A Humanitarian Engineering Problem 385
zrosener asks: "A have a friend who has ALS (Stephen Hawking's ailment), a particularly nasty disease in which her motor neurons deteriorate over time, slowly waylaying her. She is in pretty bad shape now, and her movement is restricted to moving her eyes, and very limited (1 inch in each direction) hand movement. She has very light bell that she uses to wake up her husband when she needs assistance, but as her strength wanes it is becoming less and less effective. She is afraid at night now that if something were to go wrong she would not be able to rouse her husband. My challenge to you is to design a noise-making-husband-alerting device cheaply and quickly assembled from strip mall parts (Radioshack, Walmart, etc.) that she could use with her extremely restricted movement. Buttons are out of the questions, as are anything that requires gripping. Analog answers are encouraged too! Please email all suggestions or post them."
Sort-of button idea (Score:5, Informative)
An idea, that is sort of like a button but not quite is to use those touch-sensetive lightswitch panels (the on/off kind, not dimmer kind) so you only need a very light touch to trigger the switch.
Breath Button (Score:5, Informative)
I know some people do morse code this way because they can't move their hands or legs.
how about a photodetector? (Score:5, Informative)
Simple. Get a small lightbulb and arrange it to shine on a photodetector. Hook it up so that a buzzer will sound if the detector output drops.
Then all she has to do is move her hand to cover the detector and the buzzer will sound.
For slightly more technical than Rat Shack, use an IR LED with corresponding detector.
Complete the circut Switch with two metal plates. (Score:5, Informative)
When she needs help she moves that tiny distance and her hand touches both plates and completes the circut which is then wired to any bell and whistle you might choose.
Simple but effective and easy.
Puto
biofeedback device? (Score:3, Informative)
Automotive micro switch (Score:2, Informative)
Hook one of these up to a relay switch and then to the power supply of a noise maker and you may have a solution
Good Luck.
Capacitive Proximity Sensors (Score:3, Informative)
We've been able to sense a finger from several inches away with one of these that has been adjusted correctly. If a person can move a finger up to an inch, even without being able to apply pressure with it, a sensor like this will have no problem detecting that.
(Yes, this is a tech report about the Mitsubishi Electric "Smart Drinking Glass" that was reported earlier [slashdot.org] on slashdot.)
Re:possible approaches (Score:1, Informative)
Re:Sort-of button idea (Score:5, Informative)
"QProx(tm) QT110/QT110H Charge-Transfer Touch Sensor"
datasheet [digikey.com]
related products [digikey.com]
Digi-Key part number 427-1006-ND. Available in single units for 2.53USD. 8-]
breath switch (Score:2, Informative)
Redundant circuit (Score:1, Informative)
Three things are needed:
1) A type of sensor (switch, photosensor, etc)
2) A noisemaker (many buzzers available)
3) A mechanism to prevent accidental firing
Radio shack has a variety of cheap switches, some using veyr little force to activate. Otherwise, the other posts will undoubtedly have recommendations for the sensor. Pick any. Cost: $2 each (need 2 or 3, see below).
Once again, Radio shack to the rescue for the buzzer. My favorite are these little 12v buzzers that sound like a fire alarm (loud as hell even at 9v). Pick any buzzer (but not a bare piezo element or speaker - they need drivers). Cost $2.
As for preventing accidental triggering when sleeping, simply wire several switches in series. All must be pressed for the alarm to sound.
Simple cicruit:
+6V ----- sw1 ---- sw2 --- sw3 --- buzz --- GND
Place it in a small metal or plastic case, attach a strechy arm/wrist band, and have her wear it. Total cost should be under $15.
Or you could take the software route and use an embedded PC104 Athlon running linux, a usb cam, and video AI to watch her eye motions. The cost would be under $2k, and software could be cobbled together in mere man months....
