Chaining Sensirion SHT7x sensors?

[Elias Aarnio]

Hello,

I am looking forward to do some humidity monitoring with Sensirion
SHT75 sensors.

Has anybody any experience on how to chain several of these to a
single loop?

Any pointers to (preferably Linux) software.

I am aware of the Windows-software and schematics at
http://peterpolm.tripod.com/sht11/id1.html

--
EliasA
Kaarina - Finland
eliaar "this is the place for the at-sign" utu.fi

 

[Charles Edmondson]

Elias Aarnio wrote:

Hello,

I am looking forward to do some humidity monitoring with Sensirion
SHT75 sensors.

Has anybody any experience on how to chain several of these to a
single loop?

Any pointers to (preferably Linux) software.

I am aware of the Windows-software and schematics at
http://peterpolm.tripod.com/sht11/id1.html

You will probably have a problem. These units are address driven, but

IIRC, the address is set at the factory, and they are all the same
address. You need to have separate clock signals to each unit (or gate
the clock to each unit) to address multiple units on the same bus.

--
Charlie
--
Edmondson Engineering
Unique Solutions to Unusual Problems

 

[Elias Aarnio]

Charlie,

Thanks for your advice

Mon, 05 Apr 2004 12:45:39 -0700, Charles Edmondson wrote:

You will probably have a problem. These units are address driven, but
IIRC, the address is set at the factory, and they are all the same
address.

And the address is not user configurable, I guess... too bad. Well -
there is always the low end solution - using same amount of buses as
sensors.

I wonder how the Sensirion people have designed their evaluation kit that
seems to be able to handle up to 20 sensors? Separate interfacing
circuitry for each sensor?
http://www.sensirion.com/en/sensors/humidity/EK-H3.htm

--
EliasA

--
Charlie

 

[Charles Edmondson]

Elias Aarnio wrote:

Charlie,

Thanks for your advice

Mon, 05 Apr 2004 12:45:39 -0700, Charles Edmondson wrote:


You will probably have a problem. These units are address driven, but
IIRC, the address is set at the factory, and they are all the same
address.


And the address is not user configurable, I guess... too bad. Well -
there is always the low end solution - using same amount of buses as
sensors.

I wonder how the Sensirion people have designed their evaluation kit that
seems to be able to handle up to 20 sensors? Separate interfacing
circuitry for each sensor?
http://www.sensirion.com/en/sensors/humidity/EK-H3.htm

They probably have a micro with separate buses to each sensor. You can

connect them all to the same data line, it is the clock that controls
the chip. Uses a little non-standard format on the interface, as well. :-('

--
Charlie
--
Edmondson Engineering
Unique Solutions to Unusual Problems