it got some writeups in the newspapers, the idea was so popular that it went into production, and now lots of people have them.

    There are many elderly Japanese people who live alone, some are deaf and can't use the phone, etc. so it's hard to get a way to check in on them to see if they're still alive. But almost every home has a hot-pot, an insulated pot with an electric heater used to keep water near the boiling point, to make tea every day. So some clever guy put a sensor in the hot-pot, if nobody picks it up within a day, it phones a preprogrammed number to alert someone to check in on them. Yeah, these people drink a lot of tea, it was the only thing they could think of that elderly people did EVERY day.

    Of course this only checks in once a day, but you could probably think of other ways to adapt this idea.
    • Re: (Score:3, Funny)

      by east coast ( 590680 )
      I'm a beer drinker you insensitive clod!
    • Re: (Score:3, Insightful)

      Hmm, you could look at the water meter, and if they haven't used any water in a day, as long as they don't have any automatic waterering devices or leaking toilets, it would tell them that there was a problem. The automatic devices and leaks could probably be detected and compensated for with fuzzy logic. Apartments without water meters would have to have one installed, not a real big problem.
      • Re: (Score:3, Informative)

        by ForestGrump ( 644805 )
        Actually it's already in use, but instead of putting the trigger on a hot water pot, it's put on the refrigerator in reitrement castles.

        The idea is that when you get up in the morning, you'll go to the fridge for food. If nobody opens the fridge beyond a certain time, then an alert goes off so somoene checks on the resident.
        • by xtracto ( 837672 )
          That reminds me of a joke... it may not be the same in english (I heard it originally in spanish):

          Why does married men get fat?

          Because when you are single you get into your home, open the fridge and think "the same thing again" (pizza, hamburger, chinnese food, etc) and get to your bed.

          And, when you are married, you get to your home go to your room "open" the bed sheets and think "the same thing again" and go to your fridge.

      • by J'raxis ( 248192 )
        Instead of the water meter, put the monitoring device closer to something you know wouldn't be automatically activated: a faucet, shower head, or something similar.
    • Re: (Score:3, Insightful)

      by Trogre ( 513942 )
      Dead-mans switch on the toilet flusher? Surely most elderly people would use this every day (and night).

  • Ya see... (Score:4, Funny)

    by CODiNE ( 27417 ) on Sunday September 24, 2006 @06:24PM (#16178519) Homepage
    My usual "dead man's switch" is a live grenade... however it probably wouldn't fit your situation very well. Nevermind. Good for hostage situations and job interviews though.
    • Re: (Score:2, Funny)

      by CODiNE ( 27417 )
      I forgot to mention blind dates... good for those too.
      • by CODiNE ( 27417 )
        Oh wait, this is Slashdot, forget about the dating stuff.
        • by elrous0 ( 869638 ) *
          In the spirit of something more appropriate for the /. crowd, I should point out that this is also a great way to intimidate Hutts into giving you more money for your bounties.


  • by Sam Nitzberg ( 242911 ) on Sunday September 24, 2006 @06:36PM (#16178599)
    This is not everything, but this type of phone might help-
    It is normally meant for kids, but it has reduced number of buttons, and a dedicated emergency button... r?item=phoneFirst&action=viewPhoneDetail&selectedP honeId=2060 []
    from the site-
    Migo from Verizon Wireless is a kid-friendly wireless phone that lets parents and kids stay in touch. It's fun for them, and added peace of mind for you. The Migo phone has a simplified keypad that allows you to program in 4 numbers, an incredible speakerphone and a dedicated emergency key. And with Chaperonesm, you can use your handset or PC to locate your child's Migo. This is the perfect phone to keep kids and parents connected.

    Note: I have no interests / investments / work relationship with verizon wireless.
  • Some ideas (Score:5, Interesting)

    by RobinH ( 124750 ) on Sunday September 24, 2006 @06:36PM (#16178601) Homepage
    I don't think you need a dead man switch. (I work with dead man's switches all the time in industrial robotics). What you could probably get away with is a vigilance control switch. From Wikipedia:

    Vigilance control, also called an alerter, is similar to a dead man's switch, the difference being that a vigilance control system requires that the operator press a button at specified regular intervals. If the operator fails to operate the vigilance control, a warning sounds, and should the driver still not operate the vigilance control the machinery will stop.

