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Topic: DS18B20 wrong connection (Read 1 time) previous topic - next topic

Igor1024

I've tried to connect this thermometer to Arduino Duemilanove like there http://stuff.nekhbet.ro/2009/08/23/how-to-use-the-ds18s20-and-ds18b20-temperature-sensors-with-arduino.html, and used program from there (first listing )http://tutorialpedia.org/tutorials/Working+with+Dallas+DS18S20+and+DS18B20+temperature+sensors+from+Arduino.html, but it doesn't find thermometer.
That's the way I connect it (perhaps I'am wrong in some trinket):
http://saveimg.ru/show-image.php?id=631b3bf3a2e58c887e7b43b5ea4e372e

Rusty in Texas

You have incorrectly wired your 18S20.  See figure 4 on page 6 of the manual
for the DS18S20.   The Ground and Vcc pins need to be shorted together and
connected to ground.  The Data pin goes to the digital pin on the Arduino as
well as thru a 4K7 resistor to Vcc.

The diagram on stuff.nekhbet.ro is not completely correct.

   -Rusty-

Igor1024

Sorry for stupid question, but what "Vpu" is? 

Igor1024


Rusty in Texas

Vcc is the positive supply voltage.   The 18S20 max's out at about +5.5-volts.
Glad you got it working!

Igor1024

I know about "Vcc".
What's "Vpu"? Is "Vcc" the same thing?

Rusty in Texas

I've never heard of Vpu.  Where are you seeing this??   A little
context would helpful.

Igor1024

At page 4 of DS18S20 manual (figure 4).

Rusty in Texas

Vpu is the pull up voltage supply used on the data line for "talking"
to the DS18S20.  Technically, it's not the same thing as Vcc but it
can be (well, in the spec' sheet, the supply voltage is Vdd, not Vcc).

Check out the DC Electrical Characteristics table on/about page 20.

    -Rusty-

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