Re: 1.5v src, LED needs 3v, now what?

Hi Chris,

Thanks for the explanation of dual supply, makes sense now.

My power source is turning out to be a troublesome factor. I like the
idea of a smaller source(lithium) but I don't know what that would do
to my cost. I have also thought of using 2 hearing aid batteries to
get 3v, but I don't know if they will have enough mAh.

I like your suggestion that I post my circuit, here it is:
http://www.pmddirect.com/temp/comparator_c.gif

(BTW: If anyone has checked out www.pmddirect.com, that is my Dad's
company, I'm not an engineer for them, thank god!) ;)

So I will explain this circuit, it's a basic sensing circuit that will
turn the LED on when the resistance at the sensor get's high enough. I
intend to have a flashing circuit that will cause the LED to flash w/
1500 ms off for each "flash" (to save power and get attention)

In no way do I think this is a correct circuit, it *works* for me, but
I'm sure it could be better/simpler and I would really value any
suggestions you may have in that regard as well.

In summary, I need a sensing circuit w/ a flashing LED(bright) in as
small a space as possible utilizing as little power as possible and I
would like it to be able to flash at the above mentioned rate for 45
days(if that is possible)

I am REALLY looking forward to any responses :)

Thanks!!
Steve

.

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