    I have one of these motorola pagers [] that my company gave me to carry around. It may only be available in Canada, but I'm sure you can find something similar in your area.

    At any rate, you can send a page to it with an email, and then you have the option to reply to the email with a canned response like "OK" or "Will call back soon", etc. I was thinking that you could write a script on a server that would kick off an email to your pager every 30 minutes and if it didn't see a response within 15 minutes, activate some kind of emergency routine like contacting a relative. The timing could be varied to your needs.

    It would be easier if you had something that hung around your neck, or a wristwatch that beeped every 15 minutes and required you to push a button to silence the alarm. Not silencing the alarm would somehow trigger your emergency routine. Using a windows mobile device or a blackberry (the API is available for free) you could write a program for one of these devices to do this task and send an email if you failed to respond.

    Of course, this only works during waking hours. I don't know if you hire someone to watch your child during the night while you're asleep or not.

    I ran across this article []. I wonder if it has gone any further than that.

    Good luck with the search.
  • by Henry V .009 ( 518000 ) on Sunday September 24, 2006 @06:36PM (#16178607) Journal
    Buy a cell phone. Call your relatives every hour on the hour to chat about your cats (you do have cats don't you?). They'll hate you for it. (Don't worry, they're family.) They'll stop answering the phone. They'll talk about the old lady going senile. But if you ever miss a call, they'll be there in a heartbeat to find out what's wrong.
    • Forget about all that techno-crap. Just tell your family you won $10M from the Lottery. They'll know the instant you stop breathing.
  • Your case seems too severe for this solution, and I DO NOT recommend you use it. Seek professional services and equipment.

    You could create a dead-man's switch using a computer with a voice modem and a GPS enabled cell phone. First, determine the longest amount of time the child could survive on her own. For my example I will use 18 hours.

    On the computer, you set a 12 hour countdown. At any time, you can reset the countdown. If you are going to jump in the shower, just reset it. Whenever the coun
  • On eBay, I recently noticed a cellphone designed for kids' use,
    known (in Australia, at least) as an "i-Kids"

    K-Mart had the pink version on sale (but each store had only ONE
    to sell, when we tried to buy one, so we missed out) for Au$ 35.

    See this (or similar) Aussie eBay item listing (of, better, the
    web site referred to in it) for details: with-GPS_W0QQitemZ270032251531 []

    In Oz, the thing comes locked to Vodaphone and might not work
    with other carriers' (except as
  • Just page people every couple of hours, If they dont get a page, they know something is wrong and can track you down via your GPS phone.

    Might not be perfect, but better then what you are doing now.

    ( im sure other professional 'life alert' sort of things are out there with 24/7 monitoring, but doubt insurance would pay for it )
  • At last, a lead in the Brian Wells [] case!

    It was you!
  • by frovingslosh ( 582462 ) on Sunday September 24, 2006 @07:26PM (#16178973)
    What you may want may not be a portable dead man's switch, and certainly not one that you need to die to triger. What might be a big help to you (and many other people) is software running on your computer that alerts people and does other things if you fail to check in on a regular basis.

    There is already one program that I know of that attempts to do this. It is called DMS, but I can not recommend it, it is very flawed. Among the issues I have with the program: It gives no warning before sending out the death notices that you program, no chance for the user to abort it. It will send out the notices and take other actions (such as deleting files) even if the computer has been down for a long time and then is rebooted (assuming that dms is in the start-up directory where it should be), such as caused by hardware failure or even extended power failure. And it needs manual attention to restart it's count down times, it doesn't recognize from keyboard or mouse activity that you are still alive and restart the countdown, so if you ever forget to reset the counter the messages go out with no warning and no chance to stop them.

    While the program is flawed, the concept is not. I keep hoping that I will find another version that addresses these problems and can be used for this purpose. I can see that this would be a big help to anyone concerned about the elderly living alone, anyone with a dependent child (or even a pet) who shares your concerns, and many other people.

  • Doctor. (Score:5, Insightful)

    by daeg ( 828071 ) on Sunday September 24, 2006 @07:42PM (#16179065)
    Talk to your doctor. You do not want a DIY solution when someone's life depends on it.

