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How Can I Build a Portable "Dead-Man's" Switch?
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?"
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?
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.
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.
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).
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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.
-Tim Louden
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Upon reading just the title, that actually *was* what passed through my head, followed by trying to come up with what could be a legitimate use for such a switch.
I'd consider this to be either a legitimate question, or a fake one well crafted. It occurs to me that a suicide bomber really wouldn't have the need for GPS anywhere in this system, as the location of someone who has just blown himself up is really rather apparent.
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.
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.
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This is not everything, but this type of phone might help-
e r?item=phoneFirst&action=viewPhoneDetail&selectedP honeId=2060
It is normally meant for kids, but it has reduced number of buttons, and a dedicated emergency button...
http://www.verizonwireless.com/b2c/store/controll
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.
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.
"I have never let my schooling interfere with my education." - Mark Twain
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.
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 countdown reaches zero, the computer would produce an audible alarm.
If the audible alarm is not acknowledged in something like 15 minutes, the computer sends a SMS or e-mail message to the cell phone. To acknowledge the message, just reply to the sender. That would reset the countdown.
If the message to the cell phone is not acknowledged in an hour, the computer can lookup the GPS information on-line, determine if the phone was moving, call friends, neighbors, family, or even 911. You can use the voice modem to convert text to speech to broadcast a message and even the GPS coordinates to whoever the computer called.
Note: If the computer is used to dial 911, make sure the emergency response center knows that you have automated a message and will be providing GPS information.
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.
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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.
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.
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... 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.
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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.
I know I'm responding to a troll, but this brings up a serious point. Millions of people are walking around (and reproducing) who by all rights of nature should be dead. Are we weakening ourselves as a species? I think so...
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.
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.
Friends, lots of them.
Seriously.
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 http://www.bruderhof.com/ (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!
This is progress?
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.