Re: [mh] 1-wire timing

[<jo...@du...>]

I can also support the use of OWFS as a layer between mH and 1-wire. For one thing it helps with debuging the whole network separatly from the 1-wire code.
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-----Original Message-----
From: Jim Duda <ji...@du...>

Date: Sat, 31 Jan 2009 20:24:25 
To: <mis...@li...>
Subject: Re: [mh] 1-wire timing


Brad Yarotsky wrote:
> I am looking at building a security system using 1-wire devices as well as
> 1-wire temperature sensing. The temperature is low priority so once a minute
> data collection would be fine, but the DS2450 I would like to read every
> couple seconds. So if a door opens and closes in a matter of seconds, it will
> be read. Can misterhouse be setup to ingore some sensors while reading others
> to speed up reading high priority devices?

I've done this using OWFS.  You can look at Owfs_Thermostat.pm. 
In this library module, I read various thermometers using a multi-second
interval.  You might find Owfs_Item.pm useful here too.

Gregg Liming wrote a Owfs xAP connector which you might find useful too.
I think it supports both temperature sensors and DS2450.  The biggest 
advantage of the xAP connector is that the OWFS and xAP processing is
outside the scope of MH and doesn't put any drain on MH itself.

> 
> The problem I am having is that Misterhouse on Windows can only pull data
> every three seconds from the 1-wire sensors. Anything more than that and
> misterhouse starts loosing time, the CPU usage stays quite high. Does eveyone
> else have this issue? Then if I try and send an email it will cause
> misterhouse to pause for a few seconds. I am afraid of missing a door openning
> when misterhouse is busy.
> 
> Would linux solve this problem? Maybe OWFS?

Yes, this is a problem with MH directly controlling one-wire.  You'll find
that OWFS is most helpful here as it does the slow back-end portion leaving
MH unharmed.  Again, check out Owfs_Item.pm.

> 
> If this is not possible then maybe the other way to deal with this is by using
> a counter (DS2423P). This would work well to tell if the door openned
> recently, but it would not tell me if the door is still open...
> 
> Any thoughts?

I've tried using the DS2450 for a doorbell sensor.  I haven't had much
success with it.  It works sometimes, but not always.

> 
> I will be monitoring 5 doors, 4 temperature (DS18S20) sensors and 2 other HVAC
> modules (DS2450)(heating system) over several hundred feet of cat5 cable.
> These will be running through a 1-wire hub. I purchased all of my items from
> http://www.hobby-boards.com.

I do this, it's quite feasible.  I have 6 temperature sensors.  I have relays
for heat and A/C using DS2450.  MH controls all my HVAC using one-wire.
I too bought all my components from hobby boards; no complaints.

Check out Owfs_Thermostat.pm and Owfs_hvac.pl.

Jim




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