    You may also want to look into a managed care facility. You may be able to get them to accept both you and your child so you could continue to care for the child.
  • It's very likely that something will render you unconscious or otherwise impair your ability to call for help without killing you. A regular dead man's switch will not help in those cases.

    What might work is something that requires you to push a button at regular intervals during daylight hours to verify that you're still alive and well.

    The alternative might be to find someone to help care for your child. Easier said than done, I suppose.

    If you're feeling like you could die at any moment, maybe you should ad
  • One has to ask... (Score:5, Insightful)

    by csoto ( 220540 ) on Sunday September 24, 2006 @09:21PM (#16179739)
    if the dibility is such that life is at risk after one hour, why isn't the child in a care facility where they receive more than one person's care? Sometimes you think you're doing what's best for your children, but you're not.
    • Re: (Score:3, Insightful)

      by Thumper_SVX ( 239525 )
      I'd mod you up for this (I have mod points), but I want to post on this and say that a close friend of mine went through the exact same thing when his wife passed away earlier this year. His severely disabled child needed almost constant care, and despite the pain it caused him when I said it to him (and the pain it caused when he did it), he checked his child into a managed care facility. He knew that without his wife's help, he wouldn't be able to effectively work for a living. Without working, the qualit
  • by Schraegstrichpunkt ( 931443 ) on Sunday September 24, 2006 @09:30PM (#16179813) Homepage

    ... if her medical needs weren't "significant enough that being alone for even an hour could be fatal for her." An hour is just too small of a window to accomplish anything useful without having so many false alarms that your family won't take the alerts seriously anymore. You really need to re-evaluate your living conditions.

  • by vadim_t ( 324782 ) on Sunday September 24, 2006 @09:31PM (#16179819) Homepage
    This seems to be a strange way to approach the problem. Your worry is that your child won't be able to live for long if you can't provide the proper care for her. Then, wouldn't it be better to give her a way of asking for care to be provided?

    Assuming she's old enough, and not severely mentally disabled, this would seem to be the better option. After all, you could be perfectly alive and still be in a situation where you can't get to her fast enough.
  • Why build a dead-man-switch for this? I can think of a lot of scenarios where he would still be alive but not able to care for his kid. And besides: am I to belive that this guy is not sleeping at all? How does he know that his kid is in trouble if he does? Come on - this is such a lame excuse to come up with a dead-man's-switch.

    If one really needs to make sure that one is ok in 30mins intervals it is way easier to build a system that requires the push of a button to reset a 30mins timer before calling th

    • am I to belive that this guy is not sleeping at all? How does he know that his kid is in trouble if he does?

      Disabled people sleep too, you know, and don't face as wide a range of risks while they are safely in bed. He probably has a portable heart/apnea monitor if that is a risk. Those emit a fire alarm style noise when breathing or heart rate falls outside certain preset limits. My daughter had one for the first few months after she came home from the hospital. We actually slept better with it than af

  • You don't want a dead-man switch. You want a watchdog: a device which will send a message if you fail to reset it by pressing a button at least once an hour.
    • You don't want a dead-man switch. You want a watchdog: a device which will send a message if you fail to reset it by pressing a button at least once an hour.

      Make that once every 108 minutes. And move to a hatch. A plane will probably eventually crash near you, and you'll have a few volunteers to help.

  • by Pitawg ( 85077 ) on Sunday September 24, 2006 @10:39PM (#16180359)
    I make heavy personal use of Asterisk PBX software. It allows my blacklisting unwanted calls. It also allows my own system of "follow-me" call forwarding to pass calls to my cell if the home extensions fail to answer.

    Scheduling a call with the cron daemon is pretty easy. A kind of wake up service is also fairly easy to setup. With a cordless phone for home use, this could call said extension at various times of the day. When you answer the call, you would have to press a number or something to confirm that you are fine. Failing to press the number, it could make second attempts in case there was just fumbling, like a followup call within a minute or two. Failing more than once, it could email people, send calls to people, play a recorded message for each call appropriate for the target of the "notification". With the use of a cell phone, it could even check on you when away from home since it could work like any automated phone call/customer service line. Besides having a phone ring to wake you up in the middle of the night, hampering your sleep, I do not know how much help it would be in the night time hours. The cordless phones out now could cover most of people's small yards as well. It can also be easy to "911" yourself carrying it around with you, and with a little more effort, when you call 911, it could make other calls automatcally for you. Think 911 with a custom menu for types of emergencies with phone and email notifications to work with.

