X-Message-Number: 5581 Date: Sat, 13 Jan 1996 23:11:11 -0500 (EST) From: Charles Platt <> Subject: emergency alerts (fwd) The following exchange occurred on a different mailing list but is relevant to all cryonicists and is therefore being crossposted to CryoNet. --CP ---------- Forwarded message ---------- Date: Sat, 13 Jan 1996 12:14:16 -0500 (EST) From: Charles Platt <> To: CryoCare Forum <> Cc: Charles Platt <> Subject: emergency alerts On Sat, 13 Jan 1996, Mike Darwin wrote: > GOOD LUCK!!!!! You think motion sensors have problems! Wow! try using a radio > transmitter. Do you have a cordless phone? Had any problems as you moved > around? Considered the power supply problem? A transmitter takes a lot of > juice. To be sure it is working properly it would have to send out test signals > periodically. This means power, this means batteries. Transmitters are not to > be confused with wrist-watch sized recievers like pager watches. They are > bigger and they need bigger batteries. Now, Mike, we each have our special areas of knowledge, and frankly, yours is not hardware. There are possible answers to all your rather scathing quibbles. For example: The pulse monitor would require a very small amount of power to detect heartbeats. The base station (there might need to be more than one in a large home) can send an interrogatory message to the monitor every minute or two. If the monitor is detecting a pulse, it responds with a very brief (milliseconds) return signal requiring very little power. If the monitor is NOT detecting a pulse, it responds with a different signal. If the base station is unable to make contact with the monitor, it tries repeatedly; if still no success, it sounds an audible alarm in the home where it is installed, to alert the user that the system isn't working. If the user doesn't respond, the base station dials for medical help. > Ever owned a pulse detecting watch? Ever seen it give false readings or fail to > read? These things are pretty reliable, but not reliable enough without a lot > of fine tuning. In the system I have outlined, the detector could send a third type of signal if it is currently unable to get a good reading from the patient. The base station could then sound a different kind of alarm, telling the user than the monitor has been misaligned or whatever. Bear in mind that we're not interested in how fast the pulse is beating, only whether it is beating at all. Surely it would be trivial to design a system to detect this with reasonable reliability. > All do-able. But not straightforward. I've seen several > people try to tackle this problem of transmitters and these were the problems: > > 1) Compliance: if it is bulky and not actively useful like a pager or cell phone > people will not wear it. If it requires electrodes or patches to be attached to > skin compliance goes to near zero in "healthy" (i.e., not dying) people. > Compliance was lousy in dying people too. I agree the device has to be unobtrusive, but I don't see why electrodes or patches would be necessary. See below. > 2) The proliferation of cordless phones, radio operated devices, pager > transmissions, computers and other sources of noise is a major problem to use of > a transmitter. Depends which frequently band you use. Regular cordless phones suck, but the high-frequency models (which cost twice as much) are better. In any case, in my outlined system the base station would make repeated attempts to establish contact with the monitor device before giving up and sounding an "out of touch" alarm. This would allow the user to move through brief "dead spots" in the transmitter coverage without being annoyed by alarm signals. > 3) Hospitals use a device called a radio Holter monitor which transmits EKG > continuously to a recorder and the nurses' station. It is necessary to put > antennae at 10 ft. intervals in the halls. You will have to have an antennae in > every room of the home. If you go outside, it will alarm. Big nuisance=lousy > compliance. You're describing a system which requires high bandwidth: a large continuous stream of data. Mine would require only a very brief interrogatory message every minute or so. > 4) The point of the system I describe is that it requires nothing more than use > of a conventional alarm system. When you come home you switch on, when you > leave, you switch off. A simple light switch like on-off device would work as > well as a keypad. It's simple and easy. The on/off problem is trivial; any system could have sensors at each door which would automatically register when the user arrives or leaves. > 5) Any transmitter will be likely be removed for showering, bathing and some > autoerotic activities. It will also be removed by some people who defecate > before showering. These are very high risk times; falling in the tub is a common > way to die. Passing stool is also a high risk activity (see below). When you > take the transmitter off you must disable the system and re-enable it when you > put it on. VERY inconvenient. Compliance will be very poor. This is a more interesting problem. I suggest that when you take off the sensor, the act of doing so puts it in a standby mode. Half an hour later, if the sensor hasn't been donned again, it tells the base station to sound an audible alarm, reminding the user. If the user doesn't respond, the base station sends its medical alert. > 6) An AVID chip implanted in the nape of the neck or a card or necklace with a > passive transmitter could make turning the switch off and on when leaving the > home unnecessary. Excellent idea. More to the point, the chip could contain the pulse sensor. > Where ever did you get the notion that SCD victims have time to push a button? > No way. Most SCD victims just fall over dead. Here your experience is obviously greater than mine. The one time I saw someone have a heart attack, she had a lot of time to talk about it. I didn't realize this is not the norm. ------------------- I suggest I copy this discussion to CryoNet. There are people reading CryoNet who actually design hardware (well, I should say at least one person--Keith Lofstrom, an integrated circuit designer). Okay with you if I repost your msg and mine? Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=5581