That would be great.
The manufacturer claims the following bytes are being used:
Byte 0 Temperature LSB
Byte 1 Temperature MSB, t= (256*Byte1 + Byte0)/2, Range -55 - 125 °C
Byte 2 Distance [cm] unfiltered LSB
Byte 3 Distance unfiltered MSB
Byte 4 Distance [cm] filtered LSB
Byte 5 Distance filtered MSB
Byte 6 Identifier LSB= 0x02
Byte 7 Identifier MSB= 0x40, Bit 7 set after threshold is reached
Byte 8 CRC as in DS18S20 datasheet
So it should be bytes 2 and 3, and the distance would already be given
in cm.
CRC8 would be nice to have, but not really necessary.
Thanks,
Thorsten.
Am 20.11.2012 04:49, schrieb Paul Alfille:
> It's easy to add "scratchpad" back to the properties. It would be more
> elegant to add a specific "distance" value if you know how it's computed.
>
> According to he DS18S20 datasheet, only bytes 2 and 3 (temperature
> limit high and low) are writable, but Sensorbus-cm module might
> emulate and play tricks. Do you want the CRC8 byte as well?
>
> Paul Alfille
>
>
> On Mon, Nov 19, 2012 at 4:27 PM, P4trykx <[email protected]
> <mailto:[email protected]>>wrote:
>
> W dniu 19.11.2012 o 22:18 Steinar Midtskogen
> <[email protected] <mailto:[email protected]>> pisze:
>
> > [email protected] <mailto:[email protected]>writes:
> >
> >> There's a MS-Windowsprogram coming with the device which shows the
> >> distances nicely, so in principle this should work.
> >> I assume that measuring snow depth should not be much of a
> problem, but
> >> cannot verify at present time :-)
> >
> > If I had read the item description better, they claim that it can be
> > used to measure snow depth. Or rather the Sensorbus-cm-IP64 module.
> > It seems that the only difference between the Sensorbus-cm and
> > Sensorbus-cm-IP64 is the housing, but I find the price difference a
> > bit too large to jusitfy that, 79 vs 239 euro. My German isn't the
> > best, though. Do I miss something?
> >
> >> Btw, how many write cycles would the DS18S20 scratchpad withstand ?
> >
> > I think it's 100,000? But the DS18S20 is cheap and probably easy to
> > replace.
>
> So there is a microcontroller that reads data from the ultrasonic
> sensor
> and then somehow writes it DS18S20? It has to have some kind of
> switch to
> temporarily disconnect it from 1-wire bus while writing. There
> can't be
> 2 masters on one network.
>
> But I think that making an microcontroller just emulate DS18s20
> would be
> an easier(and cheaper) solution so probably there is no real DS18S20
> inside.
>
> All above are just my suspicions maybe it works some other way.
>
------------------------------------------------------------------------------
Monitor your physical, virtual and cloud infrastructure from a single
web console. Get in-depth insight into apps, servers, databases, vmware,
SAP, cloud infrastructure, etc. Download 30-day Free Trial.
Pricing starts from $795 for 25 servers or applications!
http://p.sf.net/sfu/zoho_dev2dev_nov
_______________________________________________
Owfs-developers mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/owfs-developers
