Adapting (installing) a microwave timer to set a limited time

[Russ]

Does anybody have any ideas how to adapt a microwave to make it safe
for a very forgetful elderly lady to operate. My mother has been
setting her microwave way too long lately and is in danger of having
it pulled from her assisted living apartment because she leaves food
in (to reheat) too long. She desperately needs it for heating her tea
as she has no stove (disconnected 5 years ago).
The setting would have to be no longer than 45 seconds. Any ideas?? I
believe she has a 900 watt sharp microwave and I could probably change
the timer if I knew how and where to get one. -- Thanks, Russ

 

[NSM]

| Does anybody have any ideas how to adapt a microwave to make it safe
| for a very forgetful elderly lady to operate. My mother has been
| setting her microwave way too long lately and is in danger of having
| it pulled from her assisted living apartment because she leaves food
| in (to reheat) too long. She desperately needs it for heating her tea
| as she has no stove (disconnected 5 years ago).
| The setting would have to be no longer than 45 seconds. Any ideas?? I
| believe she has a 900 watt sharp microwave and I could probably change
| the timer if I knew how and where to get one. -- Thanks, Russ

Pretty ugly. How about an el cheapo unit with the dial type timer? You could
cut a slot in the dial an add a screw to limit the top setting.

N

 

[James Sweet]

Does anybody have any ideas how to adapt a microwave to make it safe
for a very forgetful elderly lady to operate. My mother has been
setting her microwave way too long lately and is in danger of having
it pulled from her assisted living apartment because she leaves food
in (to reheat) too long. She desperately needs it for heating her tea
as she has no stove (disconnected 5 years ago).
The setting would have to be no longer than 45 seconds. Any ideas?? I
believe she has a 900 watt sharp microwave and I could probably change
the timer if I knew how and where to get one. -- Thanks, Russ

If I were working on this problem, I'd remove the original timer and design
something myself based around a cheap AVR microcontroller. Have an LED
display for the time, then simply have buttons for various presets, for
example one button for a cup of tea, another for a bag of popcorn, etc. You
can buy microwaves that already have this but what fun is that?

Also if it's one of the real cheap ovens with a mechanical timer it should
be pretty simple to install a mechanical stop of some sort so it can only be
turned to a certain point.

 

[Sam Goldwasser]

| Does anybody have any ideas how to adapt a microwave to make it safe
| for a very forgetful elderly lady to operate. My mother has been
| setting her microwave way too long lately and is in danger of having
| it pulled from her assisted living apartment because she leaves food
| in (to reheat) too long. She desperately needs it for heating her tea
| as she has no stove (disconnected 5 years ago).
| The setting would have to be no longer than 45 seconds. Any ideas?? I
| believe she has a 900 watt sharp microwave and I could probably change
| the timer if I knew how and where to get one. -- Thanks, Russ

Pretty ugly. How about an el cheapo unit with the dial type timer? You could
cut a slot in the dial an add a screw to limit the top setting.

Can you still buy ovens with mechanical timers?? I think I have a mostly
working one in the attic....

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[Gareth Magennis]

Here in the UK you can buy mechanical light switches that turn off after a
minute or so. Its a plunger you press in and it slowly moves out again to
turn off the light. They are not usually adjustable but are cheap and
simple.


Gareth.

 

[NSM]

| Can you still buy ovens with mechanical timers?? I think I have a mostly
| working one in the attic....

I think so. Perhaps a going to school special at Wal-Mart?

N

 

[James Sweet]

Can you still buy ovens with mechanical timers?? I think I have a mostly
working one in the attic....

Yep, some of the really cheap ones still use mechanical timers, stuff like
Goldstar, Funai, etc. The ones you can buy new for under $50.

 

[Richard]

Hey Russ,

How about one of these:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=29987&item=3852298955&rd=1
They're the classic darkroom timer. They are adjustable from zero to60
seconds max. When you press the start button the plug for the enlarger
is activated and the plug for the safelite is deactivated. When it
runs to the set time it resets itself and runs the same cycle when the
button is pushed again.
When I remember taking one of these apart to fix it and its a simple
clock motor driving a shaft with cams on it. The switch elements are
microswitches running on the cams. 1 NO the other NC (which would have
to be changed to NO, it might mean moving the push on connector to the
other side of the switch that's there some the tab is gone which would
require soldering ) it would be simple to disconect all the AC wire
one switch to bridge the start pad and the other in series with the
door interlock. Put the entire thing in one box with just a start
button, put a plate over the current controls with access so you can
max it out, usually 60 min. This would require you to visit your mom
every 80 cups of tea or about 26 days! You could set shorter
intervals.

Richard