[vz-dev] Volkszaehler with 1-wire counter (design remarks)

Willy Verbiest willy.verbiest at gmail.com
Tue Sep 20 09:28:45 CEST 2011

Hi Steffen,

> I'm thinking to do the following:
> Define a cron job to run a PHP script every minute
> The PHP script will read the sensor table (1-wire temperature, 1-wire
> counter).

> I would try to ommit direct access to the DB because it could create inconsistency.

I will not write directly to the tables of the Volkszaehler.
What I will do is creating a separate database with tables for the
1-wire counter and perhaps other counters.
All happens on the same computer board.

For the final design I must take some precautions as the file
operating system is on a flash disk.
The log files are already on the ram disk and are loaded at boot time
and stored on the flash disk on a regular interval.
If the database is not to big I will put the database also on the ram disk.

The values captured from the counters will be entered in the
Volkszaehler by means of the middleware like you proposed.

Is there a mechanism for compressing (reducing) older data ?
As I’m not interested in the consumption by the minuut for values that
are older then some months.

I will add all the data I have to the benchmark but at this time I’m
still in the experimenting phase.

The DS2423 counter is out of production at Maxim, I have 4 pieces so I
can use them.
My first checks shows me that I must add some kind of debouncing
between my electrical meter and the DS2423 counter.  The counts I have
are far too high comparing with my electricity consumption.

Thanks for all the hints
Willy Verbiest
Wondelgem (Gent)

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