Re: watering system, second attempt.

From: andy (news4_at_earthsong.free-online.co.uk)
Date: 08/08/04 

Date: Sun, 08 Aug 2004 05:48:18 +0100

On Sun, 08 Aug 2004 02:23:50 +0000, Rich Grise wrote:

> andy wrote:
>>
>> http://skullcap23.tripod.com/daily-water3-bw.png
>> http://skullcap23.tripod.com/daily-water3-bw.jpg
>>
>> One thing i'm not sure about is whether i need the 2N3906 on the output,
>> or whether i could drive the MOSFET directly from the 4538 monostable's
>> outputs if i used the noninverting outputs and put the diodes the other
>> way round.
>
> Keep the 2N3906. It gives a good solid pullup to drive the gate cap. This
> is what you want, isn't it?
>
> And, it looks like it waters either
> A) by timer
> B) when you push either button

It waters in the morning when one switch is set high, and in the evening
when the other one is. Moving the switches does trigger it, but that's a
side-effect.

> or is there something I'm missing?
> Is the 4538 just one-to-a-package? If so, you could lose
> one of them by just oring the switches together. :-)

There are two to a DIL package. 

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