Custom AC power switch

Not sure how to respond to this. It doesn't sound serious. But just to make sure, on the assumption you might be and need a technical reason, we would not be able to allow her to select the timing and power that way. The plastic card

• RFID approach, with a picture attached, allows her to select from one or two different things and to intentionally turn on the microwave. Not accidentally, when she walks by. Not always the same way, when she walks by.

Of course, it's crazy for other reasons. Just thought I'd take it seriously for a moment, though.

My preference remains an AC adaptation, though, because it has a broader application than just the microwave. But regarding the microwave, the RFID/card is probably the slickest for my needs.

Jon

Thanks. I'll do that.

Jon

OK Jon, I am seeing a bit more of your problem. You mentioned experimenting with your daughter, one appliance at a time, so lets look at the microwave oven. Where I live in Sydney, people chuck out microwave ovens and other household goods on to the footpath rather than getting them repaired for scavengers like me to pick them up. Some ovens are very easy to repair. Some of the chuck outs still work fine. I have a box load of spares from discarded ovens for my existing working unit.

I was thinking for you and your daughter. find a simple microwave oven with a mechanical timer. The "turn the knob" for so many minutes type. If you can't find one for free just buy an old one.

Now, you modify or replace the existing mechanical timing mechanism with a timer for say 2 minutes maximum. Or build- in, a 2 minute electronic timer in series with the existing mechanical timer. Terry Pinnell's site has heaps of timer circuit ideas.

Your daughter makes her pop corn in the night. Even if there was nothing in the oven, the magnetron would survive 2 minutes of abuse.

If you or your wife want more than two minutes just live with the two minute maximum time and and hit the timer again or put in your own secret over ride.

I know you were talking about cards but could your daughter learn to use a modified oven like this?

Regards, John Crighton Sydney

Yes, actually. A modified oven may be very good, in fact. We've joked that a microwave with ONLY a popcorn button and nothing more at all would probably help a fair amount. The other problem we do have is that she likes to warm up bread with cheese on it in the microwave and that should NOT have 2 minutes to it -- here, more like 30 seconds at most. This is why I'd probably use several of those convenient "cards" I mentioned -- I'd put pictures of each common thing she likes to make and work on making sure she makes the connection and uses them for the purpose. I think she would go along with this, after she got the idea okay.

There are times when she chooses to repeatedly run the microwave for a few seconds, stops it, looks, starts it again, stops, looks, etc. I think she's learned this habit the hard way -- from burning things up. I might like to experiment with some kind of accumulation counter that would allow her UP TO 2 minutes of use before it just refuses to work anymore until I "clear it" for her. This would tend to inhibit the more serious problems.

In the case of the microwave unit itself, it may actually be better for me to tinker with the front panel system either as you describe or in some fashion to allow me the flexibility for her use, with limitations as I later find I need. (Rather than using a specialized AC power outlet, for example.) That may get back to a programmable microcontroller or, at least, some manner of programmability in it so that I can discover new problems and work out new strategies to cope with them. (Hopefully, with an end in sight -- but if no exact end, then at least some very long times before I have to come up with something new.)

We are also finishing a self-contained area for her, occupying about 1400 sq ft or so of pre-existing space in our home. I've already finished up a new kitchen there and am working on a new bathroom. In total, she will have a bathroom, a large den area (family room), a toy room with her computer and stuffed animals and toys of various kinds, a bedroom, and a kitchen. Nearby, we will also have two rooms for a caregiver that can "live in" with us and her, which add another

800 sq ft, for about 2200 sq ft separate from the rest of the house we live in, with me and my wife and my youngest child (who is also autistic, but not so seriously so.) Total space is about 5000 sq ft, so we aren't cramped.

Over time, I suppose, I'd like it if the modifications we do and work through could find a broader market than just ourselves. If we can work out those things which satisfy our own needs and yet are adaptable enough to adjust to the needs of others without burdening the ideas down in the process, then that would be nice. We've already contacted one of the construction folks we know who specializes (and has long done so, some 30 years) in adapting homes. And he believes that he'd be able to make immediate use of some of what we've talked about. The state pays for some of these things, but will only pay for UL approved adaptations, if electrical, so that would be a necessary hurdle.

Oh, well.

I've enjoyed having to write about this and think more about what it is that may really be needed. It's helped me focus better, quite frankly. My thanks to you and others.

Jon

Not that serious from the expense and discomfort involved but I do believe they are using the devices in some people. The link I provided had another link to where the company implanting the chips offered a $50 discount to the first 100,000 applicants. They seem to desperately be searching for a way to avoid going under.

And, as I mentioned, it wouldn't be something for your daughter but for you and your wife so the appliances would work for you (via RFID reader) and not her. If it cost $10 and was injected into your arm with an ordinary needle perhaps you might consider it. As the technology is now, certainly not.

Robert

t.

