On Wed, 9 Aug 2000 21:18:26 -0500, you wrote:

>On Wed, 9 Aug 2000, John Mullan wrote:
>
>> OK, I'm beginning to see that this project may not be what I expected.
>>
>> This was supposed to be a timeout timer for use when a little 6 year =
old boy
>> needs a timeout :)
>>
>> You press a button and it starts with 5 minutes.  Each successive =
press adds
>> 5 minutes.  When time runs out it beeps (timeout over).
>>
>> Now the catch.  It goes into sleep mode when done waiting for the next=
 use.
>>
>> Obviously it won't work with the current configuration.  I really =
wanted
>> something that would be easy for the child to be able to see and watch=
 from
>> a few feet away.  An LCD wouldn't cut it.  I was hoping to stay away =
from
>> using a wall-wart but might have too.
>>
>> Anybody have other ideas???
>
>Belt? :)
>
>For my 5 yr old the threat of a timeout evokes hysteria. For the 2 yr =
old (turns
>2 on 10aug), we can tell to give herself a timeout and she'll walk to =
her room,
>wait for a while and then come out.
>
>But if you insist on a digital solution, I'd suggest having the `push =
button'
>switch turn the device on and then successive pushes will accumulate =
longer and
>longer times. The initial turn on can latch a MOSFET to provide the =
initial
>power. Then provide a means by which the PIC can switch off the MOSFET. =
The off
>resistance of the MOSFET is very high and consequently you won't have to=
 deal
>with the PIC sleep currents.
Pic sleep current is not the issue - it should be <20uA and therefore
negligible for AA batteries. There is no need to switch power to the
PIC, only the things it drives.

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