    The mutltiple notice to people for multiple types of needs using multiple methods of communication could be of some help. Cell phone calls to my house, being identified as my cell phone via "caller id", I get prompted with a menu to allow me to cause things to happen, when any other call would ring the phones in the house. A cell phone speed dial could be setup to call home and cause functions to occur using said "menus" which are limited by what you can get a pc to execute. (email, phone call outbound recordings, serial cable control for some devices, IR controls of something near the computer with a TV universal remote function....)

    Some of these ideas could enable automated response testing, and easy one button emergency notification. The GPS portion could be handled by recorded messages from cell phone orginating "emergency button" to mention the cell phone number/carrier to emergency contacts for use in tracking. Not so automated in that respect, but seems to be a workable solution.

  • by stevef ( 5539 ) on Sunday September 24, 2006 @11:12PM (#16180613)
    How about setting up a computer that requires you to punch in a code and hit the "execute" button. You could have it set on a timer... say 108 minutes.
  • Don't do it alone. (Score:2, Insightful)

    by rtb61 ( 674572 )
    Some things just can't be done alone. Use the internet to find peope in your region who have similar problems and help them help you. Not only wil someone be looking in on you but they will no exactly what you are going through and know how to care for your child in an emergency. Ask for help and give some back, technology is not the solution for every human problem and is best applied when it works in conjunction with people.
  • Carry a card in your wallet that says "I am a carer. If anything happens to me, my disabled child will be alone and in need of assistance. Please take the following steps: ... "
  • Medical Intelligence VPS []

    I'm not sure it can be programmed to your requirements, but at least it has all the required components in one package: GPS, GSM, ECG
  • I fail to see the difficulty here...

    1) Give her an account on your NAT machine
    2) Add "export TMOUT=3540" to her .profile
    3) Write a .bash_logout script that contacts everyone necessary
    4) Log her in

    If she doesn't whack a key every 59 minutes, it will log her out, thus alerting everyone necessary via email, paging, fax, whatever you like.
  • "Help! I've fallen, and I can't get up!" []

    Seriously. It may be marketed to the senior citizen set, but this or a similar service is exactly what you're asking for.

  • Hacking a solution (Score:3, Interesting)

    by danlyke ( 149938 ) on Monday September 25, 2006 @10:10AM (#16184665) Homepage
    As others have noted, this is something crying out for a social solution, not a technological one, but I'll indulge the "build your own" technological fetish for a moment.

    Monitoring for falls uses off-the-shelf accelerometers. Another poster in this thread mentioned a BlueTooth enabled heart monitor, of which there appear to be several. The hard bit is notification.

    Take a look at the Telit GM682 for the cell phone portion of your control. You can get 'em in quantity one from Spark Fun, and probably other places. It's basically a cell phone with a serial port that takes AT style commands, and is great for mobile hacking applications. After that it's just a microcontroller or a Gumstix depending on where your power consumption, weight, and processing power curves meet.

    Given my experiences with cell phone coverage and reliability, I'd have your actual dead-man switch on your server somewhere, and have it trigger if it didn't get an "alive" signal from the device you carry every so often, because it sounds like you'd far rather trigger false positives than have a false negative.
  • Obviously she is in pretty bad shape if she could die if unaided for an hour. Is your desire to have a child so great that you do not care about her suffering or the fact that you are ruining your life as well? The prudent course of action would be to simply let nature take its course. Her suffering and yours will be over. You will have time in your life for a new child that will be able to fulfill all the natural reasons while you desire one so badly.
  • This is your daughters life you are talking about, you seriously want to DIY something together in case the worse happens....

    Spend some money and buy something that is proven todo the job from a professional company.
  • If being alone for an hour can be fatal, this kid needs to have a professional available 24/7. If you happened to be knocked unconscious due to a fall or was in a very deep sleep, she could have a medical emergency that you wouldn't be able to respond to in time.
  • I think the most obvious solution would be to have friends. Let your coworkers know too.

The primary function of the design engineer is to make things difficult for the fabricator and impossible for the serviceman.