Just thinking about the cards. Do It Yourself punched cards. with large 1/4 inch holes in them. You could make a simple card reader for cards that are post card size. Maybe with a funny face on the cards. Holes where the eyes are and holes where the teeth are sort of thing. Or just simply holes up the side of the card from a paper hole punch

So you have a funny face punched card for a cheese sandwich and a different funny face punched card for pop corn or the picture of the pop corn or sandwich.

The holes are going to determine the time that the modified simple (non fancy) microwave oven runs for.

You and your wife could use other cards for TV dinners so that your daughter sees she is not different from you two. You could have a special over ride card somewhere.

You could make the cards out of plastic sheet or plywood maybe. I am thinking 6 inches by 4 inches big enough for pictures.

OK Jon, I'll get out of your hair.

Regards, John Crighton Sydney

I read in sci.electronics.design that Jonathan Kirwan wrote (in ) about 'Custom AC power switch', on Mon, 14 Feb 2005:

Does UL already have a special policy for this situation? If not, I suggest you (and others) discuss the possibility with them.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

To avoid going to the extra trouble of RFID you could glue an iButton to each card, and fit a reader into the microwave.

I'm completely unaware of all UL policy. I've participated in products that required UL approval, but never directly in the actual approval process itself. And I imagine I'd need to talk with them, should anything get to that point.

But is there a reason to suspect that they'd set aside the necessary testing in the case of a microwave modified for "special needs?" Somehow, I think they would not do so. All I can imagine is that they'd require such microwave units to be even safer, should they know the use to which they'd be put. (I believe the entire unit would need approval as a whole, not just the control panel.)

Am I misunderstanding the question here?

Jon

I read in sci.electronics.design that Jonathan Kirwan wrote (in ) about 'Custom AC power switch', on Mon, 14 Feb 2005:

Not set aside, but carefully consider what additional testing is necessary over and above that originally carried out on the unmodified product.

Well, they would want to examine the whole product, but might well decided that testing need only be concerned with the effects of the modifications. It would be worthwhile to discuss a paper design, for example, to determine the acceptability of different power-switching techniques - relay, bought-in solid-state relay and DIY triac-based switch.

Not the question but the implication. I would hope that UL might mitigate charges for testing such products, since they are very low volume and funding is obviously limited.

The demonic reputation of UL is largely the result of people designing with their own ideas on product safety and submitting the finished product to UL. If you consult UL at an early stage you don't experience the horns and forked tail at all.

--
Regards, John Woodgate, OOO - Own Opinions Only. 
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

in

Okay, now that I think about this, it's not so interesting anymore. I don't need unique 48-bit IDs for my needs. And I'd much prefer a wireless system here. If I provide a mechanical slot with conductive fingers for a card, it will get very dirty in short order. One of the problems I have is that Athena will put her fingers into wet foods to eat (we work to clean her, but it happens all the time, just the same) and would pick up such a card and get it messy. Or else she'd finger the slot and put dirt in. The wireless arrangement where the card needs to be "near" the microwave, but where the RFID can be completely wet-sealed against environmental problems is better. If the card gets dirty, I can simply wash it. But being dirty doesn't get to be a maintenance problem of any kind and it still works fine, dirty.

An environmentally sealed RFID would be relatively maintenance-free -- lots easier to deal with than electrical contacts, etc., which definitely aren't designed with my daughter in mind!

Jon

Well, if I were to use the iButton as it is, then it would not be able to have the nice picture attached and it would be very easily lost, I suspect. If I were to make it a part of some 'card', then these problems would go away but I'd be left with a contact slot that she'd have to properly achieve in use and which would possibly gum up. And it would be more expensive on a per-card basis as well, I suspect.

But I liked thinking about it as an option and I'm going to keep it in mind.

Jon

in

It's easiest to order direct from Maxim, but you can also get them from Newark. DS1990 (ID only) is $4 in one-off, if you care to teach the reader about every individual chip. Otherwise use DS1971 (EEPROM) for $5.64 and you can store the "available functions" in the chip.

Maxim are good about samples. Get a probe socket (for example DS9092) for each device that needs a reader. You'll need a adapter for your PC to plug in to RS232, parallel port or USB, to program the buttons and test the software. The plastic fobs (DS9093A) are what I use for my sports scoring equipment - the runners wear an NVRAM button on an elastic band around the wrist, but you could tie a picture card to them.

If you get samples from Maxim, and buy an MSP430-1121STK starter kit and JTAG adapter from Olimex, you'll have a complete development environment for US$35+shipping. Check though, I think the EEPROM buttons might need 5V instead of the MSP430's 3V, which would require a level shifter.

Clifford Heath.

Fair point - but the IButton sockets are very shallow (easy to clean), have large stainless-steel contact areas, and would probably work even if filled with mashed banana. In my case the problem with grot is the additional leakage current. In street orienteering the controls are often chained around lamp-posts where dogs piss on them, which shoots the