Re:Complete the circut Switch with two metal plate (Score:3, Informative)
Exactly. Minimal distance between the contacts for a lower amperage power supply (I don't think a standard battery will connect through 4-5 inches of human skin, but 1/2 cm obviously works). a cap in parallel with whatever you want to go off (alarm or relay) after the contacts will give you a small delay as the cap charges to keep quick brushes from setting it off.
I'd love to do an ascii circuit diagram but the lameness filter will have none of that :)
Touch activated alarm. (Score:2, Informative)
http://www.uoguelph.ca/~antoon/circ/alarm2.htm
Here's some more quick and easy circuit ideas... http://www.commlinx.com.au/schematics.htm
Clarification (Score:4, Informative)
There is alot of adaptive technology already there (Score:5, Informative)
Can she move her tounge? There are simple switching devices that can be placed in a person's mouth that can be tripped with a tounge movement.
Can she breathe (i.e. not on a ventilator). There are all kind of "sip-and-puff" devices out there that can generate several signals based on whether or not the person is sipping or blowing.
You said she can see, and has some eye movement. We have patients who are trained using eye gaze computers.
A search on google for adaptive devices, adaptive technology, a call to a local rehab hospital should all be able to provide you with information with regard to devices already available. Even if this person can't afford these things, it may give you ideas as to what you can build for her. I'm sorry I can't provide specific info, as our rehab staff/prosthetics department takes care of actual building and ordering.
When you work with people with a serious impairment, in a rehab setting, its truly remarkable what can be built/developed to take advantage of even the slightest behavior a person can elicit.
hth,
jeff
Noise Maker (Score:1, Informative)
Go find a car alarm siren (from old car or kragen, autozone, etc). They are cheap and designed for twelve volts (though you dont even need this much). I have connected one of these two a 9v bat and its VERY VERY loud. Loud enough to wake the husband and neighbors husband and wife, and their neighbors, etc. (Or somewhere close).
Re:Breath Button (Score:4, Informative)
This is probably too far down to make a difference (Score:2, Informative)
(By the way, Bernie, rest in peace. Bernie Bourdon was the man who made the place possible.)
The simplest device is a stick on a fulcrum, hung vertically. On the bottom end, tie a string, and tie that string to her bell. Her one inch of hand movement should easily be able to actuate it.
Going more high-tech, get a joystick (The old-school analog 2-button Commodore 64 kind. You can find them all over the place and Radio Shack may even still carry them) and use all direction sensors on the thing as a switch to close a circuit on a noisemaker.
Just remember to check the batteries.
Sensor ideas (Score:5, Informative)
Touch (Capactive switches)
Beam (light, ultrasound, IR triggers)
Magentic (Reed switches)
Tilt (Mercury switches)
I'll only touch on Magnetic and Tilt switches, as the others have adequately been covered by a number of people.
Magnetic switches are easily and cheaply bought anywhere you can get house alarm parts. They are very simple, last a lifetime, and work really well. Using a tiny magnet strapped to a finger allows you to use a number of reed switches so there is a choice of "what to do".
Tilt switches are easily worn on the finger, or on the head. Some care must be taken to encase the deadly mercury as the glass container may be easily broken, and mercury is poisonous. The way I would encase such switches would be by first finding a glue that is capable of sticking to GLASS and plastic, and coating the glass covered mercury switch in it. This way, if the glass cracks, the pieces will usually stay together. Let it dry, then dip it in hot plastic a number of times. You can then put it inside a piece of dense foam rubber (use a glue that sticks to rubber and plastic to keep it in place). The goal is that if you accidently stand on it, it won't break.
I've used both methods before to provide something that a disabled child can use, usually to encourage them to make some sort of movement. One Example: Mercury tilt sensor attached to a head strap with velcro (for position adjustment), to encourage the child to 'lift' their head (helps build up the neck muscles and train the brain). The mercury switch was usually wired into a radio or tape deck, switching it on or off. It also provided some real insight into what sort of music some of the kids liked, as after a little training, they would drop their head when something they didn't like would come on, and then every now and then raise their head to "check" what was playing now.
Good luck.
Re:Clarification (Score:2, Informative)