On 12/06/14 19:20, Stephen Davies wrote:
> If the PI can't to a multi hour timer then it seems to me that you
> need to front end it with a good old
>
> 7555 Timer Circuit.
>
> Remember them?
>
> Google for 755 Timer Circuits. Very easy to make. One IC, a bit of
> Veroboard and a few discrete components and a Relay, to handle the PI
> switch on/off
>
>
> Stephen D
>
>
>
> Remember them?
I remember the proper bipolar 555, not some new-fangled CMOS device!
Roger is probably going to have to deal with USB input instead of real
physical serial or parallel devices. That means there will be a few
milliseconds delay before he can read the latest status. If he's polling
once a second that should be fine, but I'd still avoid cheap clones of
Prolific devices (frequently PL2303 without serial numbers). I have
never had a problem with FTDI devices though they are a little more
expensive and they too are being cloned now.
Steve
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